ARM: 5580/2: ARM TCM (Tightly-Coupled Memory) support v3

This adds the TCM interface to Linux, when active, it will
detect and report TCM memories and sizes early in boot if
present, introduce generic TCM memory handling, provide a
generic TCM memory pool and select TCM memory for the U300
platform.

See the Documentation/arm/tcm.txt for documentation.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

10 files changed, 380 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index d778a69..1c4119c 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -46,6 +46,10 @@ config GENERIC_CLOCKEVENTS_BROADCAST
 	depends on GENERIC_CLOCKEVENTS
 	default y if SMP && !LOCAL_TIMERS
 
+config HAVE_TCM
+	bool
+	select GENERIC_ALLOCATOR
+
 config NO_IOPORT
 	bool
 
@@ -649,6 +653,7 @@ config ARCH_U300
 	bool "ST-Ericsson U300 Series"
 	depends on MMU
 	select CPU_ARM926T
+	select HAVE_TCM
 	select ARM_AMBA
 	select ARM_VIC
 	select GENERIC_TIME
diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
index b3e656c..54a1f1d 100644
--- a/arch/arm/include/asm/cputype.h
+++ b/arch/arm/include/asm/cputype.h
@@ -63,6 +63,11 @@ static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
 	return read_cpuid(CPUID_CACHETYPE);
 }
 
+static inline unsigned int __attribute_const__ read_cpuid_tcmstatus(void)
+{
+	return read_cpuid(CPUID_TCM);
+}
+
 /*
  * Intel's XScale3 core supports some v6 features (supersections, L2)
  * but advertises itself as v5 as it does not support the v6 ISA.  For
diff --git a/arch/arm/include/asm/tcm.h b/arch/arm/include/asm/tcm.h
new file mode 100644
index 0000000..5929ef5
--- /dev/null
+++ b/arch/arm/include/asm/tcm.h
@@ -0,0 +1,31 @@
+/*
+ *
+ * Copyright (C) 2008-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Author: Rickard Andersson <rickard.andersson@stericsson.com>
+ * Author: Linus Walleij <linus.walleij@stericsson.com>
+ *
+ */
+#ifndef __ASMARM_TCM_H
+#define __ASMARM_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 __attribute__((long_call)) __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
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 3213c93..6808e01 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
 obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_ARM_UNWIND)	+= unwind.o
+obj-$(CONFIG_HAVE_TCM)		+= tcm.o
 
 obj-$(CONFIG_CRUNCH)		+= crunch.o crunch-bits.o
 AFLAGS_crunch-bits.o		:= -Wa,-mcpu=ep9312
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index d4d4f77..c6c57b6 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -45,6 +45,7 @@
 
 #include "compat.h"
 #include "atags.h"
+#include "tcm.h"
 
 #ifndef MEM_SIZE
 #define MEM_SIZE	(16*1024*1024)
@@ -749,6 +750,7 @@ void __init setup_arch(char **cmdline_p)
 #endif
 
 	cpu_init();
+	tcm_init();
 
