sh: sh2a: Improve cache flush/invalidate functions

The cache functions lock out interrupts for long periods; this patch
reduces the impact when operating on large address ranges. In such
cases it will:
- Invalidate the entire cache rather than individual addresses.
- Do nothing when flushing the operand cache in write-through mode.
- When flushing the operand cache in write-back mdoe, index the
  search for matching addresses on the cache entires instead of the
  addresses to flush

Note: sh2a__flush_purge_region was only invalidating the operand
cache, this adds flush.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 84 insertions, 39 deletions

diff --git a/arch/sh/mm/cache-sh2a.c b/arch/sh/mm/cache-sh2a.c
index 1f51225426a2..ae08cbbfa569 100644
--- a/arch/sh/mm/cache-sh2a.c
+++ b/arch/sh/mm/cache-sh2a.c
@@ -15,35 +15,78 @@
 #include <asm/cacheflush.h>
 #include <asm/io.h>
 
+/*
+ * The maximum number of pages we support up to when doing ranged dcache
+ * flushing. Anything exceeding this will simply flush the dcache in its
+ * entirety.
+ */
+#define MAX_OCACHE_PAGES        32
+#define MAX_ICACHE_PAGES        32
+
+static void sh2a_flush_oc_line(unsigned long v, int way)
+{
+        unsigned long addr = (v & 0x000007f0) | (way << 11);
+        unsigned long data;
+
+        data = __raw_readl(CACHE_OC_ADDRESS_ARRAY | addr);
+        if ((data & CACHE_PHYSADDR_MASK) == (v & CACHE_PHYSADDR_MASK)) {
+                data &= ~SH_CACHE_UPDATED;
+                __raw_writel(data, CACHE_OC_ADDRESS_ARRAY | addr);
+        }
+}
+
+static void sh2a_invalidate_line(unsigned long cache_addr, unsigned long v)
+{
+        /* Set associative bit to hit all ways */
+        unsigned long addr = (v & 0x000007f0) | SH_CACHE_ASSOC;
+        __raw_writel((addr & CACHE_PHYSADDR_MASK), cache_addr | addr);
+}
+
+/*
+ * Write back the dirty D-caches, but not invalidate them.
+ */
 static void sh2a__flush_wback_region(void *start, int size)
 {
+#ifdef CONFIG_CACHE_WRITEBACK
         unsigned long v;
         unsigned long begin, end;
         unsigned long flags;
+        int nr_ways;
 
         begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
         end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
                 & ~(L1_CACHE_BYTES-1);
+        nr_ways = current_cpu_data.dcache.ways;
 
         local_irq_save(flags);
         jump_to_uncached();
 
-        for (v = begin; v < end; v+=L1_CACHE_BYTES) {
-                unsigned long addr = CACHE_OC_ADDRESS_ARRAY | (v & 0x000007f0);
+        /* If there are too many pages then flush the entire cache */
+        if (((end - begin) >> PAGE_SHIFT) >= MAX_OCACHE_PAGES) {
+                begin = CACHE_OC_ADDRESS_ARRAY;
+                end = begin + (nr_ways * current_cpu_data.dcache.way_size);
+
+                for (v = begin; v < end; v += L1_CACHE_BYTES) {
+                        unsigned long data = __raw_readl(v);
+                        if (data & SH_CACHE_UPDATED)
+                                __raw_writel(data & ~SH_CACHE_UPDATED, v);
+                }
+        } else {
                 int way;
-                for (way = 0; way < 4; way++) {
-                        unsigned long data =  __raw_readl(addr | (way << 11));
-                        if ((data & CACHE_PHYSADDR_MASK) == (v & CACHE_PHYSADDR_MASK)) {
-                                data &= ~SH_CACHE_UPDATED;
-                                __raw_writel(data, addr | (way << 11));
-                        }
+                for (way = 0; way < nr_ways; way++) {
+                        for (v = begin; v < end; v += L1_CACHE_BYTES)
+                                sh2a_flush_oc_line(v, way);
                 }
         }
 
         back_to_cached();
         local_irq_restore(flags);
+#endif
 }
 
+/*
+ * Write back the dirty D-caches and invalidate them.
+ */
 static void sh2a__flush_purge_region(void *start, int size)
 {
         unsigned long v;
@@ -58,13 +101,22 @@ static void sh2a__flush_purge_region(void *start, int size)
         jump_to_uncached();
 
         for (v = begin; v < end; v+=L1_CACHE_BYTES) {
-                __raw_writel((v & CACHE_PHYSADDR_MASK),
-                          CACHE_OC_ADDRESS_ARRAY | (v & 0x000007f0) | 0x00000008);
+#ifdef CONFIG_CACHE_WRITEBACK
+                int way;
+                int nr_ways = current_cpu_data.dcache.ways;
+                for (way = 0; way < nr_ways; way++)
+                        sh2a_flush_oc_line(v, way);
+#endif
+                sh2a_invalidate_line(CACHE_OC_ADDRESS_ARRAY, v);
         }
+
         back_to_cached();
         local_irq_restore(flags);
 }
 
