David Hendricks ([email protected]) just uploaded a new patch set to 
gerrit, which you can find at http://review.coreboot.org/2729

-gerrit

commit 8df71ac74d177e1e0138a86310a2f5240fa27c25
Author: David Hendricks <[email protected]>
Date:   Thu Mar 14 15:24:57 2013 -0700

    armv7/exynos/snow: set up caches properly
    
    ** do not submit **
    
    This (hopefully) sets up caches more carefully than we were doing
    before. This patch needs a bit more testing before going in.
    
    TODO: Code placement needs to be tidied up. Right now the code is
    scattered about in a less-than-ideal manner due to the differences
    between handling L1 cache (generic for ARMv7) and L2 (SoC-dependent).
    I suspect we'll disable and invalidate L1 in the CPU bootblock, then
    do try to consolidate everything else in a helper function called
    from the board's romstage (since we need board DRAM info for MMU setup).
    
    Change-Id: I7390981190e3213f4e1431f8e56746545c5cc7c9
    Signed-off-by: David Hendricks <[email protected]>
---
 src/arch/armv7/bootblock_simple.c         | 57 +++++++++++++++++++++++++++++++
 src/arch/armv7/include/system.h           | 16 +++++++++
 src/arch/armv7/lib/Makefile.inc           |  1 +
 src/arch/armv7/lib/cache-cp15.c           |  3 +-
 src/arch/armv7/lib/cache_v7.c             |  2 +-
 src/cpu/samsung/exynos5250/Makefile.inc   |  1 -
 src/cpu/samsung/exynos5250/bootblock.c    |  6 ++++
 src/cpu/samsung/exynos5250/exynos_cache.c |  8 ++---
 src/mainboard/google/snow/romstage.c      | 45 ++++++++++++------------
 9 files changed, 105 insertions(+), 34 deletions(-)

diff --git a/src/arch/armv7/bootblock_simple.c 
b/src/arch/armv7/bootblock_simple.c
index 0132b87..0b2d884 100644
--- a/src/arch/armv7/bootblock_simple.c
+++ b/src/arch/armv7/bootblock_simple.c
@@ -24,9 +24,57 @@
 #include <arch/stages.h>
 #include <cbfs.h>
 #include <console/console.h>
+#include <system.h>
 
 #include "stages.c"
 
+/*
+ * Set/clear program flow prediction and return the previous state.
+ */
+static int config_branch_prediction(int set_cr_z)
+{
+       unsigned int cr;
+
+       /* System Control Register: 11th bit Z Branch prediction enable */
+       cr = get_cr();
+       set_cr(set_cr_z ? cr | CR_Z : cr & ~CR_Z);
+
+       return cr & CR_Z;
+}
+
+/* Cache and MMU init */
+static void armv7_invalidate_caches(void)
+{
+       unsigned int cr;
+
+       /*
+        * From Cortex-A Series Programmers guide (Example 15-3):
+        * 1. Disable MMU
+        * 2. Disable L1 caches (example disables i-cache then d-cache)
+        * 3. Invalidate L1 caches (same order)
+        * 4. Invalidate TLB
+        *
+        * L2 cache setup will be done by SoC-specific code. MMU setup
+        * needs to be done after DRAM init in board-specific code.
+        */
+
+       /* Disable MMU */
+       cr = get_cr();
+       cr &= ~CR_M;
+       set_cr(cr);
+
+       /* Disable L1 caches */
+       icache_disable();
+       dcache_disable();
+
+       /* Invalidate caches */
+       invalidate_icache_all();
+       invalidate_dcache_all();
+
+       /* Invalidate TLB */
+       v7_inval_tlb();
+}
+
 static int boot_cpu(void)
 {
        /*
@@ -42,6 +90,15 @@ void main(void)
        const char *stage_name = "fallback/romstage";
        void *entry;
 
+       armv7_invalidate_caches();
+
+       /*
+        * Branch prediction enable.
+        * Note: If booting from USB, we need to disable branch prediction
+        * before copying from USB into RAM (FIXME: why?)
+        */
+       config_branch_prediction(1);
+
        if (boot_cpu()) {
                bootblock_cpu_init();
                bootblock_mainboard_init();
diff --git a/src/arch/armv7/include/system.h b/src/arch/armv7/include/system.h
index 053df8d..9a694ba 100644
--- a/src/arch/armv7/include/system.h
+++ b/src/arch/armv7/include/system.h
@@ -64,6 +64,20 @@ static inline void set_cr(unsigned int val)
        isb();
 }
 
