mailbox: Add driver for Broadcom FlexRM ring manager

Some of the Broadcom iProc SoCs have FlexRM ring manager
which provides a ring-based programming interface to various
offload engines (e.g. RAID, Crypto, etc).

This patch adds a common mailbox driver for Broadcom FlexRM
ring manager which can be shared by various offload engine
drivers (implemented as mailbox clients).

Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Pramod KUMAR <pramod.kumar@broadcom.com>
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

3 files changed, 1608 insertions, 0 deletions

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 91eafb56568e..0b6f25e26c7c 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -151,4 +151,15 @@ config BCM_PDC_MBOX
 	  Mailbox implementation for the Broadcom FlexSparx DMA ring manager,
 	  which provides access to various offload engines on Broadcom
 	  SoCs, including FA2/FA+ on Northstar Plus and PDC on Northstar 2.
+
+config BCM_FLEXRM_MBOX
+	tristate "Broadcom FlexRM Mailbox"
+	depends on ARM64 || COMPILE_TEST
+	depends on HAS_DMA
+	select GENERIC_MSI_IRQ_DOMAIN
+	default ARCH_BCM_IPROC
+	help
+	  Mailbox implementation of the Broadcom FlexRM ring manager,
+	  which provides access to various offload engines on Broadcom
+	  SoCs. Say Y here if you want to use the Broadcom FlexRM.
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 7dde4f609ae8..e2bcb03cd35b 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -30,4 +30,6 @@ obj-$(CONFIG_HI6220_MBOX)	+= hi6220-mailbox.o
 
 obj-$(CONFIG_BCM_PDC_MBOX)	+= bcm-pdc-mailbox.o
 
+obj-$(CONFIG_BCM_FLEXRM_MBOX)	+= bcm-flexrm-mailbox.o
+
 obj-$(CONFIG_TEGRA_HSP_MBOX)	+= tegra-hsp.o
diff --git a/drivers/mailbox/bcm-flexrm-mailbox.c b/drivers/mailbox/bcm-flexrm-mailbox.c
new file mode 100644
index 000000000000..da67882caa7b
--- /dev/null
+++ b/drivers/mailbox/bcm-flexrm-mailbox.c
@@ -0,0 +1,1595 @@
+/* Broadcom FlexRM Mailbox Driver
+ *
+ * Copyright (C) 2017 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Each Broadcom FlexSparx4 offload engine is implemented as an
+ * extension to Broadcom FlexRM ring manager. The FlexRM ring
+ * manager provides a set of rings which can be used to submit
+ * work to a FlexSparx4 offload engine.
+ *
+ * This driver creates a mailbox controller using a set of FlexRM
+ * rings where each mailbox channel represents a separate FlexRM ring.
+ */
+
+#include <asm/barrier.h>
+#include <asm/byteorder.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/err.h>
+#include <linux/idr.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox_client.h>
+#include <linux/mailbox/brcm-message.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+/* ====== FlexRM register defines ===== */
+
+/* FlexRM configuration */
+#define RING_REGS_SIZE					0x10000
+#define RING_DESC_SIZE					8
+#define RING_DESC_INDEX(offset)				\
+			((offset) / RING_DESC_SIZE)
+#define RING_DESC_OFFSET(index)				\
+			((index) * RING_DESC_SIZE)
+#define RING_MAX_REQ_COUNT				1024
+#define RING_BD_ALIGN_ORDER				12
+#define RING_BD_ALIGN_CHECK(addr)			\
+			(!((addr) & ((0x1 << RING_BD_ALIGN_ORDER) - 1)))
+#define RING_BD_TOGGLE_INVALID(offset)			\
+			(((offset) >> RING_BD_ALIGN_ORDER) & 0x1)
+#define RING_BD_TOGGLE_VALID(offset)			\
+			(!RING_BD_TOGGLE_INVALID(offset))
+#define RING_BD_DESC_PER_REQ				32
+#define RING_BD_DESC_COUNT				\
+			(RING_MAX_REQ_COUNT * RING_BD_DESC_PER_REQ)
+#define RING_BD_SIZE					\
+			(RING_BD_DESC_COUNT * RING_DESC_SIZE)
+#define RING_CMPL_ALIGN_ORDER				13
+#define RING_CMPL_DESC_COUNT				RING_MAX_REQ_COUNT
+#define RING_CMPL_SIZE					\
+			(RING_CMPL_DESC_COUNT * RING_DESC_SIZE)
+#define RING_VER_MAGIC					0x76303031
+
+/* Per-Ring register offsets */
+#define RING_VER					0x000
+#define RING_BD_START_ADDR				0x004
+#define RING_BD_READ_PTR				0x008
+#define RING_BD_WRITE_PTR				0x00c
+#define RING_BD_READ_PTR_DDR_LS				0x010
+#define RING_BD_READ_PTR_DDR_MS				0x014
+#define RING_CMPL_START_ADDR				0x018
+#define RING_CMPL_WRITE_PTR				0x01c
+#define RING_NUM_REQ_RECV_LS				0x020
+#define RING_NUM_REQ_RECV_MS				0x024
+#define RING_NUM_REQ_TRANS_LS				0x028
+#define RING_NUM_REQ_TRANS_MS				0x02c
+#define RING_NUM_REQ_OUTSTAND				0x030
+#define RING_CONTROL					0x034
+#define RING_FLUSH_DONE					0x038
+#define RING_MSI_ADDR_LS				0x03c
+#define RING_MSI_ADDR_MS				0x040
+#define RING_MSI_CONTROL				0x048
+#define RING_BD_READ_PTR_DDR_CONTROL			0x04c
+#define RING_MSI_DATA_VALUE				0x064
+
+/* Register RING_BD_START_ADDR fields */
+#define BD_LAST_UPDATE_HW_SHIFT				28
+#define BD_LAST_UPDATE_HW_MASK				0x1
+#define BD_START_ADDR_VALUE(pa)				\
+	((u32)((((dma_addr_t)(pa)) >> RING_BD_ALIGN_ORDER) & 0x0fffffff))
+#define BD_START_ADDR_DECODE(val)			\
+	((dma_addr_t)((val) & 0x0fffffff) << RING_BD_ALIGN_ORDER)
+
+/* Register RING_CMPL_START_ADDR fields */
+#define CMPL_START_ADDR_VALUE(pa)			\
+	((u32)((((u64)(pa)) >> RING_CMPL_ALIGN_ORDER) & 0x03ffffff))
+
+/* Register RING_CONTROL fields */
+#define CONTROL_MASK_DISABLE_CONTROL			12
