/* * Special handling for DW core on Intel MID platform * * Copyright (c) 2009, 2014 Intel Corporation. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. */ #include <linux/dma-mapping.h> #include <linux/dmaengine.h> #include <linux/interrupt.h> #include <linux/slab.h> #include <linux/spi/spi.h> #include <linux/types.h> #include "spi-dw.h" #ifdef CONFIG_SPI_DW_MID_DMA #include <linux/pci.h> #include <linux/platform_data/dma-dw.h> #define RX_BUSY 0 #define TX_BUSY 1 static struct dw_dma_slave mid_dma_tx = { .dst_id = 1 }; static struct dw_dma_slave mid_dma_rx = { .src_id = 0 }; static bool mid_spi_dma_chan_filter(struct dma_chan *chan, void *param) { struct dw_dma_slave *s = param; if (s->dma_dev != chan->device->dev) return false; chan->private = s; return true; } static int mid_spi_dma_init(struct dw_spi *dws) { struct pci_dev *dma_dev; struct dw_dma_slave *tx = dws->dma_tx; struct dw_dma_slave *rx = dws->dma_rx; dma_cap_mask_t mask; /* * Get pci device for DMA controller, currently it could only * be the DMA controller of Medfield */ dma_dev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0827, NULL); if (!dma_dev) return -ENODEV; dma_cap_zero(mask); dma_cap_set(DMA_SLAVE, mask); /* 1. Init rx channel */ rx->dma_dev = &dma_dev->dev; dws->rxchan = dma_request_channel(mask, mid_spi_dma_chan_filter, rx); if (!dws->rxchan) goto err_exit; dws->master->dma_rx = dws->rxchan; /* 2. Init tx channel */ tx->dma_dev = &dma_dev->dev; dws->txchan = dma_request_channel(mask, mid_spi_dma_chan_filter, tx); if (!dws->txchan) goto free_rxchan; dws->master->dma_tx = dws->txchan; dws->dma_inited = 1; return 0; free_rxchan: dma_release_channel(dws->rxchan); err_exit: return -EBUSY; } static void mid_spi_dma_exit(struct dw_spi *dws) { if (!dws->dma_inited) return; dmaengine_terminate_sync(dws->txchan); dma_release_channel(dws->txchan); dmaengine_terminate_sync(dws->rxchan); dma_release_channel(dws->rxchan); } static irqreturn_t dma_transfer(struct dw_spi *dws) { u16 irq_status = dw_readl(dws, DW_SPI_ISR); if (!irq_status) return IRQ_NONE; dw_readl(dws, DW_SPI_ICR); spi_reset_chip(dws); dev_err(&dws->master->dev, "%s: FIFO overrun/underrun\n", __func__); dws->master->cur_msg->status = -EIO; spi_finalize_current_transfer(dws->master); return IRQ_HANDLED; } static bool mid_spi_can_dma(struct spi_controller *master, struct spi_device *spi, struct spi_transfer *xfer) { struct dw_spi *dws = spi_controller_get_devdata(master); if (!dws->dma_inited) return false; return xfer->len > dws->fifo_len; } static enum dma_slave_buswidth convert_dma_width(u32 dma_width) { if (dma_width == 1) return DMA_SLAVE_BUSWIDTH_1_BYTE; else if (dma_width == 2) return DMA_SLAVE_BUSWIDTH_2_BYTES; return DMA_SLAVE_BUSWIDTH_UNDEFINED; } /* * dws->dma_chan_busy is set before the dma transfer starts, callback for tx * channel will clear a corresponding bit. */ static void dw_spi_dma_tx_done(void *arg) { struct dw_spi *dws = arg; clear_bit(TX_BUSY, &dws->dma_chan_busy); if (test_bit(RX_BUSY, &dws->dma_chan_busy)) return; spi_finalize_current_transfer(dws->master); } static struct dma_async_tx_descriptor *dw_spi_dma_prepare_tx(struct dw_spi *dws, struct spi_transfer *xfer) { struct dma_slave_config txconf; struct dma_async_tx_descriptor *txdesc; if (!xfer->tx_buf) return NULL; txconf.direction = DMA_MEM_TO_DEV; txconf.dst_addr = dws->dma_addr; txconf.dst_maxburst = 16; txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; txconf.dst_addr_width = convert_dma_width(dws->dma_width); txconf.device_fc = false; dmaengine_slave_config(dws->txchan, &txconf); txdesc = dmaengine_prep_slave_sg(dws->txchan, xfer->tx_sg.sgl, xfer->tx_sg.nents, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); if (!txdesc) return NULL; txdesc->callback = dw_spi_dma_tx_done; txdesc->callback_param = dws; return txdesc; } /* * dws->dma_chan_busy is set before the dma transfer starts, callback for rx * channel will clear a corresponding bit. */ static void dw_spi_dma_rx_done(void *arg) { struct dw_spi *dws = arg; clear_bit(RX_BUSY, &dws->dma_chan_busy); if (test_bit(TX_BUSY, &dws->dma_chan_busy)) return; spi_finalize_current_transfer(dws->master); } static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws, struct spi_transfer *xfer) { struct dma_slave_config rxconf; struct dma_async_tx_descriptor *rxdesc; if (!xfer->rx_buf) return NULL; rxconf.direction = DMA_DEV_TO_MEM; rxconf.src_addr = dws->dma_addr; rxconf.src_maxburst = 16; rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; rxconf.src_addr_width = convert_dma_width(dws->dma_width); rxconf.device_fc = false; dmaengine_slave_config(dws->rxchan, &rxconf); rxdesc = dmaengine_prep_slave_sg(dws->rxchan, xfer->rx_sg.sgl, xfer->rx_sg.nents, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); if (!rxdesc) return NULL; rxdesc->callback = dw_spi_dma_rx_done; rxdesc->callback_param = dws; return rxdesc; } static int mid_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer) { u16 dma_ctrl = 0; dw_writel(dws, DW_SPI_DMARDLR, 0xf); dw_writel(dws, DW_SPI_DMATDLR, 0x10); if (xfer->tx_buf) dma_ctrl |= SPI_DMA_TDMAE; if (xfer->rx_buf) dma_ctrl |= SPI_DMA_RDMAE; dw_writel(dws, DW_SPI_DMACR, dma_ctrl); /* Set the interrupt mask */ spi_umask_intr(dws, SPI_INT_TXOI | SPI_INT_RXUI | SPI_INT_RXOI); dws->transfer_handler = dma_transfer; return 0; } static int mid_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer) { struct dma_async_tx_descriptor *txdesc, *rxdesc; /* Prepare the TX dma transfer */ txdesc = dw_spi_dma_prepare_tx(dws, xfer); /* Prepare the RX dma transfer */ rxdesc = dw_spi_dma_prepare_rx(dws, xfer); /* rx must be started before tx due to spi instinct */ if (rxdesc) { set_bit(RX_BUSY, &dws->dma_chan_busy); dmaengine_submit(rxdesc); dma_async_issue_pending(dws->rxchan); } if (txdesc) { set_bit(TX_BUSY, &dws->dma_chan_busy); dmaengine_submit(txdesc); dma_async_issue_pending(dws->txchan); } return 0; } static void mid_spi_dma_stop(struct dw_spi *dws) { if (test_bit(TX_BUSY, &dws->dma_chan_busy)) { dmaengine_terminate_sync(dws->txchan); clear_bit(TX_BUSY, &dws->dma_chan_busy); } if (test_bit(RX_BUSY, &dws->dma_chan_busy)) { dmaengine_terminate_sync(dws->rxchan); clear_bit(RX_BUSY, &dws->dma_chan_busy); } } static const struct dw_spi_dma_ops mid_dma_ops = { .dma_init = mid_spi_dma_init, .dma_exit = mid_spi_dma_exit, .dma_setup = mid_spi_dma_setup, .can_dma = mid_spi_can_dma, .dma_transfer = mid_spi_dma_transfer, .dma_stop = mid_spi_dma_stop, }; #endif /* Some specific info for SPI0 controller on Intel MID */ /* HW info for MRST Clk Control Unit, 32b reg per controller */ #define MRST_SPI_CLK_BASE 100000000 /* 100m */ #define MRST_CLK_SPI_REG 0xff11d86c #define CLK_SPI_BDIV_OFFSET 0 #define CLK_SPI_BDIV_MASK 0x00000007 #define CLK_SPI_CDIV_OFFSET 9 #define CLK_SPI_CDIV_MASK 0x00000e00 #define CLK_SPI_DISABLE_OFFSET 8 int dw_spi_mid_init(struct dw_spi *dws) { void __iomem *clk_reg; u32 clk_cdiv; clk_reg = ioremap_nocache(MRST_CLK_SPI_REG, 16); if (!clk_reg) return -ENOMEM; /* Get SPI controller operating freq info */ clk_cdiv = readl(clk_reg + dws->bus_num * sizeof(u32)); clk_cdiv &= CLK_SPI_CDIV_MASK; clk_cdiv >>= CLK_SPI_CDIV_OFFSET; dws->max_freq = MRST_SPI_CLK_BASE / (clk_cdiv + 1); iounmap(clk_reg); #ifdef CONFIG_SPI_DW_MID_DMA dws->dma_tx = &mid_dma_tx; dws->dma_rx = &mid_dma_rx; dws->dma_ops = &mid_dma_ops; #endif return 0; }