 	/*
 	 * Set up various architecture-specific pointers
diff --git a/arch/arm/kernel/tcm.c b/arch/arm/kernel/tcm.c
new file mode 100644
index 0000000..e503038
--- /dev/null
+++ b/arch/arm/kernel/tcm.c
@@ -0,0 +1,246 @@
+/*
+ * Copyright (C) 2008-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ * TCM memory handling for ARM systems
+ *
+ * Author: Linus Walleij <linus.walleij@stericsson.com>
+ * Author: Rickard Andersson <rickard.andersson@stericsson.com>
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/stddef.h>
+#include <linux/ioport.h>
+#include <linux/genalloc.h>
+#include <linux/string.h> /* memcpy */
+#include <asm/page.h> /* PAGE_SHIFT */
+#include <asm/cputype.h>
+#include <asm/mach/map.h>
+#include <mach/memory.h>
+#include "tcm.h"
+
+/* Scream and warn about misuse */
+#if !defined(ITCM_OFFSET) || !defined(ITCM_END) || \
+    !defined(DTCM_OFFSET) || !defined(DTCM_END)
+#error "TCM support selected but offsets not defined!"
+#endif
+
+static struct gen_pool *tcm_pool;
+
+/* TCM section definitions from the linker */
+extern char __itcm_start, __sitcm_text, __eitcm_text;
+extern char __dtcm_start, __sdtcm_data, __edtcm_data;
+
+/*
+ * TCM memory resources
+ */
+static struct resource dtcm_res = {
+	.name = "DTCM RAM",
+	.start = DTCM_OFFSET,
+	.end = DTCM_END,
+	.flags = IORESOURCE_MEM
+};
+
+static struct resource itcm_res = {
+	.name = "ITCM RAM",
+	.start = ITCM_OFFSET,
+	.end = ITCM_END,
+	.flags = IORESOURCE_MEM
+};
+
+static struct map_desc dtcm_iomap[] __initdata = {
+	{
+		.virtual	= DTCM_OFFSET,
+		.pfn		= __phys_to_pfn(DTCM_OFFSET),
+		.length		= (DTCM_END - DTCM_OFFSET + 1),
+		.type		= MT_UNCACHED
+	}
+};
+
+static struct map_desc itcm_iomap[] __initdata = {
+	{
+		.virtual	= ITCM_OFFSET,
+		.pfn		= __phys_to_pfn(ITCM_OFFSET),
+		.length		= (ITCM_END - ITCM_OFFSET + 1),
+		.type		= MT_UNCACHED
+	}
+};
+
+/*
+ * Allocate a chunk of TCM memory
+ */
+void *tcm_alloc(size_t len)
+{
+	unsigned long vaddr;
+
+	if (!tcm_pool)
+		return NULL;
+
+	vaddr = gen_pool_alloc(tcm_pool, len);
+	if (!vaddr)
+		return NULL;
+
+	return (void *) vaddr;
+}
+EXPORT_SYMBOL(tcm_alloc);
+
+/*
+ * Free a chunk of TCM memory
+ */
+void tcm_free(void *addr, size_t len)
+{
+	gen_pool_free(tcm_pool, (unsigned long) addr, len);
+}
+EXPORT_SYMBOL(tcm_free);
+
+
+static void __init setup_tcm_bank(u8 type, u32 offset, u32 expected_size)
+{
+	const int tcm_sizes[16] = { 0, -1, -1, 4, 8, 16, 32, 64, 128,
+				    256, 512, 1024, -1, -1, -1, -1 };
+	u32 tcm_region;
+	int tcm_size;
+
+	/* Read the special TCM region register c9, 0 */
+	if (!type)
+		asm("mrc	p15, 0, %0, c9, c1, 0"
+		    : "=r" (tcm_region));
+	else
+		asm("mrc	p15, 0, %0, c9, c1, 1"
+		    : "=r" (tcm_region));
+
+	tcm_size = tcm_sizes[(tcm_region >> 2) & 0x0f];
+	if (tcm_size < 0) {
+		pr_err("CPU: %sTCM of unknown size!\n",
+			type ? "I" : "D");
+	} else {
+		pr_info("CPU: found %sTCM %dk @ %08x, %senabled\n",
+			type ? "I" : "D",
+			tcm_size,
+			(tcm_region & 0xfffff000U),
+			(tcm_region & 1) ? "" : "not ");
+	}
+
+	if (tcm_size != expected_size) {
+		pr_crit("CPU: %sTCM was detected %dk but expected %dk!\n",
+		       type ? "I" : "D",
+		       tcm_size,
+		       expected_size);
+		/* Adjust to the expected size? what can we do... */
+	}
+
+	/* Force move the TCM bank to where we want it, enable */
+	tcm_region = offset | (tcm_region & 0x00000ffeU) | 1;
+
+	if (!type)
+		asm("mcr	p15, 0, %0, c9, c1, 0"
+		    : /* No output operands */
+		    : "r" (tcm_region));
+	else
+		asm("mcr	p15, 0, %0, c9, c1, 1"
+		    : /* No output operands */
+		    : "r" (tcm_region));
+
