[MIPS] Fix handling of 0 length I & D caches.

Don't ask.
Signed-off-by: Chris Dearman <chris@mips.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/mm/c-r4k.c

@@ -60,13 +60,13 @@ static unsigned long scache_size __read_mostly;
 /*
  * Dummy cache handling routines for machines without boardcaches
  */
-static void no_sc_noop(void) {}
+static void cache_noop(void) {}
 
 static struct bcache_ops no_sc_ops = {
-	.bc_enable = (void *)no_sc_noop,
-	.bc_disable = (void *)no_sc_noop,
-	.bc_wback_inv = (void *)no_sc_noop,
-	.bc_inv = (void *)no_sc_noop
+	.bc_enable = (void *)cache_noop,
+	.bc_disable = (void *)cache_noop,
+	.bc_wback_inv = (void *)cache_noop,
+	.bc_inv = (void *)cache_noop
 };
 
 struct bcache_ops *bcops = &no_sc_ops;
@@ -94,7 +94,9 @@ static inline void r4k_blast_dcache_page_setup(void)
 {
 	unsigned long  dc_lsize = cpu_dcache_line_size();
 
-	if (dc_lsize == 16)
+	if (dc_lsize == 0)
+		r4k_blast_dcache_page = (void *)cache_noop;
+	else if (dc_lsize == 16)
 		r4k_blast_dcache_page = blast_dcache16_page;
 	else if (dc_lsize == 32)
 		r4k_blast_dcache_page = r4k_blast_dcache_page_dc32;
@@ -106,7 +108,9 @@ static inline void r4k_blast_dcache_page_indexed_setup(void)
 {
 	unsigned long dc_lsize = cpu_dcache_line_size();
 
-	if (dc_lsize == 16)
+	if (dc_lsize == 0)
+		r4k_blast_dcache_page_indexed = (void *)cache_noop;
+	else if (dc_lsize == 16)
 		r4k_blast_dcache_page_indexed = blast_dcache16_page_indexed;
 	else if (dc_lsize == 32)
 		r4k_blast_dcache_page_indexed = blast_dcache32_page_indexed;
@@ -118,7 +122,9 @@ static inline void r4k_blast_dcache_setup(void)
 {
 	unsigned long dc_lsize = cpu_dcache_line_size();
 
-	if (dc_lsize == 16)
+	if (dc_lsize == 0)
+		r4k_blast_dcache = (void *)cache_noop;
+	else if (dc_lsize == 16)
 		r4k_blast_dcache = blast_dcache16;
 	else if (dc_lsize == 32)
 		r4k_blast_dcache = blast_dcache32;
@@ -201,7 +207,9 @@ static inline void r4k_blast_icache_page_setup(void)
 {
 	unsigned long ic_lsize = cpu_icache_line_size();
 
-	if (ic_lsize == 16)
+	if (ic_lsize == 0)
+		r4k_blast_icache_page = (void *)cache_noop;
+	else if (ic_lsize == 16)
 		r4k_blast_icache_page = blast_icache16_page;
 	else if (ic_lsize == 32)
 		r4k_blast_icache_page = blast_icache32_page;
@@ -216,7 +224,9 @@ static inline void r4k_blast_icache_page_indexed_setup(void)
 {
 	unsigned long ic_lsize = cpu_icache_line_size();
 
-	if (ic_lsize == 16)
+	if (ic_lsize == 0)
+		r4k_blast_icache_page_indexed = (void *)cache_noop;
+	else if (ic_lsize == 16)
 		r4k_blast_icache_page_indexed = blast_icache16_page_indexed;
 	else if (ic_lsize == 32) {
 		if (R4600_V1_INDEX_ICACHEOP_WAR && cpu_is_r4600_v1_x())
@@ -238,7 +248,9 @@ static inline void r4k_blast_icache_setup(void)
 {
 	unsigned long ic_lsize = cpu_icache_line_size();
 
