Commit f525bb2c authored by Guo Ren's avatar Guo Ren
Browse files

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: default avatarGuo Ren <guoren@linux.alibaba.com>
parent 2f78c73f

arch/csky/Kconfig

+35 −0
Original line number Diff line number Diff line
@@ -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

arch/csky/include/asm/fixmap.h

+4 −1
Original line number Diff line number Diff line
@@ -5,12 +5,16 @@ 
#define __ASM_CSKY_FIXMAP_H



#include <asm/page.h>

#include <asm/memory.h>

#ifdef CONFIG_HIGHMEM

#include <linux/threads.h>

#include <asm/kmap_types.h>

#endif



enum fixed_addresses {

#ifdef CONFIG_HAVE_TCM

	FIX_TCM = TCM_NR_PAGES,

#endif

#ifdef CONFIG_HIGHMEM

	FIX_KMAP_BEGIN,

	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
@@ -18,7 +22,6 @@ enum fixed_addresses { 
	__end_of_fixed_addresses

};



#define FIXADDR_TOP	0xffffc000

#define FIXADDR_SIZE	(__end_of_fixed_addresses << PAGE_SHIFT)

#define FIXADDR_START	(FIXADDR_TOP - FIXADDR_SIZE)

arch/csky/include/asm/memory.h

0 → 100644
+22 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



#ifndef __ASM_CSKY_MEMORY_H

#define __ASM_CSKY_MEMORY_H



#include <linux/compiler.h>

#include <linux/const.h>

#include <linux/types.h>

#include <linux/sizes.h>



#define FIXADDR_TOP	_AC(0xffffc000, UL)



#ifdef CONFIG_HAVE_TCM

#ifdef CONFIG_HAVE_DTCM

#define TCM_NR_PAGES	(CONFIG_ITCM_NR_PAGES + CONFIG_DTCM_NR_PAGES)

#else

#define TCM_NR_PAGES	(CONFIG_ITCM_NR_PAGES)

#endif

#define FIXADDR_TCM	_AC(FIXADDR_TOP - (TCM_NR_PAGES * PAGE_SIZE), UL)

#endif



#endif

arch/csky/include/asm/tcm.h

0 → 100644
+24 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



#ifndef __ASM_CSKY_TCM_H

#define __ASM_CSKY_TCM_H



#ifndef CONFIG_HAVE_TCM

#error "You should not be including tcm.h unless you have a TCM!"

#endif



#include <linux/compiler.h>



/* Tag variables with this */

#define __tcmdata __section(.tcm.data)

/* Tag constants with this */

#define __tcmconst __section(.tcm.rodata)

/* Tag functions inside TCM called from outside TCM with this */

#define __tcmfunc __section(.tcm.text) noinline

/* Tag function inside TCM called from inside TCM  with this */

#define __tcmlocalfunc __section(.tcm.text)



void *tcm_alloc(size_t len);

void tcm_free(void *addr, size_t len);



#endif

arch/csky/kernel/vmlinux.lds.S

+49 −0
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 


#include <asm/vmlinux.lds.h>

#include <asm/page.h>

#include <asm/memory.h>



OUTPUT_ARCH(csky)

ENTRY(_start)
@@ -53,6 +54,54 @@ SECTIONS 
	RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)

	_edata = .;



#ifdef CONFIG_HAVE_TCM

	.tcm_start : {

		. = ALIGN(PAGE_SIZE);

		__tcm_start = .;

	}



	.text_data_tcm FIXADDR_TCM : AT(__tcm_start)

	{

		. = ALIGN(4);

		__stcm_text_data = .;

		*(.tcm.text)

		*(.tcm.rodata)

#ifndef CONFIG_HAVE_DTCM

		*(.tcm.data)

#endif

		. = ALIGN(4);

		__etcm_text_data = .;

	}



	. = ADDR(.tcm_start) + SIZEOF(.tcm_start) + SIZEOF(.text_data_tcm);



#ifdef CONFIG_HAVE_DTCM

	#define ITCM_SIZE	CONFIG_ITCM_NR_PAGES * PAGE_SIZE



	.dtcm_start : {

		__dtcm_start = .;

	}



	.data_tcm FIXADDR_TCM + ITCM_SIZE : AT(__dtcm_start)

	{

		. = ALIGN(4);

		__stcm_data = .;

		*(.tcm.data)

		. = ALIGN(4);

		__etcm_data = .;

	}



	. = ADDR(.dtcm_start) + SIZEOF(.data_tcm);



	.tcm_end : AT(ADDR(.dtcm_start) + SIZEOF(.data_tcm)) {

#else

	.tcm_end : AT(ADDR(.tcm_start) + SIZEOF(.text_data_tcm)) {

#endif

		. = ALIGN(PAGE_SIZE);

		__tcm_end = .;

	}

#endif



	EXCEPTION_TABLE(L1_CACHE_BYTES)

	BSS_SECTION(L1_CACHE_BYTES, PAGE_SIZE, L1_CACHE_BYTES)

	VBR_BASE

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