sh: Kill off segment-based d-cache flushing on SH-4.
This kills off the unrolled segment based flushers on SH-4 and switches
over to a generic unrolled approach derived from the writethrough segment
flusher.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c
index f099960..92b7d94 100644
--- a/arch/sh/mm/cache-sh4.c
+++ b/arch/sh/mm/cache-sh4.c
@@ -30,14 +30,6 @@
unsigned long exec_offset);
/*
- * This is initialised here to ensure that it is not placed in the BSS. If
- * that were to happen, note that cache_init gets called before the BSS is
- * cleared, so this would get nulled out which would be hopeless.
- */
-static void (*__flush_dcache_segment_fn)(unsigned long, unsigned long) =
- (void (*)(unsigned long, unsigned long))0xdeadbeef;
-
-/*
* Write back the range of D-cache, and purge the I-cache.
*
* Called from kernel/module.c:sys_init_module and routine for a.out format,
@@ -158,10 +150,27 @@
local_irq_restore(flags);
}
-static inline void flush_dcache_all(void)
+static void flush_dcache_all(void)
{
- (*__flush_dcache_segment_fn)(0UL, boot_cpu_data.dcache.way_size);
- wmb();
+ unsigned long addr, end_addr, entry_offset;
+
+ end_addr = CACHE_OC_ADDRESS_ARRAY +
+ (current_cpu_data.dcache.sets <<
+ current_cpu_data.dcache.entry_shift) *
+ current_cpu_data.dcache.ways;
+
+ entry_offset = 1 << current_cpu_data.dcache.entry_shift;
+
+ for (addr = CACHE_OC_ADDRESS_ARRAY; addr < end_addr; ) {
+ __raw_writel(0, addr); addr += entry_offset;
+ __raw_writel(0, addr); addr += entry_offset;
+ __raw_writel(0, addr); addr += entry_offset;
+ __raw_writel(0, addr); addr += entry_offset;
+ __raw_writel(0, addr); addr += entry_offset;
+ __raw_writel(0, addr); addr += entry_offset;
+ __raw_writel(0, addr); addr += entry_offset;
+ __raw_writel(0, addr); addr += entry_offset;
+ }
}
static void sh4_flush_cache_all(void *unused)
@@ -347,245 +356,6 @@
} while (--way_count != 0);
}
-/*
- * Break the 1, 2 and 4 way variants of this out into separate functions to
- * avoid nearly all the overhead of having the conditional stuff in the function
- * bodies (+ the 1 and 2 way cases avoid saving any registers too).
- *
- * We want to eliminate unnecessary bus transactions, so this code uses
- * a non-obvious technique.
- *
- * Loop over a cache way sized block of, one cache line at a time. For each
- * line, use movca.a to cause the current cache line contents to be written
- * back, but without reading anything from main memory. However this has the
- * side effect that the cache is now caching that memory location. So follow
- * this with a cache invalidate to mark the cache line invalid. And do all
- * this with interrupts disabled, to avoid the cache line being accidently
- * evicted while it is holding garbage.
- *
- * This also breaks in a number of circumstances:
- * - if there are modifications to the region of memory just above
- * empty_zero_page (for example because a breakpoint has been placed
- * there), then these can be lost.
- *
- * This is because the the memory address which the cache temporarily
- * caches in the above description is empty_zero_page. So the
- * movca.l hits the cache (it is assumed that it misses, or at least
- * isn't dirty), modifies the line and then invalidates it, losing the
- * required change.
- *
- * - If caches are disabled or configured in write-through mode, then
- * the movca.l writes garbage directly into memory.