+/*
+ * Invalidate the D-caches, but no write back please
+ */
 static void sh2a__flush_invalidate_region(void *start, int size)
 {
         unsigned long v;
@@ -74,29 +126,25 @@ static void sh2a__flush_invalidate_region(void *start, int size)
         begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
         end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
                 & ~(L1_CACHE_BYTES-1);
+
         local_irq_save(flags);
         jump_to_uncached();
 
-#ifdef CONFIG_CACHE_WRITEBACK
-        __raw_writel(__raw_readl(CCR) | CCR_OCACHE_INVALIDATE, CCR);
-        /* I-cache invalidate */
-        for (v = begin; v < end; v+=L1_CACHE_BYTES) {
-                __raw_writel((v & CACHE_PHYSADDR_MASK),
-                          CACHE_IC_ADDRESS_ARRAY | (v & 0x000007f0) | 0x00000008);
-        }
-#else
-        for (v = begin; v < end; v+=L1_CACHE_BYTES) {
-                __raw_writel((v & CACHE_PHYSADDR_MASK),
-                          CACHE_IC_ADDRESS_ARRAY | (v & 0x000007f0) | 0x00000008);
-                __raw_writel((v & CACHE_PHYSADDR_MASK),
-                          CACHE_OC_ADDRESS_ARRAY | (v & 0x000007f0) | 0x00000008);
+        /* If there are too many pages then just blow the cache */
+        if (((end - begin) >> PAGE_SHIFT) >= MAX_OCACHE_PAGES) {
+                __raw_writel(__raw_readl(CCR) | CCR_OCACHE_INVALIDATE, CCR);
+        } else {
+                for (v = begin; v < end; v += L1_CACHE_BYTES)
+                        sh2a_invalidate_line(CACHE_OC_ADDRESS_ARRAY, v);
         }
-#endif
+
         back_to_cached();
         local_irq_restore(flags);
 }
 
-/* WBack O-Cache and flush I-Cache */
+/*
+ * Write back the range of D-cache, and purge the I-cache.
+ */
 static void sh2a_flush_icache_range(void *args)
 {
         struct flusher_data *data = args;
@@ -107,23 +155,20 @@ static void sh2a_flush_icache_range(void *args)
         start = data->addr1 & ~(L1_CACHE_BYTES-1);
         end = (data->addr2 + L1_CACHE_BYTES-1) & ~(L1_CACHE_BYTES-1);
 
+#ifdef CONFIG_CACHE_WRITEBACK
+        sh2a__flush_wback_region((void *)start, end-start);
+#endif
+
         local_irq_save(flags);
         jump_to_uncached();
 
-        for (v = start; v < end; v+=L1_CACHE_BYTES) {
-                unsigned long addr = (v & 0x000007f0);
-                int way;
-                /* O-Cache writeback */
-                for (way = 0; way < 4; way++) {
-                        unsigned long data =  __raw_readl(CACHE_OC_ADDRESS_ARRAY | addr | (way << 11));
-                        if ((data & CACHE_PHYSADDR_MASK) == (v & CACHE_PHYSADDR_MASK)) {
-                                data &= ~SH_CACHE_UPDATED;
-                                __raw_writel(data, CACHE_OC_ADDRESS_ARRAY | addr | (way << 11));
-                        }
-                }
-                /* I-Cache invalidate */
-                __raw_writel(addr,
-                          CACHE_IC_ADDRESS_ARRAY | addr | 0x00000008);
+        /* I-Cache invalidate */
+        /* If there are too many pages then just blow the cache */
+        if (((end - start) >> PAGE_SHIFT) >= MAX_ICACHE_PAGES) {
+                __raw_writel(__raw_readl(CCR) | CCR_ICACHE_INVALIDATE, CCR);
+        } else {
+                for (v = start; v < end; v += L1_CACHE_BYTES)
+                        sh2a_invalidate_line(CACHE_IC_ADDRESS_ARRAY, v);
         }
 
         back_to_cached();