[PATCH] RFC: ARM: cache-l2x0: update workaround for PL310 errata 727915

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From: Colin Cross <ccross@xxxxxxxxxxx>

ARM errata 727915 for PL310 has been updated to include a new
workaround required for PL310 r2p0 for l2x0_flush_all, which also
affects l2x0_clean_all in my testing. For r2p0, clean or flush
each set/way individually. For r3p0 or greater, use the debug
register for cleaning and flushing.

Requires exporting the cache_id, sets and ways detected in the
init function for later use.

Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Cc: Per Fransson <per.fransson.ml@xxxxxxxxx>
Signed-off-by: Colin Cross <ccross@xxxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
I found this thing in the Android tree, it looks like it could
be pretty serious so I'm mailing it out. If it is correct I
guess it should even be tagged for -stable?
---
 arch/arm/include/asm/hardware/cache-l2x0.h |    3 ++
 arch/arm/mm/cache-l2x0.c                   |   65 +++++++++++++++++++++++-----
 2 files changed, 57 insertions(+), 11 deletions(-)

diff --git a/arch/arm/include/asm/hardware/cache-l2x0.h b/arch/arm/include/asm/hardware/cache-l2x0.h
index c4c87bc..bd2c6a5 100644
--- a/arch/arm/include/asm/hardware/cache-l2x0.h
+++ b/arch/arm/include/asm/hardware/cache-l2x0.h
@@ -66,6 +66,7 @@
 #define   L2X0_STNDBY_MODE_EN		(1 << 0)
 
 /* Registers shifts and masks */
+#define L2X0_CACHE_ID_REV_MASK		(0x3f)
 #define L2X0_CACHE_ID_PART_MASK		(0xf << 6)
 #define L2X0_CACHE_ID_PART_L210		(1 << 6)
 #define L2X0_CACHE_ID_PART_L310		(3 << 6)
@@ -102,6 +103,8 @@
 
 #define L2X0_ADDR_FILTER_EN		1
 
+#define REV_PL310_R2P0				4
+
 #ifndef __ASSEMBLY__
 extern void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask);
 #if defined(CONFIG_CACHE_L2X0) && defined(CONFIG_OF)
diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index 2a8e380..db75e3e 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -32,6 +32,9 @@ static void __iomem *l2x0_base;
 static DEFINE_RAW_SPINLOCK(l2x0_lock);
 static u32 l2x0_way_mask;	/* Bitmask of active ways */
 static u32 l2x0_size;
+static u32 l2x0_cache_id;
+static unsigned int l2x0_sets;
+static unsigned int l2x0_ways;
 static unsigned long sync_reg_offset = L2X0_CACHE_SYNC;
 
 struct l2x0_regs l2x0_saved_regs;
@@ -42,6 +45,13 @@ struct l2x0_of_data {
 	void (*resume)(void);
 };
 
+static inline bool is_pl310_rev(int rev)
+{
+	return (l2x0_cache_id &
+		(L2X0_CACHE_ID_PART_MASK | L2X0_CACHE_ID_REV_MASK)) ==
+			(L2X0_CACHE_ID_PART_L310 | rev);
+}
+
 static inline void cache_wait_way(void __iomem *reg, unsigned long mask)
 {
 	/* wait for cache operation by line or way to complete */
@@ -130,6 +140,23 @@ static void l2x0_cache_sync(void)
 	raw_spin_unlock_irqrestore(&l2x0_lock, flags);
 }
 
+#ifdef CONFIG_PL310_ERRATA_727915
+static void l2x0_for_each_set_way(void __iomem *reg)
+{
+	int set;
+	int way;
+	unsigned long flags;
+
+	for (way = 0; way < l2x0_ways; way++) {
+		raw_spin_lock_irqsave(&l2x0_lock, flags);
+		for (set = 0; set < l2x0_sets; set++)
+			writel_relaxed((way << 28) | (set << 5), reg);
+		cache_sync();
+		raw_spin_unlock_irqrestore(&l2x0_lock, flags);
+	}
+}
+#endif
+
 static void __l2x0_flush_all(void)
 {
 	debug_writel(0x03);
@@ -143,6 +170,13 @@ static void l2x0_flush_all(void)
 {
 	unsigned long flags;
 