-	if (ic_lsize == 16)
+	if (ic_lsize == 0)
+		r4k_blast_icache = (void *)cache_noop;
+	else if (ic_lsize == 16)
 		r4k_blast_icache = blast_icache16;
 	else if (ic_lsize == 32) {
 		if (R4600_V1_INDEX_ICACHEOP_WAR && cpu_is_r4600_v1_x())
@@ -258,7 +270,7 @@ static inline void r4k_blast_scache_page_setup(void)
 	unsigned long sc_lsize = cpu_scache_line_size();
 
 	if (scache_size == 0)
-		r4k_blast_scache_page = (void *)no_sc_noop;
+		r4k_blast_scache_page = (void *)cache_noop;
 	else if (sc_lsize == 16)
 		r4k_blast_scache_page = blast_scache16_page;
 	else if (sc_lsize == 32)
@@ -276,7 +288,7 @@ static inline void r4k_blast_scache_page_indexed_setup(void)
 	unsigned long sc_lsize = cpu_scache_line_size();
 
 	if (scache_size == 0)
-		r4k_blast_scache_page_indexed = (void *)no_sc_noop;
+		r4k_blast_scache_page_indexed = (void *)cache_noop;
 	else if (sc_lsize == 16)
 		r4k_blast_scache_page_indexed = blast_scache16_page_indexed;
 	else if (sc_lsize == 32)
@@ -294,7 +306,7 @@ static inline void r4k_blast_scache_setup(void)
 	unsigned long sc_lsize = cpu_scache_line_size();
 
 	if (scache_size == 0)
-		r4k_blast_scache = (void *)no_sc_noop;
+		r4k_blast_scache = (void *)cache_noop;
 	else if (sc_lsize == 16)
 		r4k_blast_scache = blast_scache16;
 	else if (sc_lsize == 32)
@@ -508,7 +520,7 @@ static inline void local_r4k_flush_icache_range(void *args)
 	unsigned long end = fir_args->end;
 
 	if (!cpu_has_ic_fills_f_dc) {
-		if (end - start > dcache_size) {
+		if (end - start >= dcache_size) {
 			r4k_blast_dcache();
 		} else {
 			R4600_HIT_CACHEOP_WAR_IMPL;
@@ -683,9 +695,11 @@ static void local_r4k_flush_cache_sigtramp(void * arg)
 	unsigned long addr = (unsigned long) arg;
 
 	R4600_HIT_CACHEOP_WAR_IMPL;
+	if (dc_lsize)
 		protected_writeback_dcache_line(addr & ~(dc_lsize - 1));
 	if (!cpu_icache_snoops_remote_store && scache_size)
 		protected_writeback_scache_line(addr & ~(sc_lsize - 1));
+	if (ic_lsize)
 		protected_flush_icache_line(addr & ~(ic_lsize - 1));
 	if (MIPS4K_ICACHE_REFILL_WAR) {
 		__asm__ __volatile__ (
@@ -973,8 +987,10 @@ static void __init probe_pcache(void)
 	c->icache.waysize = icache_size / c->icache.ways;
 	c->dcache.waysize = dcache_size / c->dcache.ways;
 
-	c->icache.sets = icache_size / (c->icache.linesz * c->icache.ways);
-	c->dcache.sets = dcache_size / (c->dcache.linesz * c->dcache.ways);
+	c->icache.sets = c->icache.linesz ?
+		icache_size / (c->icache.linesz * c->icache.ways) : 0;
+	c->dcache.sets = c->dcache.linesz ?
+		dcache_size / (c->dcache.linesz * c->dcache.ways) : 0;
 
 	/*
 	 * R10000 and R12000 P-caches are odd in a positive way.  They're 32kB
@@ -1259,10 +1275,12 @@ void __init r4k_cache_init(void)
 	 * This code supports virtually indexed processors and will be
 	 * unnecessarily inefficient on physically indexed processors.
 	 */
+	if (c->dcache.linesz)
 		shm_align_mask = max_t( unsigned long,
 					c->dcache.sets * c->dcache.linesz - 1,
 					PAGE_SIZE - 1);
-
+	else
+		shm_align_mask = PAGE_SIZE-1;
 	flush_cache_all		= r4k_flush_cache_all;
 	__flush_cache_all	= r4k___flush_cache_all;
 	flush_cache_mm		= r4k_flush_cache_mm;