+#define CONTROL_FLUSH_SHIFT				5
+#define CONTROL_ACTIVE_SHIFT				4
+#define CONTROL_RATE_ADAPT_MASK				0xf
+#define CONTROL_RATE_DYNAMIC				0x0
+#define CONTROL_RATE_FAST				0x8
+#define CONTROL_RATE_MEDIUM				0x9
+#define CONTROL_RATE_SLOW				0xa
+#define CONTROL_RATE_IDLE				0xb
+
+/* Register RING_FLUSH_DONE fields */
+#define FLUSH_DONE_MASK					0x1
+
+/* Register RING_MSI_CONTROL fields */
+#define MSI_TIMER_VAL_SHIFT				16
+#define MSI_TIMER_VAL_MASK				0xffff
+#define MSI_ENABLE_SHIFT				15
+#define MSI_ENABLE_MASK					0x1
+#define MSI_COUNT_SHIFT					0
+#define MSI_COUNT_MASK					0x3ff
+
+/* Register RING_BD_READ_PTR_DDR_CONTROL fields */
+#define BD_READ_PTR_DDR_TIMER_VAL_SHIFT			16
+#define BD_READ_PTR_DDR_TIMER_VAL_MASK			0xffff
+#define BD_READ_PTR_DDR_ENABLE_SHIFT			15
+#define BD_READ_PTR_DDR_ENABLE_MASK			0x1
+
+/* ====== FlexRM ring descriptor defines ===== */
+
+/* Completion descriptor format */
+#define CMPL_OPAQUE_SHIFT			0
+#define CMPL_OPAQUE_MASK			0xffff
+#define CMPL_ENGINE_STATUS_SHIFT		16
+#define CMPL_ENGINE_STATUS_MASK			0xffff
+#define CMPL_DME_STATUS_SHIFT			32
+#define CMPL_DME_STATUS_MASK			0xffff
+#define CMPL_RM_STATUS_SHIFT			48
+#define CMPL_RM_STATUS_MASK			0xffff
+
+/* Completion DME status code */
+#define DME_STATUS_MEM_COR_ERR			BIT(0)
+#define DME_STATUS_MEM_UCOR_ERR			BIT(1)
+#define DME_STATUS_FIFO_UNDERFLOW		BIT(2)
+#define DME_STATUS_FIFO_OVERFLOW		BIT(3)
+#define DME_STATUS_RRESP_ERR			BIT(4)
+#define DME_STATUS_BRESP_ERR			BIT(5)
+#define DME_STATUS_ERROR_MASK			(DME_STATUS_MEM_COR_ERR | \
+						 DME_STATUS_MEM_UCOR_ERR | \
+						 DME_STATUS_FIFO_UNDERFLOW | \
+						 DME_STATUS_FIFO_OVERFLOW | \
+						 DME_STATUS_RRESP_ERR | \
+						 DME_STATUS_BRESP_ERR)
+
+/* Completion RM status code */
+#define RM_STATUS_CODE_SHIFT			0
+#define RM_STATUS_CODE_MASK			0x3ff
+#define RM_STATUS_CODE_GOOD			0x0
+#define RM_STATUS_CODE_AE_TIMEOUT		0x3ff
+
+/* General descriptor format */
+#define DESC_TYPE_SHIFT				60
+#define DESC_TYPE_MASK				0xf
+#define DESC_PAYLOAD_SHIFT			0
+#define DESC_PAYLOAD_MASK			0x0fffffffffffffff
+
+/* Null descriptor format  */
+#define NULL_TYPE				0
+#define NULL_TOGGLE_SHIFT			58
+#define NULL_TOGGLE_MASK			0x1
+
+/* Header descriptor format */
+#define HEADER_TYPE				1
+#define HEADER_TOGGLE_SHIFT			58
+#define HEADER_TOGGLE_MASK			0x1
+#define HEADER_ENDPKT_SHIFT			57
+#define HEADER_ENDPKT_MASK			0x1
+#define HEADER_STARTPKT_SHIFT			56
+#define HEADER_STARTPKT_MASK			0x1
+#define HEADER_BDCOUNT_SHIFT			36
+#define HEADER_BDCOUNT_MASK			0x1f
+#define HEADER_BDCOUNT_MAX			HEADER_BDCOUNT_MASK
+#define HEADER_FLAGS_SHIFT			16
+#define HEADER_FLAGS_MASK			0xffff
+#define HEADER_OPAQUE_SHIFT			0
+#define HEADER_OPAQUE_MASK			0xffff
+
+/* Source (SRC) descriptor format */
+#define SRC_TYPE				2
+#define SRC_LENGTH_SHIFT			44
+#define SRC_LENGTH_MASK				0xffff
+#define SRC_ADDR_SHIFT				0
+#define SRC_ADDR_MASK				0x00000fffffffffff
+
+/* Destination (DST) descriptor format */
+#define DST_TYPE				3
+#define DST_LENGTH_SHIFT			44
+#define DST_LENGTH_MASK				0xffff
+#define DST_ADDR_SHIFT				0
+#define DST_ADDR_MASK				0x00000fffffffffff
+
+/* Immediate (IMM) descriptor format */
+#define IMM_TYPE				4
+#define IMM_DATA_SHIFT				0
+#define IMM_DATA_MASK				0x0fffffffffffffff
+
+/* Next pointer (NPTR) descriptor format */
+#define NPTR_TYPE				5
+#define NPTR_TOGGLE_SHIFT			58
+#define NPTR_TOGGLE_MASK			0x1
+#define NPTR_ADDR_SHIFT				0
+#define NPTR_ADDR_MASK				0x00000fffffffffff
+
+/* Mega source (MSRC) descriptor format */
+#define MSRC_TYPE				6
+#define MSRC_LENGTH_SHIFT			44
+#define MSRC_LENGTH_MASK			0xffff
+#define MSRC_ADDR_SHIFT				0
+#define MSRC_ADDR_MASK				0x00000fffffffffff
+
+/* Mega destination (MDST) descriptor format */
+#define MDST_TYPE				7
+#define MDST_LENGTH_SHIFT			44
+#define MDST_LENGTH_MASK			0xffff
+#define MDST_ADDR_SHIFT				0
+#define MDST_ADDR_MASK				0x00000fffffffffff
+
+/* Source with tlast (SRCT) descriptor format */
+#define SRCT_TYPE				8
+#define SRCT_LENGTH_SHIFT			44
+#define SRCT_LENGTH_MASK			0xffff
+#define SRCT_ADDR_SHIFT				0
+#define SRCT_ADDR_MASK				0x00000fffffffffff
+
+/* Destination with tlast (DSTT) descriptor format */
+#define DSTT_TYPE				9
+#define DSTT_LENGTH_SHIFT			44
+#define DSTT_LENGTH_MASK			0xffff
+#define DSTT_ADDR_SHIFT				0
+#define DSTT_ADDR_MASK				0x00000fffffffffff
+
+/* Immediate with tlast (IMMT) descriptor format */
+#define IMMT_TYPE				10
+#define IMMT_DATA_SHIFT				0
+#define IMMT_DATA_MASK				0x0fffffffffffffff
+
+/* Descriptor helper macros */
+#define DESC_DEC(_d, _s, _m)			(((_d) >> (_s)) & (_m))
+#define DESC_ENC(_d, _v, _s, _m)		\
+			do { \
+				(_d) &= ~((u64)(_m) << (_s)); \
+				(_d) |= (((u64)(_v) & (_m)) << (_s)); \
+			} while (0)
+
+/* ====== FlexRM data structures ===== */
+
+struct flexrm_ring {
+	/* Unprotected members */
+	int num;
+	struct flexrm_mbox *mbox;
+	void __iomem *regs;
+	bool irq_requested;
+	unsigned int irq;
+	unsigned int msi_timer_val;
+	unsigned int msi_count_threshold;