+#ifdef CONFIG_PL310_ERRATA_727915
+	if (is_pl310_rev(REV_PL310_R2P0)) {
+		l2x0_for_each_set_way(l2x0_base + L2X0_CLEAN_INV_LINE_IDX);
+		return;
+	}
+#endif
+
 	/* clean all ways */
 	raw_spin_lock_irqsave(&l2x0_lock, flags);
 	__l2x0_flush_all();
@@ -153,11 +187,20 @@ static void l2x0_clean_all(void)
 {
 	unsigned long flags;
 
+#ifdef CONFIG_PL310_ERRATA_727915
+	if (is_pl310_rev(REV_PL310_R2P0)) {
+		l2x0_for_each_set_way(l2x0_base + L2X0_CLEAN_LINE_IDX);
+		return;
+	}
+#endif
+
 	/* clean all ways */
 	raw_spin_lock_irqsave(&l2x0_lock, flags);
+	debug_writel(0x03);
 	writel_relaxed(l2x0_way_mask, l2x0_base + L2X0_CLEAN_WAY);
 	cache_wait_way(l2x0_base + L2X0_CLEAN_WAY, l2x0_way_mask);
 	cache_sync();
+	debug_writel(0x00);
 	raw_spin_unlock_irqrestore(&l2x0_lock, flags);
 }
 
@@ -309,26 +352,24 @@ static void l2x0_unlock(u32 cache_id)
 void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
 {
 	u32 aux;
-	u32 cache_id;
 	u32 way_size = 0;
-	int ways;
 	const char *type;
 
 	l2x0_base = base;
 
-	cache_id = readl_relaxed(l2x0_base + L2X0_CACHE_ID);
+	l2x0_cache_id = readl_relaxed(l2x0_base + L2X0_CACHE_ID);
 	aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
 
 	aux &= aux_mask;
 	aux |= aux_val;
 
 	/* Determine the number of ways */
-	switch (cache_id & L2X0_CACHE_ID_PART_MASK) {
+	switch (l2x0_cache_id & L2X0_CACHE_ID_PART_MASK) {
 	case L2X0_CACHE_ID_PART_L310:
 		if (aux & (1 << 16))
-			ways = 16;
+			l2x0_ways = 16;
 		else
-			ways = 8;
+			l2x0_ways = 8;
 		type = "L310";
 #ifdef CONFIG_PL310_ERRATA_753970
 		/* Unmapped register. */
@@ -337,7 +378,7 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
 		outer_cache.set_debug = pl310_set_debug;
 		break;
 	case L2X0_CACHE_ID_PART_L210:
-		ways = (aux >> 13) & 0xf;
+		l2x0_ways = (aux >> 13) & 0xf;
 		type = "L210";
 		break;
 	default:
@@ -347,13 +388,15 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
 		break;
 	}
 
-	l2x0_way_mask = (1 << ways) - 1;
+	l2x0_way_mask = (1 << l2x0_ways) - 1;
 
 	/*
 	 * L2 cache Size =  Way size * Number of ways
 	 */
 	way_size = (aux & L2X0_AUX_CTRL_WAY_SIZE_MASK) >> 17;
-	way_size = 1 << (way_size + 3);
+	way_size = SZ_1K << (way_size + 3);
+	l2x0_size = l2x0_ways * way_size;
+	l2x0_sets = way_size / CACHE_LINE_SIZE;
 	l2x0_size = ways * way_size * SZ_1K;
 
 	/*
@@ -363,7 +406,7 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
 	 */
 	if (!(readl_relaxed(l2x0_base + L2X0_CTRL) & 1)) {
 		/* Make sure that I&D is not locked down when starting */
-		l2x0_unlock(cache_id);
+		l2x0_unlock(l2x0_cache_id);
 
 		/* l2x0 controller is disabled */
 		writel_relaxed(aux, l2x0_base + L2X0_AUX_CTRL);
@@ -386,7 +429,7 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
 
 	printk(KERN_INFO "%s cache controller enabled\n", type);
 	printk(KERN_INFO "l2x0: %d ways, CACHE_ID 0x%08x, AUX_CTRL 0x%08x, Cache size: %d B\n",
-			ways, cache_id, aux, l2x0_size);
+			l2x0_ways, l2x0_cache_id, aux, l2x0_size);
 }
 
 #ifdef CONFIG_OF
-- 
1.7.9.2


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