armv7m: add instruction & data cache support

This patch adds armv7m instruction & data cache support.

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

2 files changed, 337 insertions, 2 deletions

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@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
+}