+static inline unsigned int get_acr(void)
+{
+       unsigned int val;
+       asm("mrc p15, 0, %0, c1, c0, 1  @ get ACR" : "=r" (val) : : "cc");
+       return val;
+}
+
+static inline void set_acr(unsigned int val)
+{
+       asm volatile("mcr p15, 0, %0, c1, c0, 1 @ set ACR"
+         : : "r" (val) : "cc");
+       isb();
+}
+
 /* options available for data cache on each page */
 enum dcache_option {
        DCACHE_OFF,
@@ -97,6 +111,8 @@ void mmu_page_table_flush(unsigned long start, unsigned long 
stop);
 
 void mmu_setup(unsigned long start, unsigned long size);
 
+void v7_inval_tlb(void);
+
 void arm_init_before_mmu(void);
 
  /*
diff --git a/src/arch/armv7/lib/Makefile.inc b/src/arch/armv7/lib/Makefile.inc
index 508f776..75e6752 100644
--- a/src/arch/armv7/lib/Makefile.inc
+++ b/src/arch/armv7/lib/Makefile.inc
@@ -14,6 +14,7 @@ ramstage-y += div0.c
 #ramstage-y += memcpy.S
 #ramstage-y += memset.S
 ramstage-y += syslib.c
+ramstage-y += cache-cp15.c
 ramstage-y += cache_v7.c
 
 #FIXME(dhendrix): should this be a config option?
diff --git a/src/arch/armv7/lib/cache-cp15.c b/src/arch/armv7/lib/cache-cp15.c
index e08ea57..32f3c79 100644
--- a/src/arch/armv7/lib/cache-cp15.c
+++ b/src/arch/armv7/lib/cache-cp15.c
@@ -123,8 +123,7 @@ inline void mmu_setup(unsigned long start, unsigned long 
size_mb)
        int i;
        u32 reg;
 
-       arm_init_before_mmu();
-
+//     arm_init_before_mmu();
        /* Set up an identity-mapping for all 4GB, rw for everyone */
        for (i = 0; i < 4096; i++)
                set_section_dcache(i, DCACHE_OFF);
diff --git a/src/arch/armv7/lib/cache_v7.c b/src/arch/armv7/lib/cache_v7.c
index 31072c7..1764351 100644
--- a/src/arch/armv7/lib/cache_v7.c
+++ b/src/arch/armv7/lib/cache_v7.c
@@ -226,7 +226,7 @@ static void v7_dcache_maint_range(u32 start, u32 stop, u32 
range_op)
 }
 
 /* Invalidate TLB */
-static void v7_inval_tlb(void)
+void v7_inval_tlb(void)
 {
        /* Invalidate entire unified TLB */
        asm volatile ("mcr p15, 0, %0, c8, c7, 0" : : "r" (0));
diff --git a/src/cpu/samsung/exynos5250/Makefile.inc 
b/src/cpu/samsung/exynos5250/Makefile.inc
index 2774b12..961b719 100644
--- a/src/cpu/samsung/exynos5250/Makefile.inc
+++ b/src/cpu/samsung/exynos5250/Makefile.inc
@@ -30,7 +30,6 @@ ramstage-y += power.c
 ramstage-y += soc.c
 ramstage-$(CONFIG_CONSOLE_SERIAL_UART) += uart.c
 ramstage-y += cpu.c
-ramstage-y += exynos_cache.c
 
 #ramstage-$(CONFIG_SATA_AHCI) += sata.c
 
diff --git a/src/cpu/samsung/exynos5250/bootblock.c 
b/src/cpu/samsung/exynos5250/bootblock.c
index 949468f..48f390a 100644
--- a/src/cpu/samsung/exynos5250/bootblock.c
+++ b/src/cpu/samsung/exynos5250/bootblock.c
@@ -17,7 +17,13 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include <armv7.h>
+
 void bootblock_cpu_init(void);
 void bootblock_cpu_init(void)
 {
+       /* Enable L2 cache */
+       /* FIXME: maybe do this in romstage along with the other cache
+        * init functions? */
+       v7_outer_cache_enable();
 }
diff --git a/src/cpu/samsung/exynos5250/exynos_cache.c 
b/src/cpu/samsung/exynos5250/exynos_cache.c
index 7f4effe..87eded5 100644
--- a/src/cpu/samsung/exynos5250/exynos_cache.c
+++ b/src/cpu/samsung/exynos5250/exynos_cache.c
@@ -34,15 +34,11 @@ enum l2_cache_params {
 };
 
