[U-Boot] [PATCH v4 1/2] armv7m: add instruction & data cache support

[Vikas Manocha <vikas.manocha@st.com>]

This patch adds armv7m instruction & data cache support.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
cc: Christophe KERELLO <christophe.kerello@st.com>
---

Changed in v4:
- invalidate_dcache_range() & flush_dcache_range() function added.
- blank lines added.
- comments added for registers, functions & barriers.
- register names changed for better clarity.
- typecasting moved to macro definitions.

Changed in v3:
- uint32 replcaed with u32.
- multiple read of hardware register replaced with single.
- pointers replaced with macros for base address.
- register names added as comment for system control block registers.

Changed in v2:
- changed strucures for memory mapped cache registers to macros
- added lines better readability.
- replaced magic numbers with macros.

 arch/arm/cpu/armv7m/Makefile  |   3 +-
 arch/arm/cpu/armv7m/cache.c   | 336 ++++++++++++++++++++++++++++++++++++++++++
 arch/arm/include/asm/armv7m.h |  26 +++-
 arch/arm/lib/Makefile         |   2 +
 4 files changed, 363 insertions(+), 4 deletions(-)
 create mode 100644 arch/arm/cpu/armv7m/cache.c

diff --git a/arch/arm/cpu/armv7m/Makefile b/arch/arm/cpu/armv7m/Makefile
index e1a6c40..93c9085 100644
--- a/arch/arm/cpu/armv7m/Makefile
+++ b/arch/arm/cpu/armv7m/Makefile
@@ -6,6 +6,5 @@
 #
 