+	pr_debug("CPU: moved %sTCM %dk to %08x, enabled\n",
+		 type ? "I" : "D",
+		 tcm_size,
+		 (tcm_region & 0xfffff000U));
+}
+
+/*
+ * This initializes the TCM memory
+ */
+void __init tcm_init(void)
+{
+	u32 tcm_status = read_cpuid_tcmstatus();
+	char *start;
+	char *end;
+	char *ram;
+
+	/* Setup DTCM if present */
+	if (tcm_status & (1 << 16)) {
+		setup_tcm_bank(0, DTCM_OFFSET,
+			       (DTCM_END - DTCM_OFFSET + 1) >> 10);
+		request_resource(&iomem_resource, &dtcm_res);
+		iotable_init(dtcm_iomap, 1);
+		/* Copy data from RAM to DTCM */
+		start = &__sdtcm_data;
+		end   = &__edtcm_data;
+		ram   = &__dtcm_start;
+		memcpy(start, ram, (end-start));
+		pr_debug("CPU DTCM: copied data from %p - %p\n", start, end);
+	}
+
+	/* Setup ITCM if present */
+	if (tcm_status & 1) {
+		setup_tcm_bank(1, ITCM_OFFSET,
+			       (ITCM_END - ITCM_OFFSET + 1) >> 10);
+		request_resource(&iomem_resource, &itcm_res);
+		iotable_init(itcm_iomap, 1);
+		/* Copy code from RAM to ITCM */
+		start = &__sitcm_text;
+		end   = &__eitcm_text;
+		ram   = &__itcm_start;
+		memcpy(start, ram, (end-start));
+		pr_debug("CPU ITCM: copied code from %p - %p\n", start, end);
+	}
+}
+
+/*
+ * This creates the TCM memory pool and has to be done later,
+ * during the core_initicalls, since the allocator is not yet
+ * up and running when the first initialization runs.
+ */
+static int __init setup_tcm_pool(void)
+{
+	u32 tcm_status = read_cpuid_tcmstatus();
+	u32 dtcm_pool_start = (u32) &__edtcm_data;
+	u32 itcm_pool_start = (u32) &__eitcm_text;
+	int ret;
+
+	/*
+	 * Set up malloc pool, 2^2 = 4 bytes granularity since
+	 * the TCM is sometimes just 4 KiB. NB: pages and cache
+	 * line alignments does not matter in TCM!
+	 */
+	tcm_pool = gen_pool_create(2, -1);
+
+	pr_debug("Setting up TCM memory pool\n");
+
+	/* Add the rest of DTCM to the TCM pool */
+	if (tcm_status & (1 << 16)) {
+		if (dtcm_pool_start < DTCM_END) {
+			ret = gen_pool_add(tcm_pool, dtcm_pool_start,
+					   DTCM_END - dtcm_pool_start + 1, -1);
+			if (ret) {
+				pr_err("CPU DTCM: could not add DTCM " \
+				       "remainder to pool!\n");
+				return ret;
+			}
+			pr_debug("CPU DTCM: Added %08x bytes @ %08x to " \
+				 "the TCM memory pool\n",
+				 DTCM_END - dtcm_pool_start + 1,
+				 dtcm_pool_start);
+		}
+	}
+
+	/* Add the rest of ITCM to the TCM pool */
+	if (tcm_status & 1) {
+		if (itcm_pool_start < ITCM_END) {
+			ret = gen_pool_add(tcm_pool, itcm_pool_start,
+					   ITCM_END - itcm_pool_start + 1, -1);
+			if (ret) {
+				pr_err("CPU ITCM: could not add ITCM " \
+				       "remainder to pool!\n");
+				return ret;
+			}
+			pr_debug("CPU ITCM: Added %08x bytes @ %08x to " \
+				 "the TCM memory pool\n",
+				 ITCM_END - itcm_pool_start + 1,
+				 itcm_pool_start);
+		}
+	}
+	return 0;
+}
+
+core_initcall(setup_tcm_pool);
diff --git a/arch/arm/kernel/tcm.h b/arch/arm/kernel/tcm.h
new file mode 100644
index 0000000..8015ad4
--- /dev/null
+++ b/arch/arm/kernel/tcm.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2008-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ * TCM memory handling for ARM systems
+ *
+ * Author: Linus Walleij <linus.walleij@stericsson.com>
+ * Author: Rickard Andersson <rickard.andersson@stericsson.com>
+ */
+
+#ifdef CONFIG_HAVE_TCM
+void __init tcm_init(void);
+#else
+/* No TCM support, just blank inlines to be optimized out */
+inline void tcm_init(void)
+{
+}
+#endif
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 6937102..39d3ffb 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -198,6 +198,63 @@ SECTIONS
 	}
 	_edata_loc = __data_loc + SIZEOF(.data);
 