+	struct ida requests_ida;
+	struct brcm_message *requests[RING_MAX_REQ_COUNT];
+	void *bd_base;
+	dma_addr_t bd_dma_base;
+	u32 bd_write_offset;
+	void *cmpl_base;
+	dma_addr_t cmpl_dma_base;
+	/* Protected members */
+	spinlock_t lock;
+	struct brcm_message *last_pending_msg;
+	u32 cmpl_read_offset;
+};
+
+struct flexrm_mbox {
+	struct device *dev;
+	void __iomem *regs;
+	u32 num_rings;
+	struct flexrm_ring *rings;
+	struct dma_pool *bd_pool;
+	struct dma_pool *cmpl_pool;
+	struct mbox_controller controller;
+};
+
+/* ====== FlexRM ring descriptor helper routines ===== */
+
+static u64 flexrm_read_desc(void *desc_ptr)
+{
+	return le64_to_cpu(*((u64 *)desc_ptr));
+}
+
+static void flexrm_write_desc(void *desc_ptr, u64 desc)
+{
+	*((u64 *)desc_ptr) = cpu_to_le64(desc);
+}
+
+static u32 flexrm_cmpl_desc_to_reqid(u64 cmpl_desc)
+{
+	return (u32)(cmpl_desc & CMPL_OPAQUE_MASK);
+}
+
+static int flexrm_cmpl_desc_to_error(u64 cmpl_desc)
+{
+	u32 status;
+
+	status = DESC_DEC(cmpl_desc, CMPL_DME_STATUS_SHIFT,
+			  CMPL_DME_STATUS_MASK);
+	if (status & DME_STATUS_ERROR_MASK)
+		return -EIO;
+
+	status = DESC_DEC(cmpl_desc, CMPL_RM_STATUS_SHIFT,
+			  CMPL_RM_STATUS_MASK);
+	status &= RM_STATUS_CODE_MASK;
+	if (status == RM_STATUS_CODE_AE_TIMEOUT)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static bool flexrm_is_next_table_desc(void *desc_ptr)
+{
+	u64 desc = flexrm_read_desc(desc_ptr);
+	u32 type = DESC_DEC(desc, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+
+	return (type == NPTR_TYPE) ? true : false;
+}
+
+static u64 flexrm_next_table_desc(u32 toggle, dma_addr_t next_addr)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, NPTR_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, toggle, NPTR_TOGGLE_SHIFT, NPTR_TOGGLE_MASK);
+	DESC_ENC(desc, next_addr, NPTR_ADDR_SHIFT, NPTR_ADDR_MASK);
+
+	return desc;
+}
+
+static u64 flexrm_null_desc(u32 toggle)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, NULL_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, toggle, NULL_TOGGLE_SHIFT, NULL_TOGGLE_MASK);
+
+	return desc;
+}
+
+static u32 flexrm_estimate_header_desc_count(u32 nhcnt)
+{
+	u32 hcnt = nhcnt / HEADER_BDCOUNT_MAX;
+
+	if (!(nhcnt % HEADER_BDCOUNT_MAX))
+		hcnt += 1;
+
+	return hcnt;
+}
+
+static void flexrm_flip_header_toogle(void *desc_ptr)
+{
+	u64 desc = flexrm_read_desc(desc_ptr);
+
+	if (desc & ((u64)0x1 << HEADER_TOGGLE_SHIFT))
+		desc &= ~((u64)0x1 << HEADER_TOGGLE_SHIFT);
+	else
+		desc |= ((u64)0x1 << HEADER_TOGGLE_SHIFT);
+
+	flexrm_write_desc(desc_ptr, desc);
+}
+
+static u64 flexrm_header_desc(u32 toggle, u32 startpkt, u32 endpkt,
+			       u32 bdcount, u32 flags, u32 opaque)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, HEADER_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, toggle, HEADER_TOGGLE_SHIFT, HEADER_TOGGLE_MASK);
+	DESC_ENC(desc, startpkt, HEADER_STARTPKT_SHIFT, HEADER_STARTPKT_MASK);
+	DESC_ENC(desc, endpkt, HEADER_ENDPKT_SHIFT, HEADER_ENDPKT_MASK);
+	DESC_ENC(desc, bdcount, HEADER_BDCOUNT_SHIFT, HEADER_BDCOUNT_MASK);
+	DESC_ENC(desc, flags, HEADER_FLAGS_SHIFT, HEADER_FLAGS_MASK);
+	DESC_ENC(desc, opaque, HEADER_OPAQUE_SHIFT, HEADER_OPAQUE_MASK);
+
+	return desc;
+}
+
+static void flexrm_enqueue_desc(u32 nhpos, u32 nhcnt, u32 reqid,
+				 u64 desc, void **desc_ptr, u32 *toggle,
+				 void *start_desc, void *end_desc)
+{
+	u64 d;
+	u32 nhavail, _toggle, _startpkt, _endpkt, _bdcount;
+
+	/* Sanity check */
+	if (nhcnt <= nhpos)
+		return;
+
+	/*
+	 * Each request or packet start with a HEADER descriptor followed
+	 * by one or more non-HEADER descriptors (SRC, SRCT, MSRC, DST,
+	 * DSTT, MDST, IMM, and IMMT). The number of non-HEADER descriptors
+	 * following a HEADER descriptor is represented by BDCOUNT field
+	 * of HEADER descriptor. The max value of BDCOUNT field is 31 which
+	 * means we can only have 31 non-HEADER descriptors following one
+	 * HEADER descriptor.
+	 *
+	 * In general use, number of non-HEADER descriptors can easily go
+	 * beyond 31. To tackle this situation, we have packet (or request)
+	 * extenstion bits (STARTPKT and ENDPKT) in the HEADER descriptor.
+	 *
+	 * To use packet extension, the first HEADER descriptor of request
+	 * (or packet) will have STARTPKT=1 and ENDPKT=0. The intermediate
+	 * HEADER descriptors will have STARTPKT=0 and ENDPKT=0. The last
+	 * HEADER descriptor will have STARTPKT=0 and ENDPKT=1. Also, the
+	 * TOGGLE bit of the first HEADER will be set to invalid state to
+	 * ensure that FlexRM does not start fetching descriptors till all
+	 * descriptors are enqueued. The user of this function will flip
+	 * the TOGGLE bit of first HEADER after all descriptors are
+	 * enqueued.
+	 */
+
+	if ((nhpos % HEADER_BDCOUNT_MAX == 0) && (nhcnt - nhpos)) {
+		/* Prepare the header descriptor */
+		nhavail = (nhcnt - nhpos);
+		_toggle = (nhpos == 0) ? !(*toggle) : (*toggle);
+		_startpkt = (nhpos == 0) ? 0x1 : 0x0;
+		_endpkt = (nhavail <= HEADER_BDCOUNT_MAX) ? 0x1 : 0x0;
+		_bdcount = (nhavail <= HEADER_BDCOUNT_MAX) ?
