[ARM] tegra: SMP support

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Erik Gilling <konkers@android.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/headsmp.S b/arch/arm/mach-tegra/headsmp.S
new file mode 100644
index 000000000000..b5349b2f13d2
--- /dev/null
+++ b/arch/arm/mach-tegra/headsmp.S
@@ -0,0 +1,61 @@
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+        .section ".text.head", "ax"
+        __CPUINIT
+
+/*
+ * Tegra specific entry point for secondary CPUs.
+ *   The secondary kernel init calls v7_flush_dcache_all before it enables
+ *   the L1; however, the L1 comes out of reset in an undefined state, so
+ *   the clean + invalidate performed by v7_flush_dcache_all causes a bunch
+ *   of cache lines with uninitialized data and uninitialized tags to get
+ *   written out to memory, which does really unpleasant things to the main
+ *   processor.  We fix this by performing an invalidate, rather than a
+ *   clean + invalidate, before jumping into the kernel.
+ */
+ENTRY(v7_invalidate_l1)
+        mov     r0, #0
+        mcr     p15, 2, r0, c0, c0, 0
+        mrc     p15, 1, r0, c0, c0, 0
+
+        ldr     r1, =0x7fff
+        and     r2, r1, r0, lsr #13
+
+        ldr     r1, =0x3ff
+
+        and     r3, r1, r0, lsr #3  @ NumWays - 1
+        add     r2, r2, #1          @ NumSets
+
+        and     r0, r0, #0x7
+        add     r0, r0, #4          @ SetShift
+
+        clz     r1, r3              @ WayShift
+        add     r4, r3, #1          @ NumWays
+1:      sub     r2, r2, #1          @ NumSets--
+        mov     r3, r4              @ Temp = NumWays
+2:      subs    r3, r3, #1          @ Temp--
+        mov     r5, r3, lsl r1
+        mov     r6, r2, lsl r0
+        orr     r5, r5, r6          @ Reg = (Temp<<WayShift)|(NumSets<<SetShift)
+        mcr     p15, 0, r5, c7, c6, 2
+        bgt     2b
+        cmp     r2, #0
+        bgt     1b
+        dsb
+        isb
+        mov     pc, lr
+ENDPROC(v7_invalidate_l1)
+
+ENTRY(tegra_secondary_startup)
+        msr     cpsr_fsxc, #0xd3
+        bl      v7_invalidate_l1
+        mrc     p15, 0, r0, c0, c0, 5
+        and     r0, r0, #15
+        ldr     r1, =0x6000f100
+        str     r0, [r1]
+1:      ldr     r2, [r1]
+        cmp     r0, r2
+        beq     1b
+        b       secondary_startup
+ENDPROC(tegra_secondary_startup)