4 files changed, 36 insertions, 0 deletions

diff --git a/arch/sparc64/kernel/setup.c b/arch/sparc64/kernel/setup.c
index 12c3d84b7460..b7e6a91952b2 100644
--- a/arch/sparc64/kernel/setup.c
+++ b/arch/sparc64/kernel/setup.c
@@ -383,6 +383,17 @@ static void __init process_switch(char c)
                 /* Use PROM debug console. */
                 register_console(&prom_debug_console);
                 break;
+        case 'P':
+                /* Force UltraSPARC-III P-Cache on. */
+                if (tlb_type != cheetah) {
+                        printk("BOOT: Ignoring P-Cache force option.\n");
+                        break;
+                }
+                cheetah_pcache_forced_on = 1;
+                add_taint(TAINT_MACHINE_CHECK);
+                cheetah_enable_pcache();
+                break;
+
         default:
                 printk("Unknown boot switch (-%c)\n", c);
                 break;
diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index 6dff06a44e76..e5b9c7a27789 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -123,6 +123,9 @@ void __init smp_callin(void)
 
         smp_setup_percpu_timer();
 
+        if (cheetah_pcache_forced_on)
+                cheetah_enable_pcache();
+
         local_irq_enable();
 
         calibrate_delay();
diff --git a/arch/sparc64/kernel/traps.c b/arch/sparc64/kernel/traps.c
index 56b203a2af69..a9f4596d7c2b 100644
--- a/arch/sparc64/kernel/traps.c
+++ b/arch/sparc64/kernel/traps.c
@@ -421,6 +421,25 @@ asmlinkage void cee_log(unsigned long ce_status,
         }
 }
 
+int cheetah_pcache_forced_on;
+
+void cheetah_enable_pcache(void)
+{
+        unsigned long dcr;
+
+        printk("CHEETAH: Enabling P-Cache on cpu %d.\n",
+               smp_processor_id());
+
+        __asm__ __volatile__("ldxa [%%g0] %1, %0"
+                             : "=r" (dcr)
+                             : "i" (ASI_DCU_CONTROL_REG));
+        dcr |= (DCU_PE | DCU_HPE | DCU_SPE | DCU_SL);
+        __asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
+                             "membar #Sync"
+                             : /* no outputs */
+                             : "r" (dcr), "i" (ASI_DCU_CONTROL_REG));
+}
+
 /* Cheetah error trap handling. */
 static unsigned long ecache_flush_physbase;
 static unsigned long ecache_flush_linesize;
diff --git a/include/asm-sparc64/spitfire.h b/include/asm-sparc64/spitfire.h
index ad78ce64d69e..9d7613eea812 100644
--- a/include/asm-sparc64/spitfire.h
+++ b/include/asm-sparc64/spitfire.h
@@ -48,6 +48,9 @@ enum ultra_tlb_layout {
 
 extern enum ultra_tlb_layout tlb_type;
 
+extern int cheetah_pcache_forced_on;
+extern void cheetah_enable_pcache(void);
+
 #define sparc64_highest_locked_tlbent() \
         (tlb_type == spitfire ? \
          SPITFIRE_HIGHEST_LOCKED_TLBENT : \