+				nhavail : HEADER_BDCOUNT_MAX;
+		if (nhavail <= HEADER_BDCOUNT_MAX)
+			_bdcount = nhavail;
+		else
+			_bdcount = HEADER_BDCOUNT_MAX;
+		d = flexrm_header_desc(_toggle, _startpkt, _endpkt,
+					_bdcount, 0x0, reqid);
+
+		/* Write header descriptor */
+		flexrm_write_desc(*desc_ptr, d);
+
+		/* Point to next descriptor */
+		*desc_ptr += sizeof(desc);
+		if (*desc_ptr == end_desc)
+			*desc_ptr = start_desc;
+
+		/* Skip next pointer descriptors */
+		while (flexrm_is_next_table_desc(*desc_ptr)) {
+			*toggle = (*toggle) ? 0 : 1;
+			*desc_ptr += sizeof(desc);
+			if (*desc_ptr == end_desc)
+				*desc_ptr = start_desc;
+		}
+	}
+
+	/* Write desired descriptor */
+	flexrm_write_desc(*desc_ptr, desc);
+
+	/* Point to next descriptor */
+	*desc_ptr += sizeof(desc);
+	if (*desc_ptr == end_desc)
+		*desc_ptr = start_desc;
+
+	/* Skip next pointer descriptors */
+	while (flexrm_is_next_table_desc(*desc_ptr)) {
+		*toggle = (*toggle) ? 0 : 1;
+		*desc_ptr += sizeof(desc);
+		if (*desc_ptr == end_desc)
+			*desc_ptr = start_desc;
+	}
+}
+
+static u64 flexrm_src_desc(dma_addr_t addr, unsigned int length)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, SRC_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, length, SRC_LENGTH_SHIFT, SRC_LENGTH_MASK);
+	DESC_ENC(desc, addr, SRC_ADDR_SHIFT, SRC_ADDR_MASK);
+
+	return desc;
+}
+
+static u64 flexrm_msrc_desc(dma_addr_t addr, unsigned int length_div_16)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, MSRC_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, length_div_16, MSRC_LENGTH_SHIFT, MSRC_LENGTH_MASK);
+	DESC_ENC(desc, addr, MSRC_ADDR_SHIFT, MSRC_ADDR_MASK);
+
+	return desc;
+}
+
+static u64 flexrm_dst_desc(dma_addr_t addr, unsigned int length)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, DST_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, length, DST_LENGTH_SHIFT, DST_LENGTH_MASK);
+	DESC_ENC(desc, addr, DST_ADDR_SHIFT, DST_ADDR_MASK);
+
+	return desc;
+}
+
+static u64 flexrm_mdst_desc(dma_addr_t addr, unsigned int length_div_16)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, MDST_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, length_div_16, MDST_LENGTH_SHIFT, MDST_LENGTH_MASK);
+	DESC_ENC(desc, addr, MDST_ADDR_SHIFT, MDST_ADDR_MASK);
+
+	return desc;
+}
+
+static u64 flexrm_imm_desc(u64 data)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, IMM_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, data, IMM_DATA_SHIFT, IMM_DATA_MASK);
+
+	return desc;
+}
+
+static u64 flexrm_srct_desc(dma_addr_t addr, unsigned int length)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, SRCT_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, length, SRCT_LENGTH_SHIFT, SRCT_LENGTH_MASK);
+	DESC_ENC(desc, addr, SRCT_ADDR_SHIFT, SRCT_ADDR_MASK);
+
+	return desc;
+}
+
+static u64 flexrm_dstt_desc(dma_addr_t addr, unsigned int length)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, DSTT_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, length, DSTT_LENGTH_SHIFT, DSTT_LENGTH_MASK);
+	DESC_ENC(desc, addr, DSTT_ADDR_SHIFT, DSTT_ADDR_MASK);
+
+	return desc;
+}
+
+static u64 flexrm_immt_desc(u64 data)
+{
+	u64 desc = 0;
+
+	DESC_ENC(desc, IMMT_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
+	DESC_ENC(desc, data, IMMT_DATA_SHIFT, IMMT_DATA_MASK);
+
+	return desc;
+}
+
+static bool flexrm_spu_sanity_check(struct brcm_message *msg)
+{
+	struct scatterlist *sg;
+
+	if (!msg->spu.src || !msg->spu.dst)
+		return false;
+	for (sg = msg->spu.src; sg; sg = sg_next(sg)) {
+		if (sg->length & 0xf) {
+			if (sg->length > SRC_LENGTH_MASK)
+				return false;
+		} else {
+			if (sg->length > (MSRC_LENGTH_MASK * 16))
+				return false;
+		}
+	}
+	for (sg = msg->spu.dst; sg; sg = sg_next(sg)) {
+		if (sg->length & 0xf) {
+			if (sg->length > DST_LENGTH_MASK)
+				return false;
+		} else {
+			if (sg->length > (MDST_LENGTH_MASK * 16))
+				return false;
+		}
+	}
+
+	return true;
+}
+
+static u32 flexrm_spu_estimate_nonheader_desc_count(struct brcm_message *msg)
+{
+	u32 cnt = 0;
+	unsigned int dst_target = 0;
+	struct scatterlist *src_sg = msg->spu.src, *dst_sg = msg->spu.dst;
+
+	while (src_sg || dst_sg) {
+		if (src_sg) {
+			cnt++;
+			dst_target = src_sg->length;
+			src_sg = sg_next(src_sg);
+		} else
+			dst_target = UINT_MAX;
+
+		while (dst_target && dst_sg) {
+			cnt++;
+			if (dst_sg->length < dst_target)
+				dst_target -= dst_sg->length;
+			else
+				dst_target = 0;
+			dst_sg = sg_next(dst_sg);
+		}
+	}
+
+	return cnt;
+}
+
+static int flexrm_spu_dma_map(struct device *dev, struct brcm_message *msg)
+{
+	int rc;
+
+	rc = dma_map_sg(dev, msg->spu.src, sg_nents(msg->spu.src),
+			DMA_TO_DEVICE);
+	if (rc < 0)
+		return rc;
+
+	rc = dma_map_sg(dev, msg->spu.dst, sg_nents(msg->spu.dst),
+			DMA_FROM_DEVICE);
+	if (rc < 0) {
+		dma_unmap_sg(dev, msg->spu.src, sg_nents(msg->spu.src),
+			     DMA_TO_DEVICE);
+		return rc;
+	}
+
+	return 0;
+}
+
+static void flexrm_spu_dma_unmap(struct device *dev, struct brcm_message *msg)
+{
+	dma_unmap_sg(dev, msg->spu.dst, sg_nents(msg->spu.dst),
+		     DMA_FROM_DEVICE);
+	dma_unmap_sg(dev, msg->spu.src, sg_nents(msg->spu.src),
+		     DMA_TO_DEVICE);
+}
+
+static void *flexrm_spu_write_descs(struct brcm_message *msg, u32 nhcnt,
+				     u32 reqid, void *desc_ptr, u32 toggle,
+				     void *start_desc, void *end_desc)
+{
+	u64 d;
+	u32 nhpos = 0;
+	void *orig_desc_ptr = desc_ptr;
+	unsigned int dst_target = 0;
+	struct scatterlist *src_sg = msg->spu.src, *dst_sg = msg->spu.dst;
+
+	while (src_sg || dst_sg) {
+		if (src_sg) {
+			if (sg_dma_len(src_sg) & 0xf)
+				d = flexrm_src_desc(sg_dma_address(src_sg),
+						     sg_dma_len(src_sg));
+			else
+				d = flexrm_msrc_desc(sg_dma_address(src_sg),
+						      sg_dma_len(src_sg)/16);
+			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
+					     d, &desc_ptr, &toggle,
+					     start_desc, end_desc);
+			nhpos++;
+			dst_target = sg_dma_len(src_sg);
+			src_sg = sg_next(src_sg);
+		} else
+			dst_target = UINT_MAX;
+
+		while (dst_target && dst_sg) {
+			if (sg_dma_len(dst_sg) & 0xf)
+				d = flexrm_dst_desc(sg_dma_address(dst_sg),
+						     sg_dma_len(dst_sg));
+			else
+				d = flexrm_mdst_desc(sg_dma_address(dst_sg),
+						      sg_dma_len(dst_sg)/16);