 extra-y := start.o
-obj-y += cpu.o
-
+obj-y += cpu.o cache.o
 obj-$(CONFIG_SYS_ARCH_TIMER) += systick-timer.o
diff --git a/arch/arm/cpu/armv7m/cache.c b/arch/arm/cpu/armv7m/cache.c
new file mode 100644
index 0000000..162cfe3
--- /dev/null
+++ b/arch/arm/cpu/armv7m/cache.c
@@ -0,0 +1,336 @@
+/*
+ * (C) Copyright 2017
+ * Vikas Manocha, ST Micoelectronics, vikas.manocha at st.com.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <asm/armv7m.h>
+#include <asm/io.h>
+
+/* Cache maintenance operation registers */
+
+#define V7M_CACHE_REG_ICIALLU		((u32 *)(V7M_CACHE_MAINT_BASE + 0x00))
+#define INVAL_ICACHE_POU		0
+#define V7M_CACHE_REG_ICIMVALU		((u32 *)(V7M_CACHE_MAINT_BASE + 0x08))
+#define V7M_CACHE_REG_DCIMVAC		((u32 *)(V7M_CACHE_MAINT_BASE + 0x0C))
+#define V7M_CACHE_REG_DCISW		((u32 *)(V7M_CACHE_MAINT_BASE + 0x10))
+#define V7M_CACHE_REG_DCCMVAU		((u32 *)(V7M_CACHE_MAINT_BASE + 0x14))
+#define V7M_CACHE_REG_DCCMVAC		((u32 *)(V7M_CACHE_MAINT_BASE + 0x18))
+#define V7M_CACHE_REG_DCCSW		((u32 *)(V7M_CACHE_MAINT_BASE + 0x1C))
+#define V7M_CACHE_REG_DCCIMVAC		((u32 *)(V7M_CACHE_MAINT_BASE + 0x20))
+#define V7M_CACHE_REG_DCCISW		((u32 *)(V7M_CACHE_MAINT_BASE + 0x24))
+#define WAYS_SHIFT			30
+#define SETS_SHIFT			5
+
+/* armv7m processor feature registers */
+
+#define V7M_PROC_REG_CLIDR		((u32 *)(V7M_PROC_FTR_BASE + 0x00))
+#define V7M_PROC_REG_CTR		((u32 *)(V7M_PROC_FTR_BASE + 0x04))
+#define V7M_PROC_REG_CCSIDR		((u32 *)(V7M_PROC_FTR_BASE + 0x08))
+#define MASK_NUM_WAYS			GENMASK(12, 3)
+#define MASK_NUM_SETS			GENMASK(27, 13)
+#define CLINE_SIZE_MASK			GENMASK(2, 0)
+#define NUM_WAYS_SHIFT			3
+#define NUM_SETS_SHIFT			13
+#define V7M_PROC_REG_CSSELR		((u32 *)(V7M_PROC_FTR_BASE + 0x0C))
+#define SEL_I_OR_D			BIT(0)
+
+enum cache_type {
+	DCACHE,
+	ICACHE,
+};
+
+/* PoU : Point of Unification, Poc: Point of Coherency */
+enum cache_action {
+	INVALIDATE_POU,		/* i-cache invalidate by address */
+	INVALIDATE_POC,		/* d-cache invalidate by address */
+	INVALIDATE_SET_WAY,	/* d-cache invalidate by sets/ways */
+	FLUSH_POU,		/* d-cache clean by address to the PoU */
+	FLUSH_POC,		/* d-cache clean by address to the PoC */
+	FLUSH_SET_WAY,		/* d-cache clean by sets/ways */
+	FLUSH_INVAL_POC,	/* d-cache clean & invalidate by addr to PoC */
+	FLUSH_INVAL_SET_WAY,	/* d-cache clean & invalidate by set/ways */
+};
+
+#ifndef CONFIG_SYS_DCACHE_OFF
+struct dcache_config {
+	u32 ways;
+	u32 sets;
+};
+
+static void get_cache_ways_sets(struct dcache_config *cache)
+{
+	u32 cache_size_id = readl(V7M_PROC_REG_CCSIDR);
+
+	cache->ways = (cache_size_id & MASK_NUM_WAYS) >> NUM_WAYS_SHIFT;
+	cache->sets = (cache_size_id & MASK_NUM_SETS) >> NUM_SETS_SHIFT;
+}
+
+/*
+ * Return the io register to perform required cache action like clean or clean
+ * & invalidate by sets/ways.
+ */
+static u32 *get_action_reg_set_ways(enum cache_action action)
+{
+	switch (action) {
+	case INVALIDATE_SET_WAY:
+		return V7M_CACHE_REG_DCISW;
+	case FLUSH_SET_WAY:
+		return V7M_CACHE_REG_DCCSW;
+	case FLUSH_INVAL_SET_WAY:
+		return V7M_CACHE_REG_DCCISW;
+	default:
+		break;
+	};
+
+	return NULL;
+}
+
+/*
+ * Return the io register to perform required cache action like clean or clean
+ * & invalidate by adddress or range.
+ */
+static u32 *get_action_reg_range(enum cache_action action)
+{
+	switch (action) {
+	case INVALIDATE_POU:
+		return V7M_CACHE_REG_ICIMVALU;
+	case INVALIDATE_POC:
+		return V7M_CACHE_REG_DCIMVAC;
+	case FLUSH_POU:
+		return V7M_CACHE_REG_DCCMVAU;
+	case FLUSH_POC:
+		return V7M_CACHE_REG_DCCMVAC;
+	case FLUSH_INVAL_POC:
+		return V7M_CACHE_REG_DCCIMVAC;
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+static u32 get_cline_size(enum cache_type type)
+{
+	u32 size;
+
+	if (type == DCACHE)
+		clrbits_le32(V7M_PROC_REG_CSSELR, BIT(SEL_I_OR_D));
+	else if (type == ICACHE)
+		setbits_le32(V7M_PROC_REG_CSSELR, BIT(SEL_I_OR_D));
+	/* Make sure cache selection is effective for next memory access */
+	dsb();
+
+	size = readl(V7M_PROC_REG_CCSIDR) & CLINE_SIZE_MASK;
+	/* Size enocoded as 2 less than log(no_of_words_in_cache_line) base 2 */
+	size = 1 << (size + 2);
+	debug("cache line size is %d\n", size);
+
+	return size;
+}
+
+/* Perform the action like invalidate/clean on a range of cache addresses */
+static int action_cache_range(enum cache_action action, u32 start_addr,
+			      int64_t size)
+{
+	u32 cline_size;
+	u32 *action_reg;