- */
-static void __flush_dcache_segment_writethrough(unsigned long start,
- unsigned long extent_per_way)
-{
- unsigned long addr;
- int i;
-
- addr = CACHE_OC_ADDRESS_ARRAY | (start & cpu_data->dcache.entry_mask);
-
- while (extent_per_way) {
- for (i = 0; i < cpu_data->dcache.ways; i++)
- __raw_writel(0, addr + cpu_data->dcache.way_incr * i);
-
- addr += cpu_data->dcache.linesz;
- extent_per_way -= cpu_data->dcache.linesz;
- }
-}
-
-static void __flush_dcache_segment_1way(unsigned long start,
- unsigned long extent_per_way)
-{
- unsigned long orig_sr, sr_with_bl;
- unsigned long base_addr;
- unsigned long way_incr, linesz, way_size;
- struct cache_info *dcache;
- register unsigned long a0, a0e;
-
- asm volatile("stc sr, %0" : "=r" (orig_sr));
- sr_with_bl = orig_sr | (1<<28);
- base_addr = ((unsigned long)&empty_zero_page[0]);
-
- /*
- * The previous code aligned base_addr to 16k, i.e. the way_size of all
- * existing SH-4 D-caches. Whilst I don't see a need to have this
- * aligned to any better than the cache line size (which it will be
- * anyway by construction), let's align it to at least the way_size of
- * any existing or conceivable SH-4 D-cache. -- RPC
- */
- base_addr = ((base_addr >> 16) << 16);
- base_addr |= start;
-
- dcache = &boot_cpu_data.dcache;
- linesz = dcache->linesz;
- way_incr = dcache->way_incr;
- way_size = dcache->way_size;
-
- a0 = base_addr;
- a0e = base_addr + extent_per_way;
- do {
- asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
- asm volatile("movca.l r0, @%0\n\t"
- "ocbi @%0" : : "r" (a0));
- a0 += linesz;
- asm volatile("movca.l r0, @%0\n\t"
- "ocbi @%0" : : "r" (a0));
- a0 += linesz;
- asm volatile("movca.l r0, @%0\n\t"
- "ocbi @%0" : : "r" (a0));
- a0 += linesz;
- asm volatile("movca.l r0, @%0\n\t"
- "ocbi @%0" : : "r" (a0));
- asm volatile("ldc %0, sr" : : "r" (orig_sr));
- a0 += linesz;
- } while (a0 < a0e);
-}
-
-static void __flush_dcache_segment_2way(unsigned long start,
- unsigned long extent_per_way)
-{
- unsigned long orig_sr, sr_with_bl;
- unsigned long base_addr;
- unsigned long way_incr, linesz, way_size;
- struct cache_info *dcache;
- register unsigned long a0, a1, a0e;
-
- asm volatile("stc sr, %0" : "=r" (orig_sr));
- sr_with_bl = orig_sr | (1<<28);
- base_addr = ((unsigned long)&empty_zero_page[0]);
-
- /* See comment under 1-way above */
- base_addr = ((base_addr >> 16) << 16);
- base_addr |= start;
-
- dcache = &boot_cpu_data.dcache;
- linesz = dcache->linesz;
- way_incr = dcache->way_incr;
- way_size = dcache->way_size;
-
- a0 = base_addr;
- a1 = a0 + way_incr;
- a0e = base_addr + extent_per_way;
- do {
- asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
- asm volatile("movca.l r0, @%0\n\t"
- "movca.l r0, @%1\n\t"
- "ocbi @%0\n\t"
- "ocbi @%1" : :
- "r" (a0), "r" (a1));
- a0 += linesz;
- a1 += linesz;
- asm volatile("movca.l r0, @%0\n\t"
- "movca.l r0, @%1\n\t"
- "ocbi @%0\n\t"
- "ocbi @%1" : :
- "r" (a0), "r" (a1));
- a0 += linesz;
- a1 += linesz;
- asm volatile("movca.l r0, @%0\n\t"
- "movca.l r0, @%1\n\t"
- "ocbi @%0\n\t"
- "ocbi @%1" : :
- "r" (a0), "r" (a1));
- a0 += linesz;
- a1 += linesz;