+			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
+					     d, &desc_ptr, &toggle,
+					     start_desc, end_desc);
+			nhpos++;
+			if (sg_dma_len(dst_sg) < dst_target)
+				dst_target -= sg_dma_len(dst_sg);
+			else
+				dst_target = 0;
+			dst_sg = sg_next(dst_sg);
+		}
+	}
+
+	/* Null descriptor with invalid toggle bit */
+	flexrm_write_desc(desc_ptr, flexrm_null_desc(!toggle));
+
+	/* Ensure that descriptors have been written to memory */
+	wmb();
+
+	/* Flip toggle bit in header */
+	flexrm_flip_header_toogle(orig_desc_ptr);
+
+	return desc_ptr;
+}
+
+static bool flexrm_sba_sanity_check(struct brcm_message *msg)
+{
+	u32 i;
+
+	if (!msg->sba.cmds || !msg->sba.cmds_count)
+		return false;
+
+	for (i = 0; i < msg->sba.cmds_count; i++) {
+		if (((msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_B) ||
+		     (msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_C)) &&
+		    (msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_OUTPUT))
+			return false;
+		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_B) &&
+		    (msg->sba.cmds[i].data_len > SRCT_LENGTH_MASK))
+			return false;
+		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_C) &&
+		    (msg->sba.cmds[i].data_len > SRCT_LENGTH_MASK))
+			return false;
+		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_RESP) &&
+		    (msg->sba.cmds[i].resp_len > DSTT_LENGTH_MASK))
+			return false;
+		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_OUTPUT) &&
+		    (msg->sba.cmds[i].data_len > DSTT_LENGTH_MASK))
+			return false;
+	}
+
+	return true;
+}
+
+static u32 flexrm_sba_estimate_nonheader_desc_count(struct brcm_message *msg)
+{
+	u32 i, cnt;
+
+	cnt = 0;
+	for (i = 0; i < msg->sba.cmds_count; i++) {
+		cnt++;
+
+		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_B) ||
+		    (msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_C))
+			cnt++;
+
+		if (msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_RESP)
+			cnt++;
+
+		if (msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_OUTPUT)
+			cnt++;
+	}
+
+	return cnt;
+}
+
+static void *flexrm_sba_write_descs(struct brcm_message *msg, u32 nhcnt,
+				     u32 reqid, void *desc_ptr, u32 toggle,
+				     void *start_desc, void *end_desc)
+{
+	u64 d;
+	u32 i, nhpos = 0;
+	struct brcm_sba_command *c;
+	void *orig_desc_ptr = desc_ptr;
+
+	/* Convert SBA commands into descriptors */
+	for (i = 0; i < msg->sba.cmds_count; i++) {
+		c = &msg->sba.cmds[i];
+
+		if ((c->flags & BRCM_SBA_CMD_HAS_RESP) &&
+		    (c->flags & BRCM_SBA_CMD_HAS_OUTPUT)) {
+			/* Destination response descriptor */
+			d = flexrm_dst_desc(c->resp, c->resp_len);
+			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
+					     d, &desc_ptr, &toggle,
+					     start_desc, end_desc);
+			nhpos++;
+		} else if (c->flags & BRCM_SBA_CMD_HAS_RESP) {
+			/* Destination response with tlast descriptor */
+			d = flexrm_dstt_desc(c->resp, c->resp_len);
+			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
+					     d, &desc_ptr, &toggle,
+					     start_desc, end_desc);
+			nhpos++;
+		}
+
+		if (c->flags & BRCM_SBA_CMD_HAS_OUTPUT) {
+			/* Destination with tlast descriptor */
+			d = flexrm_dstt_desc(c->data, c->data_len);
+			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
+					     d, &desc_ptr, &toggle,
+					     start_desc, end_desc);
+			nhpos++;
+		}
+
+		if (c->flags & BRCM_SBA_CMD_TYPE_B) {
+			/* Command as immediate descriptor */
+			d = flexrm_imm_desc(c->cmd);
+			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
+					     d, &desc_ptr, &toggle,
+					     start_desc, end_desc);
+			nhpos++;
+		} else {
+			/* Command as immediate descriptor with tlast */
+			d = flexrm_immt_desc(c->cmd);
+			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
+					     d, &desc_ptr, &toggle,
+					     start_desc, end_desc);
+			nhpos++;
+		}
+
+		if ((c->flags & BRCM_SBA_CMD_TYPE_B) ||
+		    (c->flags & BRCM_SBA_CMD_TYPE_C)) {
+			/* Source with tlast descriptor */
+			d = flexrm_srct_desc(c->data, c->data_len);
+			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
+					     d, &desc_ptr, &toggle,
+					     start_desc, end_desc);
+			nhpos++;
+		}
+	}
+
+	/* Null descriptor with invalid toggle bit */
+	flexrm_write_desc(desc_ptr, flexrm_null_desc(!toggle));
+
+	/* Ensure that descriptors have been written to memory */
+	wmb();
+
+	/* Flip toggle bit in header */
+	flexrm_flip_header_toogle(orig_desc_ptr);
+
+	return desc_ptr;
+}
+
+static bool flexrm_sanity_check(struct brcm_message *msg)
+{
+	if (!msg)
+		return false;
+
+	switch (msg->type) {
+	case BRCM_MESSAGE_SPU:
+		return flexrm_spu_sanity_check(msg);
+	case BRCM_MESSAGE_SBA:
+		return flexrm_sba_sanity_check(msg);
+	default:
+		return false;
+	};
+}
+
+static u32 flexrm_estimate_nonheader_desc_count(struct brcm_message *msg)
+{
+	if (!msg)
+		return 0;
+
+	switch (msg->type) {
+	case BRCM_MESSAGE_SPU:
+		return flexrm_spu_estimate_nonheader_desc_count(msg);
+	case BRCM_MESSAGE_SBA:
+		return flexrm_sba_estimate_nonheader_desc_count(msg);
+	default:
+		return 0;
+	};
+}
+
+static int flexrm_dma_map(struct device *dev, struct brcm_message *msg)
+{
+	if (!dev || !msg)
+		return -EINVAL;
+
+	switch (msg->type) {
+	case BRCM_MESSAGE_SPU:
+		return flexrm_spu_dma_map(dev, msg);
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static void flexrm_dma_unmap(struct device *dev, struct brcm_message *msg)
+{
+	if (!dev || !msg)
+		return;
+
+	switch (msg->type) {
+	case BRCM_MESSAGE_SPU:
+		flexrm_spu_dma_unmap(dev, msg);
+		break;
+	default:
+		break;
+	}
+}
+
+static void *flexrm_write_descs(struct brcm_message *msg, u32 nhcnt,
+				u32 reqid, void *desc_ptr, u32 toggle,
+				void *start_desc, void *end_desc)
+{
+	if (!msg || !desc_ptr || !start_desc || !end_desc)
+		return ERR_PTR(-ENOTSUPP);
+
+	if ((desc_ptr < start_desc) || (end_desc <= desc_ptr))
+		return ERR_PTR(-ERANGE);
+
+	switch (msg->type) {
+	case BRCM_MESSAGE_SPU:
+		return flexrm_spu_write_descs(msg, nhcnt, reqid,
+					       desc_ptr, toggle,
+					       start_desc, end_desc);
+	case BRCM_MESSAGE_SBA:
+		return flexrm_sba_write_descs(msg, nhcnt, reqid,
+					       desc_ptr, toggle,
+					       start_desc, end_desc);
+	default:
+		return ERR_PTR(-ENOTSUPP);
+	};
+}
+
+/* ====== FlexRM driver helper routines ===== */