+	enum cache_type type;
+
+	action_reg = get_action_reg_range(action);
+	if (!action_reg)
+		return -EINVAL;
+	if (action == INVALIDATE_POU)
+		type = ICACHE;
+	else
+		type = DCACHE;
+
+	/* Cache line size is minium size for the cache action */
+	cline_size = get_cline_size(type);
+	/* Align start address to cache line boundary */
+	start_addr &= ~(cline_size - 1);
+	debug("total size for cache action = %llx\n", size);
+	do {
+		writel(start_addr, action_reg);
+		size -= cline_size;
+		start_addr += cline_size;
+	} while (size > cline_size);
+
+	/* Make sure cache action is effective for next memory access */
+	dsb();
+	isb();	/* Make sure instruction stream sees it */
+	debug("cache action on range done\n");
+
+	return 0;
+}
+
+/* Perform the action like invalidate/clean on all cached addresses */
+static int action_dcache_all(enum cache_action action)
+{
+	struct dcache_config cache;
+	u32 *action_reg;
+	int i, j;
+
+	action_reg = get_action_reg_set_ways(action);
+	if (!action_reg)
+		return -EINVAL;
+
+	clrbits_le32(V7M_PROC_REG_CSSELR, BIT(SEL_I_OR_D));
+	/* Make sure cache selection is effective for next memory access */
+	dsb();
+
+	get_cache_ways_sets(&cache);	/* Get number of ways & sets */
+	debug("cache: ways= %d, sets= %d\n", cache.ways + 1, cache.sets + 1);
+	for (i = cache.sets; i >= 0; i--) {
+		for (j = cache.ways; j >= 0; j--) {
+			writel((j << WAYS_SHIFT) | (i << SETS_SHIFT),
+			       action_reg);
+		}
+	}
+
+	/* Make sure cache action is effective for next memory access */
+	dsb();
+	isb();	/* Make sure instruction stream sees it */
+
+	return 0;
+}
+
+void dcache_enable(void)
+{
+	if (dcache_status())	/* return if cache already enabled */
+		return;
+
+	if (action_dcache_all(INVALIDATE_SET_WAY)) {
+		printf("ERR: D-cache not enabled\n");
+		return;
+	}
+
+	setbits_le32(&V7M_SCB->ccr, BIT(V7M_CCR_DCACHE));
+
+	/* Make sure cache action is effective for next memory access */
+	dsb();
+	isb();	/* Make sure instruction stream sees it */
+}
+
+void dcache_disable(void)
+{
+	if (!dcache_status())
+		return;
+
+	/* if dcache is enabled-> dcache disable & then flush */
+	if (action_dcache_all(FLUSH_SET_WAY)) {
+		printf("ERR: D-cache not flushed\n");
+		return;
+	}
+
+	clrbits_le32(&V7M_SCB->ccr, BIT(V7M_CCR_DCACHE));
+
+	/* Make sure cache action is effective for next memory access */
+	dsb();
+	isb();	/* Make sure instruction stream sees it */
+}
+
+int dcache_status(void)
+{
+	return (readl(&V7M_SCB->ccr) & BIT(V7M_CCR_DCACHE)) != 0;
+}
+
+void invalidate_dcache_range(unsigned long start, unsigned long stop)
+{
+	if (action_cache_range(INVALIDATE_POC, start, stop - start)) {
+		printf("ERR: D-cache not invalidated\n");
+		return;
+	}
+}
+
+void flush_dcache_range(unsigned long start, unsigned long stop)
+{
+	if (action_cache_range(FLUSH_POC, start, stop - start)) {
+		printf("ERR: D-cache not flushed\n");
+		return;
+	}
+}
+#else
+void dcache_enable(void)
+{
+	return;
+}
+
+void dcache_disable(void)
+{
+	return;
+}
+
+int dcache_status(void)
+{
+	return 0;
+}
+#endif
+
+#ifndef CONFIG_SYS_ICACHE_OFF
+
+void invalidate_icache_all(void)
+{
+	writel(INVAL_ICACHE_POU, V7M_CACHE_REG_ICIALLU);
+
+	/* Make sure cache action is effective for next memory access */
+	dsb();
+	isb();	/* Make sure instruction stream sees it */
+}
+
+void icache_enable(void)
+{
+	if (icache_status())
+		return;
+
+	invalidate_icache_all();
+	setbits_le32(&V7M_SCB->ccr, BIT(V7M_CCR_ICACHE));
+
+	/* Make sure cache action is effective for next memory access */
+	dsb();
+	isb();	/* Make sure instruction stream sees it */
+}
+
+int icache_status(void)
+{
+	return (readl(&V7M_SCB->ccr) & BIT(V7M_CCR_ICACHE)) != 0;
+}
+
+void icache_disable(void)
+{
+	if (!icache_status())
+		return;
+
+	isb();	/* flush pipeline */
+	clrbits_le32(&V7M_SCB->ccr, BIT(V7M_CCR_ICACHE));
+	isb();	/* subsequent instructions fetch see cache disable effect */
+}
+#else
+void icache_enable(void)
+{
+	return;
+}
+
+void icache_disable(void)
+{
+	return;
+}
+
+int icache_status(void)
+{
+	return 0;
+}
+#endif
+
+void enable_caches(void)
+{
+#ifndef CONFIG_SYS_ICACHE_OFF
+	icache_enable();
+#endif
+#ifndef CONFIG_SYS_DCACHE_OFF
+	dcache_enable();
+#endif
+}
diff --git a/arch/arm/include/asm/armv7m.h b/arch/arm/include/asm/armv7m.h
index 54d8a2b..ebf0f17 100644
--- a/arch/arm/include/asm/armv7m.h
+++ b/arch/arm/include/asm/armv7m.h
@@ -16,8 +16,15 @@
 .thumb
 #endif
 