- asm volatile("movca.l r0, @%0\n\t"
- "movca.l r0, @%1\n\t"
- "ocbi @%0\n\t"
- "ocbi @%1" : :
- "r" (a0), "r" (a1));
- asm volatile("ldc %0, sr" : : "r" (orig_sr));
- a0 += linesz;
- a1 += linesz;
- } while (a0 < a0e);
-}
-
-static void __flush_dcache_segment_4way(unsigned long start,
- unsigned long extent_per_way)
-{
- unsigned long orig_sr, sr_with_bl;
- unsigned long base_addr;
- unsigned long way_incr, linesz, way_size;
- struct cache_info *dcache;
- register unsigned long a0, a1, a2, a3, a0e;
-
- asm volatile("stc sr, %0" : "=r" (orig_sr));
- sr_with_bl = orig_sr | (1<<28);
- base_addr = ((unsigned long)&empty_zero_page[0]);
-
- /* See comment under 1-way above */
- base_addr = ((base_addr >> 16) << 16);
- base_addr |= start;
-
- dcache = &boot_cpu_data.dcache;
- linesz = dcache->linesz;
- way_incr = dcache->way_incr;
- way_size = dcache->way_size;
-
- a0 = base_addr;
- a1 = a0 + way_incr;
- a2 = a1 + way_incr;
- a3 = a2 + way_incr;
- a0e = base_addr + extent_per_way;
- do {
- asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
- asm volatile("movca.l r0, @%0\n\t"
- "movca.l r0, @%1\n\t"
- "movca.l r0, @%2\n\t"
- "movca.l r0, @%3\n\t"
- "ocbi @%0\n\t"
- "ocbi @%1\n\t"
- "ocbi @%2\n\t"
- "ocbi @%3\n\t" : :
- "r" (a0), "r" (a1), "r" (a2), "r" (a3));
- a0 += linesz;
- a1 += linesz;
- a2 += linesz;
- a3 += linesz;
- asm volatile("movca.l r0, @%0\n\t"
- "movca.l r0, @%1\n\t"
- "movca.l r0, @%2\n\t"
- "movca.l r0, @%3\n\t"
- "ocbi @%0\n\t"
- "ocbi @%1\n\t"
- "ocbi @%2\n\t"
- "ocbi @%3\n\t" : :
- "r" (a0), "r" (a1), "r" (a2), "r" (a3));
- a0 += linesz;
- a1 += linesz;
- a2 += linesz;
- a3 += linesz;
- asm volatile("movca.l r0, @%0\n\t"
- "movca.l r0, @%1\n\t"
- "movca.l r0, @%2\n\t"
- "movca.l r0, @%3\n\t"
- "ocbi @%0\n\t"
- "ocbi @%1\n\t"
- "ocbi @%2\n\t"
- "ocbi @%3\n\t" : :
- "r" (a0), "r" (a1), "r" (a2), "r" (a3));
- a0 += linesz;
- a1 += linesz;
- a2 += linesz;
- a3 += linesz;
- asm volatile("movca.l r0, @%0\n\t"
- "movca.l r0, @%1\n\t"
- "movca.l r0, @%2\n\t"
- "movca.l r0, @%3\n\t"
- "ocbi @%0\n\t"
- "ocbi @%1\n\t"
- "ocbi @%2\n\t"
- "ocbi @%3\n\t" : :
- "r" (a0), "r" (a1), "r" (a2), "r" (a3));
- asm volatile("ldc %0, sr" : : "r" (orig_sr));
- a0 += linesz;
- a1 += linesz;
- a2 += linesz;
- a3 += linesz;
- } while (a0 < a0e);
-}
-
extern void __weak sh4__flush_region_init(void);
/*
@@ -593,32 +363,11 @@
*/
void __init sh4_cache_init(void)
{
- unsigned int wt_enabled = !!(__raw_readl(CCR) & CCR_CACHE_WT);
-
printk("PVR=%08x CVR=%08x PRR=%08x\n",
ctrl_inl(CCN_PVR),
ctrl_inl(CCN_CVR),
ctrl_inl(CCN_PRR));
- if (wt_enabled)
- __flush_dcache_segment_fn = __flush_dcache_segment_writethrough;
- else {
- switch (boot_cpu_data.dcache.ways) {
- case 1:
- __flush_dcache_segment_fn = __flush_dcache_segment_1way;
- break;
- case 2:
- __flush_dcache_segment_fn = __flush_dcache_segment_2way;
- break;
- case 4:
- __flush_dcache_segment_fn = __flush_dcache_segment_4way;
- break;
- default:
- panic("unknown number of cache ways\n");
- break;
- }
- }
-
local_flush_icache_range = sh4_flush_icache_range;
local_flush_dcache_page = sh4_flush_dcache_page;
local_flush_cache_all = sh4_flush_cache_all;