+
+static int flexrm_new_request(struct flexrm_ring *ring,
+				struct brcm_message *batch_msg,
+				struct brcm_message *msg)
+{
+	void *next;
+	unsigned long flags;
+	u32 val, count, nhcnt;
+	u32 read_offset, write_offset;
+	bool exit_cleanup = false;
+	int ret = 0, reqid;
+
+	/* Do sanity check on message */
+	if (!flexrm_sanity_check(msg))
+		return -EIO;
+	msg->error = 0;
+
+	/* If no requests possible then save data pointer and goto done. */
+	reqid = ida_simple_get(&ring->requests_ida, 0,
+				RING_MAX_REQ_COUNT, GFP_KERNEL);
+	if (reqid < 0) {
+		spin_lock_irqsave(&ring->lock, flags);
+		if (batch_msg)
+			ring->last_pending_msg = batch_msg;
+		else
+			ring->last_pending_msg = msg;
+		spin_unlock_irqrestore(&ring->lock, flags);
+		return 0;
+	}
+	ring->requests[reqid] = msg;
+
+	/* Do DMA mappings for the message */
+	ret = flexrm_dma_map(ring->mbox->dev, msg);
+	if (ret < 0) {
+		ring->requests[reqid] = NULL;
+		ida_simple_remove(&ring->requests_ida, reqid);
+		return ret;
+	}
+
+	/* If last_pending_msg is already set then goto done with error */
+	spin_lock_irqsave(&ring->lock, flags);
+	if (ring->last_pending_msg)
+		ret = -ENOSPC;
+	spin_unlock_irqrestore(&ring->lock, flags);
+	if (ret < 0) {
+		dev_warn(ring->mbox->dev, "no space in ring %d\n", ring->num);
+		exit_cleanup = true;
+		goto exit;
+	}
+
+	/* Determine current HW BD read offset */
+	read_offset = readl_relaxed(ring->regs + RING_BD_READ_PTR);
+	val = readl_relaxed(ring->regs + RING_BD_START_ADDR);
+	read_offset *= RING_DESC_SIZE;
+	read_offset += (u32)(BD_START_ADDR_DECODE(val) - ring->bd_dma_base);
+
+	/*
+	 * Number required descriptors = number of non-header descriptors +
+	 *				 number of header descriptors +
+	 *				 1x null descriptor
+	 */
+	nhcnt = flexrm_estimate_nonheader_desc_count(msg);
+	count = flexrm_estimate_header_desc_count(nhcnt) + nhcnt + 1;
+
+	/* Check for available descriptor space. */
+	write_offset = ring->bd_write_offset;
+	while (count) {
+		if (!flexrm_is_next_table_desc(ring->bd_base + write_offset))
+			count--;
+		write_offset += RING_DESC_SIZE;
+		if (write_offset == RING_BD_SIZE)
+			write_offset = 0x0;
+		if (write_offset == read_offset)
+			break;
+	}
+	if (count) {
+		spin_lock_irqsave(&ring->lock, flags);
+		if (batch_msg)
+			ring->last_pending_msg = batch_msg;
+		else
+			ring->last_pending_msg = msg;
+		spin_unlock_irqrestore(&ring->lock, flags);
+		ret = 0;
+		exit_cleanup = true;
+		goto exit;
+	}
+
+	/* Write descriptors to ring */
+	next = flexrm_write_descs(msg, nhcnt, reqid,
+			ring->bd_base + ring->bd_write_offset,
+			RING_BD_TOGGLE_VALID(ring->bd_write_offset),
+			ring->bd_base, ring->bd_base + RING_BD_SIZE);
+	if (IS_ERR(next)) {
+		ret = PTR_ERR(next);
+		exit_cleanup = true;
+		goto exit;
+	}
+
+	/* Save ring BD write offset */
+	ring->bd_write_offset = (unsigned long)(next - ring->bd_base);
+
+exit:
+	/* Update error status in message */
+	msg->error = ret;
+
+	/* Cleanup if we failed */
+	if (exit_cleanup) {
+		flexrm_dma_unmap(ring->mbox->dev, msg);
+		ring->requests[reqid] = NULL;
+		ida_simple_remove(&ring->requests_ida, reqid);
+	}
+
+	return ret;
+}
+
+static int flexrm_process_completions(struct flexrm_ring *ring)
+{
+	u64 desc;
+	int err, count = 0;
+	unsigned long flags;
+	struct brcm_message *msg = NULL;
+	u32 reqid, cmpl_read_offset, cmpl_write_offset;
+	struct mbox_chan *chan = &ring->mbox->controller.chans[ring->num];
+
+	spin_lock_irqsave(&ring->lock, flags);
+
+	/* Check last_pending_msg */
+	if (ring->last_pending_msg) {
+		msg = ring->last_pending_msg;
+		ring->last_pending_msg = NULL;
+	}
+
+	/*
+	 * Get current completion read and write offset
+	 *
+	 * Note: We should read completion write pointer atleast once
+	 * after we get a MSI interrupt because HW maintains internal
+	 * MSI status which will allow next MSI interrupt only after
+	 * completion write pointer is read.
+	 */
+	cmpl_write_offset = readl_relaxed(ring->regs + RING_CMPL_WRITE_PTR);
+	cmpl_write_offset *= RING_DESC_SIZE;
+	cmpl_read_offset = ring->cmpl_read_offset;
+	ring->cmpl_read_offset = cmpl_write_offset;
+
+	spin_unlock_irqrestore(&ring->lock, flags);
+
+	/* If last_pending_msg was set then queue it back */
+	if (msg)
+		mbox_send_message(chan, msg);
+
+	/* For each completed request notify mailbox clients */
+	reqid = 0;
+	while (cmpl_read_offset != cmpl_write_offset) {
+		/* Dequeue next completion descriptor */
+		desc = *((u64 *)(ring->cmpl_base + cmpl_read_offset));
+
+		/* Next read offset */
+		cmpl_read_offset += RING_DESC_SIZE;
+		if (cmpl_read_offset == RING_CMPL_SIZE)
+			cmpl_read_offset = 0;
+
+		/* Decode error from completion descriptor */
+		err = flexrm_cmpl_desc_to_error(desc);
+		if (err < 0) {
+			dev_warn(ring->mbox->dev,
+				 "got completion desc=0x%lx with error %d",
+				 (unsigned long)desc, err);
+		}
+
+		/* Determine request id from completion descriptor */
+		reqid = flexrm_cmpl_desc_to_reqid(desc);
+
+		/* Determine message pointer based on reqid */
+		msg = ring->requests[reqid];
+		if (!msg) {
+			dev_warn(ring->mbox->dev,
+				 "null msg pointer for completion desc=0x%lx",
+				 (unsigned long)desc);
+			continue;
+		}
+
+		/* Release reqid for recycling */
+		ring->requests[reqid] = NULL;
+		ida_simple_remove(&ring->requests_ida, reqid);
+
+		/* Unmap DMA mappings */
+		flexrm_dma_unmap(ring->mbox->dev, msg);
+
+		/* Give-back message to mailbox client */
+		msg->error = err;
+		mbox_chan_received_data(chan, msg);
+
+		/* Increment number of completions processed */
+		count++;
+	}
+
+	return count;
+}
+
+/* ====== FlexRM interrupt handler ===== */
+
+static irqreturn_t flexrm_irq_event(int irq, void *dev_id)
+{
+	/* We only have MSI for completions so just wakeup IRQ thread */
+	/* Ring related errors will be informed via completion descriptors */
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t flexrm_irq_thread(int irq, void *dev_id)
+{
+	flexrm_process_completions(dev_id);
+
+	return IRQ_HANDLED;
+}
+
+/* ====== FlexRM mailbox callbacks ===== */
+
+static int flexrm_send_data(struct mbox_chan *chan, void *data)
+{
+	int i, rc;
+	struct flexrm_ring *ring = chan->con_priv;
+	struct brcm_message *msg = data;
+
+	if (msg->type == BRCM_MESSAGE_BATCH) {
+		for (i = msg->batch.msgs_queued;