+#ifdef CONFIG_HAVE_TCM
+        /*
+	 * We align everything to a page boundary so we can
+	 * free it after init has commenced and TCM contents have
+	 * been copied to its destination.
+	 */
+	.tcm_start : {
+		. = ALIGN(PAGE_SIZE);
+		__tcm_start = .;
+		__itcm_start = .;
+	}
+
+	/*
+	 * Link these to the ITCM RAM
+	 * Put VMA to the TCM address and LMA to the common RAM
+	 * and we'll upload the contents from RAM to TCM and free
+	 * the used RAM after that.
+	 */
+	.text_itcm ITCM_OFFSET : AT(__itcm_start)
+	{
+		__sitcm_text = .;
+		*(.tcm.text)
+		*(.tcm.rodata)
+		. = ALIGN(4);
+		__eitcm_text = .;
+	}
+
+	/*
+	 * Reset the dot pointer, this is needed to create the
+	 * relative __dtcm_start below (to be used as extern in code).
+	 */
+	. = ADDR(.tcm_start) + SIZEOF(.tcm_start) + SIZEOF(.text_itcm);
+
+	.dtcm_start : {
+		__dtcm_start = .;
+	}
+
+	/* TODO: add remainder of ITCM as well, that can be used for data! */
+	.data_dtcm DTCM_OFFSET : AT(__dtcm_start)
+	{
+		. = ALIGN(4);
+		__sdtcm_data = .;
+		*(.tcm.data)
+		. = ALIGN(4);
+		__edtcm_data = .;
+	}
+
+	/* Reset the dot pointer or the linker gets confused */
+	. = ADDR(.dtcm_start) + SIZEOF(.data_dtcm);
+
+	/* End marker for freeing TCM copy in linked object */
+	.tcm_end : AT(ADDR(.dtcm_start) + SIZEOF(.data_dtcm)){
+		. = ALIGN(PAGE_SIZE);
+		__tcm_end = .;
+	}
+#endif
+
 	.bss : {
 		__bss_start = .;	/* BSS				*/
 		*(.bss)
diff --git a/arch/arm/mach-u300/include/mach/memory.h b/arch/arm/mach-u300/include/mach/memory.h
index bf134bc..ab000df 100644
--- a/arch/arm/mach-u300/include/mach/memory.h
+++ b/arch/arm/mach-u300/include/mach/memory.h
@@ -35,6 +35,14 @@
 #endif
 
 /*
+ * TCM memory whereabouts
+ */
+#define ITCM_OFFSET	0xffff2000
+#define ITCM_END	0xffff3fff
+#define DTCM_OFFSET	0xffff4000
+#define DTCM_END	0xffff5fff
+
+/*
  * We enable a real big DMA buffer if need be.
  */
 #define CONSISTENT_DMA_SIZE SZ_4M
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index ea36186..764d5dc 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -613,6 +613,14 @@ void __init mem_init(void)
 
 void free_initmem(void)
 {
+#ifdef CONFIG_HAVE_TCM
+	extern char *__tcm_start, *__tcm_end;
+
+	totalram_pages += free_area(__phys_to_pfn(__pa(__tcm_start)),
+				    __phys_to_pfn(__pa(__tcm_end)),
+				    "TCM link");
+#endif
+
 	if (!machine_is_integrator() && !machine_is_cintegrator())
 		totalram_pages += free_area(__phys_to_pfn(__pa(__init_begin)),
 					    __phys_to_pfn(__pa(__init_end)),