From c9941158fd8a539a56b0e8a4740ec1f6beb23ea3 Mon Sep 17 00:00:00 2001 From: David Daney Date: Thu, 7 Oct 2010 16:03:53 -0700 Subject: [PATCH] MIPS: Octeon: Apply CN63XXP1 errata workarounds. The CN63XXP1 needs a couple of workarounds to ensure memory is not written in unexpected ways. All PREF with hints in the range 0-4,6-24 are replaced with PREF 28. We pass a flag to the assembler to cover compiler generated code, and patch uasm for the dynamically generated code. The write buffer threshold is reduced to 4. Signed-off-by: David Daney Patchwork: http://patchwork.linux-mips.org/patch/1672/ Signed-off-by: Ralf Baechle --- arch/mips/Makefile | 1 + arch/mips/cavium-octeon/Kconfig | 11 +++++++++ arch/mips/cavium-octeon/setup.c | 42 +++++++++++++++++++++++++++++---- arch/mips/mm/uasm.c | 20 +++++++++++++++- 4 files changed, 69 insertions(+), 5 deletions(-) diff --git a/arch/mips/Makefile b/arch/mips/Makefile index 1a81240102c5..7c1102e41fe2 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -156,6 +156,7 @@ cflags-$(CONFIG_CPU_CAVIUM_OCTEON) += $(call cc-option,-march=octeon) -Wa,--trap ifeq (,$(findstring march=octeon, $(cflags-$(CONFIG_CPU_CAVIUM_OCTEON)))) cflags-$(CONFIG_CPU_CAVIUM_OCTEON) += -Wa,-march=octeon endif +cflags-$(CONFIG_CAVIUM_CN63XXP1) += -Wa,-mfix-cn63xxp1 cflags-$(CONFIG_CPU_R4000_WORKAROUNDS) += $(call cc-option,-mfix-r4000,) cflags-$(CONFIG_CPU_R4400_WORKAROUNDS) += $(call cc-option,-mfix-r4400,) diff --git a/arch/mips/cavium-octeon/Kconfig b/arch/mips/cavium-octeon/Kconfig index 475156b0c807..caae22858163 100644 --- a/arch/mips/cavium-octeon/Kconfig +++ b/arch/mips/cavium-octeon/Kconfig @@ -3,6 +3,17 @@ config CAVIUM_OCTEON_SPECIFIC_OPTIONS depends on CPU_CAVIUM_OCTEON default "y" +config CAVIUM_CN63XXP1 + bool "Enable CN63XXP1 errata worarounds" + depends on CAVIUM_OCTEON_SPECIFIC_OPTIONS + default "n" + help + The CN63XXP1 chip requires build time workarounds to + function reliably, select this option to enable them. These + workarounds will cause a slight decrease in performance on + non-CN63XXP1 hardware, so it is recommended to select "n" + unless it is known the workarounds are needed. + config CAVIUM_OCTEON_2ND_KERNEL bool "Build the kernel to be used as a 2nd kernel on the same chip" depends on CAVIUM_OCTEON_SPECIFIC_OPTIONS diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c index c072b24f4853..b0c3686c96dd 100644 --- a/arch/mips/cavium-octeon/setup.c +++ b/arch/mips/cavium-octeon/setup.c @@ -356,8 +356,18 @@ void octeon_user_io_init(void) cvmmemctl.s.wbfltime = 0; /* R/W If set, do not put Istream in the L2 cache. */ cvmmemctl.s.istrnol2 = 0; - /* R/W The write buffer threshold. */ - cvmmemctl.s.wbthresh = 10; + + /* + * R/W The write buffer threshold. As per erratum Core-14752 + * for CN63XX, a sc/scd might fail if the write buffer is + * full. Lowering WBTHRESH greatly lowers the chances of the + * write buffer ever being full and triggering the erratum. + */ + if (OCTEON_IS_MODEL(OCTEON_CN63XX_PASS1_X)) + cvmmemctl.s.wbthresh = 4; + else + cvmmemctl.s.wbthresh = 10; + /* R/W If set, CVMSEG is available for loads/stores in * kernel/debug mode. */ #if CONFIG_CAVIUM_OCTEON_CVMSEG_SIZE > 0 @@ -375,14 +385,13 @@ void octeon_user_io_init(void) * is max legal value. */ cvmmemctl.s.lmemsz = CONFIG_CAVIUM_OCTEON_CVMSEG_SIZE; + write_c0_cvmmemctl(cvmmemctl.u64); if (smp_processor_id() == 0) pr_notice("CVMSEG size: %d cache lines (%d bytes)\n", CONFIG_CAVIUM_OCTEON_CVMSEG_SIZE, CONFIG_CAVIUM_OCTEON_CVMSEG_SIZE * 128); - write_c0_cvmmemctl(cvmmemctl.u64); - /* Move the performance counter interrupts to IRQ 6 */ cvmctl = read_c0_cvmctl(); cvmctl &= ~(7 << 7); @@ -758,6 +767,31 @@ EXPORT_SYMBOL(prom_putchar); void prom_free_prom_memory(void) { + if (OCTEON_IS_MODEL(OCTEON_CN63XX_PASS1_X)) { + /* Check for presence of Core-14449 fix. */ + u32 insn; + u32 *foo; + + foo = &insn; + + asm volatile("# before" : : : "memory"); + prefetch(foo); + asm volatile( + ".set push\n\t" + ".set noreorder\n\t" + "bal 1f\n\t" + "nop\n" + "1:\tlw %0,-12($31)\n\t" + ".set pop\n\t" + : "=r" (insn) : : "$31", "memory"); + + if ((insn >> 26) != 0x33) + panic("No PREF instruction at Core-14449 probe point.\n"); + + if (((insn >> 16) & 0x1f) != 28) + panic("Core-14449 WAR not in place (%04x).\n" + "Please build kernel with proper options (CONFIG_CAVIUM_CN63XXP1).\n", insn); + } #ifdef CONFIG_CAVIUM_DECODE_RSL cvmx_interrupt_rsl_enable(); diff --git a/arch/mips/mm/uasm.c b/arch/mips/mm/uasm.c index d2647a4e012b..23afdebc8e5c 100644 --- a/arch/mips/mm/uasm.c +++ b/arch/mips/mm/uasm.c @@ -405,7 +405,6 @@ I_u1u2u3(_mfc0) I_u1u2u3(_mtc0) I_u2u1u3(_ori) I_u3u1u2(_or) -I_u2s3u1(_pref) I_0(_rfe) I_u2s3u1(_sc) I_u2s3u1(_scd) @@ -427,6 +426,25 @@ I_u1(_syscall); I_u1u2s3(_bbit0); I_u1u2s3(_bbit1); +#ifdef CONFIG_CPU_CAVIUM_OCTEON +#include +void __uasminit uasm_i_pref(u32 **buf, unsigned int a, signed int b, + unsigned int c) +{ + if (OCTEON_IS_MODEL(OCTEON_CN63XX_PASS1_X) && a <= 24 && a != 5) + /* + * As per erratum Core-14449, replace prefetches 0-4, + * 6-24 with 'pref 28'. + */ + build_insn(buf, insn_pref, c, 28, b); + else + build_insn(buf, insn_pref, c, a, b); +} +UASM_EXPORT_SYMBOL(uasm_i_pref); +#else +I_u2s3u1(_pref) +#endif + /* Handle labels. */ void __uasminit uasm_build_label(struct uasm_label **lab, u32 *addr, int lid) {