+		     i < msg->batch.msgs_count; i++) {
+			rc = flexrm_new_request(ring, msg,
+						 &msg->batch.msgs[i]);
+			if (rc) {
+				msg->error = rc;
+				return rc;
+			}
+			msg->batch.msgs_queued++;
+		}
+		return 0;
+	}
+
+	return flexrm_new_request(ring, NULL, data);
+}
+
+static bool flexrm_peek_data(struct mbox_chan *chan)
+{
+	int cnt = flexrm_process_completions(chan->con_priv);
+
+	return (cnt > 0) ? true : false;
+}
+
+static int flexrm_startup(struct mbox_chan *chan)
+{
+	u64 d;
+	u32 val, off;
+	int ret = 0;
+	dma_addr_t next_addr;
+	struct flexrm_ring *ring = chan->con_priv;
+
+	/* Allocate BD memory */
+	ring->bd_base = dma_pool_alloc(ring->mbox->bd_pool,
+				       GFP_KERNEL, &ring->bd_dma_base);
+	if (!ring->bd_base) {
+		dev_err(ring->mbox->dev, "can't allocate BD memory\n");
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	/* Configure next table pointer entries in BD memory */
+	for (off = 0; off < RING_BD_SIZE; off += RING_DESC_SIZE) {
+		next_addr = off + RING_DESC_SIZE;
+		if (next_addr == RING_BD_SIZE)
+			next_addr = 0;
+		next_addr += ring->bd_dma_base;
+		if (RING_BD_ALIGN_CHECK(next_addr))
+			d = flexrm_next_table_desc(RING_BD_TOGGLE_VALID(off),
+						    next_addr);
+		else
+			d = flexrm_null_desc(RING_BD_TOGGLE_INVALID(off));
+		flexrm_write_desc(ring->bd_base + off, d);
+	}
+
+	/* Allocate completion memory */
+	ring->cmpl_base = dma_pool_alloc(ring->mbox->cmpl_pool,
+					 GFP_KERNEL, &ring->cmpl_dma_base);
+	if (!ring->cmpl_base) {
+		dev_err(ring->mbox->dev, "can't allocate completion memory\n");
+		ret = -ENOMEM;
+		goto fail_free_bd_memory;
+	}
+	memset(ring->cmpl_base, 0, RING_CMPL_SIZE);
+
+	/* Request IRQ */
+	if (ring->irq == UINT_MAX) {
+		dev_err(ring->mbox->dev, "ring IRQ not available\n");
+		ret = -ENODEV;
+		goto fail_free_cmpl_memory;
+	}
+	ret = request_threaded_irq(ring->irq,
+				   flexrm_irq_event,
+				   flexrm_irq_thread,
+				   0, dev_name(ring->mbox->dev), ring);
+	if (ret) {
+		dev_err(ring->mbox->dev, "failed to request ring IRQ\n");
+		goto fail_free_cmpl_memory;
+	}
+	ring->irq_requested = true;
+
+	/* Disable/inactivate ring */
+	writel_relaxed(0x0, ring->regs + RING_CONTROL);
+
+	/* Program BD start address */
+	val = BD_START_ADDR_VALUE(ring->bd_dma_base);
+	writel_relaxed(val, ring->regs + RING_BD_START_ADDR);
+
+	/* BD write pointer will be same as HW write pointer */
+	ring->bd_write_offset =
+			readl_relaxed(ring->regs + RING_BD_WRITE_PTR);
+	ring->bd_write_offset *= RING_DESC_SIZE;
+
+	/* Program completion start address */
+	val = CMPL_START_ADDR_VALUE(ring->cmpl_dma_base);
+	writel_relaxed(val, ring->regs + RING_CMPL_START_ADDR);
+
+	/* Ensure last pending message is cleared */
+	ring->last_pending_msg = NULL;
+
+	/* Completion read pointer will be same as HW write pointer */
+	ring->cmpl_read_offset =
+			readl_relaxed(ring->regs + RING_CMPL_WRITE_PTR);
+	ring->cmpl_read_offset *= RING_DESC_SIZE;
+
+	/* Read ring Tx, Rx, and Outstanding counts to clear */
+	readl_relaxed(ring->regs + RING_NUM_REQ_RECV_LS);
+	readl_relaxed(ring->regs + RING_NUM_REQ_RECV_MS);
+	readl_relaxed(ring->regs + RING_NUM_REQ_TRANS_LS);
+	readl_relaxed(ring->regs + RING_NUM_REQ_TRANS_MS);
+	readl_relaxed(ring->regs + RING_NUM_REQ_OUTSTAND);
+
+	/* Configure RING_MSI_CONTROL */
+	val = 0;
+	val |= (ring->msi_timer_val << MSI_TIMER_VAL_SHIFT);
+	val |= BIT(MSI_ENABLE_SHIFT);
+	val |= (ring->msi_count_threshold & MSI_COUNT_MASK) << MSI_COUNT_SHIFT;
+	writel_relaxed(val, ring->regs + RING_MSI_CONTROL);
+
+	/* Enable/activate ring */
+	val = BIT(CONTROL_ACTIVE_SHIFT);
+	writel_relaxed(val, ring->regs + RING_CONTROL);
+
+	return 0;
+
+fail_free_cmpl_memory:
+	dma_pool_free(ring->mbox->cmpl_pool,
+		      ring->cmpl_base, ring->cmpl_dma_base);
+	ring->cmpl_base = NULL;
+fail_free_bd_memory:
+	dma_pool_free(ring->mbox->bd_pool,
+		      ring->bd_base, ring->bd_dma_base);
+	ring->bd_base = NULL;
+fail:
+	return ret;
+}
+
+static void flexrm_shutdown(struct mbox_chan *chan)
+{
+	u32 reqid;
+	unsigned int timeout;
+	struct brcm_message *msg;
+	struct flexrm_ring *ring = chan->con_priv;
+
+	/* Disable/inactivate ring */
+	writel_relaxed(0x0, ring->regs + RING_CONTROL);
+
+	/* Flush ring with timeout of 1s */
+	timeout = 1000;
+	writel_relaxed(BIT(CONTROL_FLUSH_SHIFT),
+			ring->regs + RING_CONTROL);
+	do {
+		if (readl_relaxed(ring->regs + RING_FLUSH_DONE) &
+		    FLUSH_DONE_MASK)
+			break;
+		mdelay(1);
+	} while (timeout--);
+
+	/* Abort all in-flight requests */
+	for (reqid = 0; reqid < RING_MAX_REQ_COUNT; reqid++) {
+		msg = ring->requests[reqid];
+		if (!msg)
+			continue;
+
+		/* Release reqid for recycling */
+		ring->requests[reqid] = NULL;
+		ida_simple_remove(&ring->requests_ida, reqid);
+
+		/* Unmap DMA mappings */
+		flexrm_dma_unmap(ring->mbox->dev, msg);
+
+		/* Give-back message to mailbox client */
+		msg->error = -EIO;
+		mbox_chan_received_data(chan, msg);
+	}
+
+	/* Release IRQ */
+	if (ring->irq_requested) {
+		free_irq(ring->irq, ring);
+		ring->irq_requested = false;
+	}
+
+	/* Free-up completion descriptor ring */
+	if (ring->cmpl_base) {
+		dma_pool_free(ring->mbox->cmpl_pool,
+			      ring->cmpl_base, ring->cmpl_dma_base);
+		ring->cmpl_base = NULL;
+	}
+
+	/* Free-up BD descriptor ring */
+	if (ring->bd_base) {
+		dma_pool_free(ring->mbox->bd_pool,
+			      ring->bd_base, ring->bd_dma_base);
+		ring->bd_base = NULL;
+	}
+}
+
+static bool flexrm_last_tx_done(struct mbox_chan *chan)
+{
+	bool ret;
+	unsigned long flags;
+	struct flexrm_ring *ring = chan->con_priv;
+
+	spin_lock_irqsave(&ring->lock, flags);
+	ret = (ring->last_pending_msg) ? false : true;
+	spin_unlock_irqrestore(&ring->lock, flags);
+
+	return ret;
+}
+
+static const struct mbox_chan_ops flexrm_mbox_chan_ops = {
+	.send_data	= flexrm_send_data,
+	.startup	= flexrm_startup,
+	.shutdown	= flexrm_shutdown,
+	.last_tx_done	= flexrm_last_tx_done,
+	.peek_data	= flexrm_peek_data,
+};
+
+static struct mbox_chan *flexrm_mbox_of_xlate(struct mbox_controller *cntlr,
+					const struct of_phandle_args *pa)
+{
+	struct mbox_chan *chan;
+	struct flexrm_ring *ring;
+
+	if (pa->args_count < 3)
+		return ERR_PTR(-EINVAL);
+
+	if (pa->args[0] >= cntlr->num_chans)
+		return ERR_PTR(-ENOENT);
+
+	if (pa->args[1] > MSI_COUNT_MASK)
+		return ERR_PTR(-EINVAL);