 
-/* FIXME(dhendrix): maybe move this to a romstage-specific file? */
-#ifdef __PRE_RAM__
 void enable_caches(void)
 {
-       /* Enable D-cache. I-cache is already enabled in start.S */
-       /* can't use it anyway -- it has dependencies we have to fix. */
-       //dcache_enable();
+       icache_enable(CONFIG_SYS_SDRAM_BASE, CONFIG_DRAM_SIZE_MB);
+       dcache_enable(CONFIG_SYS_SDRAM_BASE, CONFIG_DRAM_SIZE_MB);
 }
-#endif
 
 /*
  * Set L2 cache parameters
diff --git a/src/mainboard/google/snow/romstage.c 
b/src/mainboard/google/snow/romstage.c
index ea2feec..3b14d91 100644
--- a/src/mainboard/google/snow/romstage.c
+++ b/src/mainboard/google/snow/romstage.c
@@ -20,6 +20,7 @@
 #include <types.h>
 #include <system.h>
 
+#include <armv7.h>
 #include <cache.h>
 #include <cbfs.h>
 #include <common.h>
@@ -52,20 +53,6 @@ static int board_wakeup_permitted(void)
 }
 #endif
 
-/*
- * Set/clear program flow prediction and return the previous state.
- */
-static int config_branch_prediction(int set_cr_z)
-{
-       unsigned int cr;
-
-       /* System Control Register: 11th bit Z Branch prediction enable */
-       cr = get_cr();
-       set_cr(set_cr_z ? cr | CR_Z : cr & ~CR_Z);
-
-       return cr & CR_Z;
-}
-
 static void initialize_s5p_mshc(void)
 {
        /* MMC0: Fixed, 8 bit mode, connected with GPIO. */
@@ -94,13 +81,16 @@ void main(void)
        struct arm_clk_ratios *arm_ratios;
        int ret;
        void *entry;
-
-       /* FIXME: if we boot from USB, we need to disable branch prediction
-        * before copying from USB into RAM */
-       config_branch_prediction(1);
+       unsigned int cr;
 
        clock_set_rate(PERIPH_ID_SPI1, 50000000); /* set spi clock to 50Mhz */
 
+       /*
+        * FIXME: Do necessary I2C init so low-level PMIC code doesn't need to.
+        * Also, we should only call power_init() on cold boot.
+        */
+       power_init();
+
        /* Clock must be initialized before console_init, otherwise you may need
         * to re-initialize serial console drivers again. */
        mem = get_mem_timings();
@@ -109,12 +99,6 @@ void main(void)
 
        console_init();
 
-       /*
-        * FIXME: Do necessary I2C init so low-level PMIC code doesn't need to.
-        * Also, we should only call power_init() on cold boot.
-        */
-       power_init();
-
        if (!mem) {
                printk(BIOS_CRIT, "Unable to auto-detect memory timings\n");
                while(1);
@@ -132,8 +116,21 @@ void main(void)
                while(1);
        }
 
+       /* Set up MMU and caches */
        mmu_setup(CONFIG_SYS_SDRAM_BASE, CONFIG_DRAM_SIZE_MB);
 
+       /* Enable D-side prefetch */
+       cr = get_acr();
+       cr |= (1 << 2);
+       set_acr(cr);
+       CP15DSB;
+       CP15ISB;
+
+       /* FIXME: these functions take because the "generic" cache_enable()
+        * tries to call mmu_setup if mmu has not already been enabled */
+       icache_enable(CONFIG_SYS_SDRAM_BASE, CONFIG_DRAM_SIZE_MB);
+       dcache_enable(CONFIG_SYS_SDRAM_BASE, CONFIG_DRAM_SIZE_MB);
+
        initialize_s5p_mshc();
 
        graphics();

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