csky: Tightly-Coupled Memory or Sram support

The implementation are not only used by TCM but also used by sram on
SOC bus. It follow existed linux tcm software interface, so that old
tcm application codes could be re-used directly.

Software interface list in asm/tcm.h:
 - Variables/Const: 	__tcmdata, __tcmconst
 - Functions:		__tcmfunc, __tcmlocalfunc
 - Malloc/Free:		tcm_alloc, tcm_free

In linux menuconfig:
 - Choose a TCM contain instrctions + data or separated in ITCM/DTCM.
 - Determine TCM_BASE (DTCM_BASE) in phyiscal address.
 - Determine size of TCM or ITCM(DTCM) in page counts.

Here is hello tcm example from Documentation/arm/tcm.rst which could
be directly used:

/* Uninitialized data */
static u32 __tcmdata tcmvar;
/* Initialized data */
static u32 __tcmdata tcmassigned = 0x2BADBABEU;
/* Constant */
static const u32 __tcmconst tcmconst = 0xCAFEBABEU;

static void __tcmlocalfunc tcm_to_tcm(void)
{
	int i;
	for (i = 0; i < 100; i++)
		tcmvar ++;
}

static void __tcmfunc hello_tcm(void)
{
	/* Some abstract code that runs in ITCM */
	int i;
	for (i = 0; i < 100; i++) {
		tcmvar ++;
	}
	tcm_to_tcm();
}

static void __init test_tcm(void)
{
	u32 *tcmem;
	int i;

	hello_tcm();
	printk("Hello TCM executed from ITCM RAM\n");

	printk("TCM variable from testrun: %u @ %p\n", tcmvar, &tcmvar);
	tcmvar = 0xDEADBEEFU;
	printk("TCM variable: 0x%x @ %p\n", tcmvar, &tcmvar);

	printk("TCM assigned variable: 0x%x @ %p\n", tcmassigned, &tcmassigned);

	printk("TCM constant: 0x%x @ %p\n", tcmconst, &tcmconst);

	/* Allocate some TCM memory from the pool */
	tcmem = tcm_alloc(20);
	if (tcmem) {
		printk("TCM Allocated 20 bytes of TCM @ %p\n", tcmem);
		tcmem[0] = 0xDEADBEEFU;
		tcmem[1] = 0x2BADBABEU;
		tcmem[2] = 0xCAFEBABEU;
		tcmem[3] = 0xDEADBEEFU;
		tcmem[4] = 0x2BADBABEU;
		for (i = 0; i < 5; i++)
			printk("TCM tcmem[%d] = %08x\n", i, tcmem[i]);
		tcm_free(tcmem, 20);
	}
}

TODO:
 - Separate fixup mapping from highmem
 - Support abiv1

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index ea7f3b890d03..fc92f08f0017 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -189,6 +189,41 @@ config CPU_PM_STOP
 	bool "stop"
 endchoice
 
+menuconfig HAVE_TCM
+	bool "Tightly-Coupled/Sram Memory"
+	depends on HIGHMEM
+	select GENERIC_ALLOCATOR
+	help
+	  The implementation are not only used by TCM (Tightly-Coupled Meory)
+	  but also used by sram on SOC bus. It follow existed linux tcm
+	  software interface, so that old tcm application codes could be
+	  re-used directly.
+
+if HAVE_TCM
+config ITCM_RAM_BASE
+	hex "ITCM ram base"
+	default 0xffffffff
+
+config ITCM_NR_PAGES
+	int "Page count of ITCM size: NR*4KB"
+	range 1 256
+	default 32
+
+config HAVE_DTCM
+	bool "DTCM Support"
+
+config DTCM_RAM_BASE
+	hex "DTCM ram base"
+	depends on HAVE_DTCM
+	default 0xffffffff
+
+config DTCM_NR_PAGES
+	int "Page count of DTCM size: NR*4KB"
+	depends on HAVE_DTCM
+	range 1 256
+	default 32
+endif
+
 config CPU_HAS_VDSP
 	bool "CPU has VDSP coprocessor"
 	depends on CPU_HAS_FPU && CPU_HAS_FPUV2