+
+	if (pa->args[2] > MSI_TIMER_VAL_MASK)
+		return ERR_PTR(-EINVAL);
+
+	chan = &cntlr->chans[pa->args[0]];
+	ring = chan->con_priv;
+	ring->msi_count_threshold = pa->args[1];
+	ring->msi_timer_val = pa->args[2];
+
+	return chan;
+}
+
+/* ====== FlexRM platform driver ===== */
+
+static void flexrm_mbox_msi_write(struct msi_desc *desc, struct msi_msg *msg)
+{
+	struct device *dev = msi_desc_to_dev(desc);
+	struct flexrm_mbox *mbox = dev_get_drvdata(dev);
+	struct flexrm_ring *ring = &mbox->rings[desc->platform.msi_index];
+
+	/* Configure per-Ring MSI registers */
+	writel_relaxed(msg->address_lo, ring->regs + RING_MSI_ADDR_LS);
+	writel_relaxed(msg->address_hi, ring->regs + RING_MSI_ADDR_MS);
+	writel_relaxed(msg->data, ring->regs + RING_MSI_DATA_VALUE);
+}
+
+static int flexrm_mbox_probe(struct platform_device *pdev)
+{
+	int index, ret = 0;
+	void __iomem *regs;
+	void __iomem *regs_end;
+	struct msi_desc *desc;
+	struct resource *iomem;
+	struct flexrm_ring *ring;
+	struct flexrm_mbox *mbox;
+	struct device *dev = &pdev->dev;
+
+	/* Allocate driver mailbox struct */
+	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+	if (!mbox) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+	mbox->dev = dev;
+	platform_set_drvdata(pdev, mbox);
+
+	/* Get resource for registers */
+	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!iomem || (resource_size(iomem) < RING_REGS_SIZE)) {
+		ret = -ENODEV;
+		goto fail;
+	}
+
+	/* Map registers of all rings */
+	mbox->regs = devm_ioremap_resource(&pdev->dev, iomem);
+	if (IS_ERR(mbox->regs)) {
+		ret = PTR_ERR(mbox->regs);
+		dev_err(&pdev->dev, "Failed to remap mailbox regs: %d\n", ret);
+		goto fail;
+	}
+	regs_end = mbox->regs + resource_size(iomem);
+
+	/* Scan and count available rings */
+	mbox->num_rings = 0;
+	for (regs = mbox->regs; regs < regs_end; regs += RING_REGS_SIZE) {
+		if (readl_relaxed(regs + RING_VER) == RING_VER_MAGIC)
+			mbox->num_rings++;
+	}
+	if (!mbox->num_rings) {
+		ret = -ENODEV;
+		goto fail;
+	}
+
+	/* Allocate driver ring structs */
+	ring = devm_kcalloc(dev, mbox->num_rings, sizeof(*ring), GFP_KERNEL);
+	if (!ring) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+	mbox->rings = ring;
+
+	/* Initialize members of driver ring structs */
+	regs = mbox->regs;
+	for (index = 0; index < mbox->num_rings; index++) {
+		ring = &mbox->rings[index];
+		ring->num = index;
+		ring->mbox = mbox;
+		while ((regs < regs_end) &&
+		       (readl_relaxed(regs + RING_VER) != RING_VER_MAGIC))
+			regs += RING_REGS_SIZE;
+		if (regs_end <= regs) {
+			ret = -ENODEV;
+			goto fail;
+		}
+		ring->regs = regs;
+		regs += RING_REGS_SIZE;
+		ring->irq = UINT_MAX;
+		ring->irq_requested = false;
+		ring->msi_timer_val = MSI_TIMER_VAL_MASK;
+		ring->msi_count_threshold = 0x1;
+		ida_init(&ring->requests_ida);
+		memset(ring->requests, 0, sizeof(ring->requests));
+		ring->bd_base = NULL;
+		ring->bd_dma_base = 0;
+		ring->cmpl_base = NULL;
+		ring->cmpl_dma_base = 0;
+		spin_lock_init(&ring->lock);
+		ring->last_pending_msg = NULL;
+		ring->cmpl_read_offset = 0;
+	}
+
+	/* FlexRM is capable of 40-bit physical addresses only */
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(40));
+	if (ret) {
+		ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+		if (ret)
+			goto fail;
+	}
+
+	/* Create DMA pool for ring BD memory */
+	mbox->bd_pool = dma_pool_create("bd", dev, RING_BD_SIZE,
+					1 << RING_BD_ALIGN_ORDER, 0);
+	if (!mbox->bd_pool) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	/* Create DMA pool for ring completion memory */
+	mbox->cmpl_pool = dma_pool_create("cmpl", dev, RING_CMPL_SIZE,
+					  1 << RING_CMPL_ALIGN_ORDER, 0);
+	if (!mbox->cmpl_pool) {
+		ret = -ENOMEM;
+		goto fail_destroy_bd_pool;
+	}
+
+	/* Allocate platform MSIs for each ring */
+	ret = platform_msi_domain_alloc_irqs(dev, mbox->num_rings,
+						flexrm_mbox_msi_write);
+	if (ret)
+		goto fail_destroy_cmpl_pool;
+
+	/* Save alloced IRQ numbers for each ring */
+	for_each_msi_entry(desc, dev) {
+		ring = &mbox->rings[desc->platform.msi_index];
+		ring->irq = desc->irq;
+	}
+
+	/* Initialize mailbox controller */
+	mbox->controller.txdone_irq = false;
+	mbox->controller.txdone_poll = true;
+	mbox->controller.txpoll_period = 1;
+	mbox->controller.ops = &flexrm_mbox_chan_ops;
+	mbox->controller.dev = dev;
+	mbox->controller.num_chans = mbox->num_rings;
+	mbox->controller.of_xlate = flexrm_mbox_of_xlate;
+	mbox->controller.chans = devm_kcalloc(dev, mbox->num_rings,
+				sizeof(*mbox->controller.chans), GFP_KERNEL);
+	if (!mbox->controller.chans) {
+		ret = -ENOMEM;
+		goto fail_free_msis;
+	}
+	for (index = 0; index < mbox->num_rings; index++)
+		mbox->controller.chans[index].con_priv = &mbox->rings[index];
+
+	/* Register mailbox controller */
+	ret = mbox_controller_register(&mbox->controller);
+	if (ret)
+		goto fail_free_msis;
+
+	dev_info(dev, "registered flexrm mailbox with %d channels\n",
+			mbox->controller.num_chans);
+
+	return 0;
+
+fail_free_msis:
+	platform_msi_domain_free_irqs(dev);
+fail_destroy_cmpl_pool:
+	dma_pool_destroy(mbox->cmpl_pool);
+fail_destroy_bd_pool:
+	dma_pool_destroy(mbox->bd_pool);
+fail:
+	return ret;
+}
+
+static int flexrm_mbox_remove(struct platform_device *pdev)
+{
+	int index;
+	struct device *dev = &pdev->dev;
+	struct flexrm_ring *ring;
+	struct flexrm_mbox *mbox = platform_get_drvdata(pdev);
+
+	mbox_controller_unregister(&mbox->controller);
+
+	platform_msi_domain_free_irqs(dev);
+
+	dma_pool_destroy(mbox->cmpl_pool);
+	dma_pool_destroy(mbox->bd_pool);
+
+	for (index = 0; index < mbox->num_rings; index++) {
+		ring = &mbox->rings[index];
+		ida_destroy(&ring->requests_ida);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id flexrm_mbox_of_match[] = {
+	{ .compatible = "brcm,iproc-flexrm-mbox", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, flexrm_mbox_of_match);
+
+static struct platform_driver flexrm_mbox_driver = {
+	.driver = {
+		.name = "brcm-flexrm-mbox",
+		.of_match_table = flexrm_mbox_of_match,
+	},
+	.probe		= flexrm_mbox_probe,
+	.remove		= flexrm_mbox_remove,
+};
+module_platform_driver(flexrm_mbox_driver);
+
+MODULE_AUTHOR("Anup Patel <anup.patel@broadcom.com>");
+MODULE_DESCRIPTION("Broadcom FlexRM mailbox driver");
+MODULE_LICENSE("GPL v2");