-#define V7M_SCB_BASE		0xE000ED00
-#define V7M_MPU_BASE		0xE000ED90
+/* armv7m fixed base addresses */
+#define V7M_SCS_BASE		0xE000E000
+#define V7M_NVIC_BASE		(V7M_SCS_BASE + 0x0100)
+#define V7M_SCB_BASE		(V7M_SCS_BASE + 0x0D00)
+#define V7M_PROC_FTR_BASE	(V7M_SCS_BASE + 0x0D78)
+#define V7M_MPU_BASE		(V7M_SCS_BASE + 0x0D90)
+#define V7M_FPU_BASE		(V7M_SCS_BASE + 0x0F30)
+#define V7M_CACHE_MAINT_BASE	(V7M_SCS_BASE + 0x0F50)
+#define V7M_ACCESS_CNTL_BASE	(V7M_SCS_BASE + 0x0F90)
 
 #define V7M_SCB_VTOR		0x08
 
@@ -27,6 +34,18 @@ struct v7m_scb {
 	uint32_t icsr;		/* Interrupt Control and State Register */
 	uint32_t vtor;		/* Vector Table Offset Register */
 	uint32_t aircr;		/* App Interrupt and Reset Control Register */
+	uint32_t scr;		/* offset 0x10: System Control Register */
+	uint32_t ccr;		/* offset 0x14: Config and Control Register */
+	uint32_t shpr1;		/* offset 0x18: System Handler Priority Reg 1 */
+	uint32_t shpr2;		/* offset 0x1c: System Handler Priority Reg 2 */
+	uint32_t shpr3;		/* offset 0x20: System Handler Priority Reg 3 */
+	uint32_t shcrs;		/* offset 0x24: System Handler Control State */
+	uint32_t cfsr;		/* offset 0x28: Configurable Fault Status Reg */
+	uint32_t hfsr;		/* offset 0x2C: HardFault Status Register */
+	uint32_t res;		/* offset 0x30: reserved */
+	uint32_t mmar;		/* offset 0x34: MemManage Fault Address Reg */
+	uint32_t bfar;		/* offset 0x38: BusFault Address Reg */
+	uint32_t afsr;		/* offset 0x3C: Auxiliary Fault Status Reg */
 };
 #define V7M_SCB				((struct v7m_scb *)V7M_SCB_BASE)
 
@@ -39,6 +58,9 @@ struct v7m_scb {
 
 #define V7M_ICSR_VECTACT_MSK		0xFF
 
+#define V7M_CCR_DCACHE			16
+#define V7M_CCR_ICACHE			17
+
 struct v7m_mpu {
 	uint32_t type;		/* Type Register */
 	uint32_t ctrl;		/* Control Register */
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 166fa9e..52b36b3 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -55,8 +55,10 @@ endif
 
 obj-y	+= cache.o
 ifndef CONFIG_ARM64
+ifndef CONFIG_CPU_V7M
 obj-y	+= cache-cp15.o
 endif
+endif
 
 obj-y	+= psci-dt.o
 
-- 
1.9.1