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

-gerrit

commit f310fd07028a0f6011dd3834786eab74a80409ca
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:
    - Clean up. Most of this is now done in a generic manner in
    bootblock_simple, so a lot of earlier code can go away.
    - Set cache policy and enable caches.
    - Replace imported cache routines with BSD-licensed version?
    
    Change-Id: I7390981190e3213f4e1431f8e56746545c5cc7c9
    Signed-off-by: David Hendricks <[email protected]>
---
 src/arch/armv7/bootblock_simple.c         | 245 ++++++++++++++++++++++++++++++
 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    |  30 ++++
 src/cpu/samsung/exynos5250/exynos_cache.c |   8 +-
 src/mainboard/google/snow/ramstage.c      |  15 --
 src/mainboard/google/snow/romstage.c      |  45 +++---
 10 files changed, 317 insertions(+), 49 deletions(-)

diff --git a/src/arch/armv7/bootblock_simple.c 
b/src/arch/armv7/bootblock_simple.c
index 0132b87..364209f 100644
--- a/src/arch/armv7/bootblock_simple.c
+++ b/src/arch/armv7/bootblock_simple.c
@@ -24,9 +24,245 @@
 #include <arch/stages.h>
 #include <cbfs.h>
 #include <console/console.h>
+#include <lib.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;
+}
+
+#if 0
+/* 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();
+}
+#endif
+
+static inline uint32_t read_clidr(void)
+{
+       uint32_t val = 0;
+       asm volatile ("mrc p15, 1, %0, c0, c0, 1" : "=r" (val));
+       return val;
+}
+
+static inline uint32_t read_ccsidr(void)
+{
+       uint32_t val = 0;
+       asm volatile ("mrc p15, 1, %0, c0, c0, 0" : "=r" (val));
+       return val;
+}
+
+static inline uint32_t read_csselr(void)
+{
+       uint32_t val = 0;
+       asm volatile ("mrc p15, 2, %0, c0, c0, 0" : "=r" (val));
+       return val;
+}
+
+/* Write to Cache Size Selection Register (CSSELR) */
+static inline void write_csselr(uint32_t val)
+{
+       /*
+        * Bits [3:1] - Cache level + 1 (0b000 = L1, 0b110 = L7, 0b111 is rsvd)
+        * Bit 0 - 0 = data or unified cache, 1 = instruction cache
+        */
+       asm volatile ("mcr p15, 2, %0, c0, c0, 0" : : "r" (val));
+       /* Note: Do an ISB if doing CCSIDR after this */
+}
+
+/* Instruction cache invalidate all by PoU */
+static inline void iciallu(void)
+{
+       asm volatile ("mcr p15, 0, %0, c7, c5, 0" : : "r" (0));
+}
+
+/* Data cache invalidate all by set/way */
+static inline void dcisw(uint32_t val)
+{
+       asm volatile ("mcr p15, 0, %0, c7, c6, 0" : : "r" (val));
+}
+
+static void clear_icache(unsigned int level)
+{
+       uint32_t ccselr;
+
+       ccselr = (level << 1) | 1;
+       write_csselr(&ccselr);
+
+       /* icache can be entirely invalidated with one operation.
+        * Note: If branch predictors are architecturally-visible, ICIALLU
+        * also performs a BPIALL operation (B2-1283 in arch manual)
+        */
+       iciallu();
+       isb();
+}
+
+#ifndef __mask
+# define __mask(high, low) ((1UL << (high)) + \
+                            (((1UL << (high)) - 1) - ((1UL << (low)) - 1)))
+#endif
+
+static void clear_dcache(unsigned int level)
+{
+       uint32_t ccsidr, ccselr;
+       unsigned int associativity, num_sets, linesize;
+       unsigned int set, way;
+
+       ccselr = level << 1;
+       write_csselr(&ccselr);
+       isb();  /* ISB to sync the change to the CCSIDR */
+
+       /*
+        * dcache must be invalidated by set/way for portability since virtual
+        * memory mapping is SoC-defined. The number of sets and associativity
+        * is given by CCSIDR. We'll use DCISW to invalidate the dcache.
+        */
+       read_ccsidr(&ccsidr);
+       /* FIXME: Round to the nearest power-of-2 (if necessary) */
+       num_sets = ((ccsidr & __mask(27, 13)) >> 13) + 1;
+       associativity = ((ccsidr & __mask(12, 3)) >> 3) + 1;
+       linesize = 2 << ((ccsidr & 0x7) + 2);
+
+       /*
+        * Set/way operations require an interesting bit packing. See section
+        * B4-35 in the ARMv7 Architecture Reference Manual:
+        *
+        * A: Log2(associativity)
+        * B: L+S
+        * L: Log2(linesize)
+        * S: Log2(num_sets)
+        *
+        * The bits are packed as follows:
+        * 31  31-A          B-1      L-1     4 3 2 1 0
+        * |---|-------------|--------|-------|-|-|-|-|
+        * |Way|    zeros    |   Set  | zeros |level|0|
+        * |---|-------------|--------|-------|-|-|-|-|
+        */
+       for (way = 0; way < assoc; way++) {
+               for (set = 0; set < num_sets; set++) {
+                       uint32_t val = 0;
+                       val |= way << (32 - log2(associativity));
+                       val |= set << log2(linesize);
+                       val |= level << 1;
+                       dcisw(val);
+               }
+       }
+
+}
+
+static void armv7_disable_and_flush_caches(void)
+{
+       uint32_t sctlr, clidr, ccsidr;
+       unsigned int associatvity, num_sets;
+       int level;
+
+       /*
+        * 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.
+        */
+
+       /* Globally disable MMU, caches, and branch prediction (these should
+        * be disabled by default on reset) */
+       sctlr = get_cr();
+       sctlr &= ~(CR_M | CR_C | CR_Z | CR_I);
+       set_cr(sctlr);
+
+       /* Invalidate branch predictor */
+       /* bpiall(); */
+
+       /*
+        * Iterate thru each eache identified in CLIDR and invalidate.
+        */
+       clidr = get_clidr();
+       for (level = 0; level < 7; level++) {
+               unsigned int ctype = (clidr >> (level * 3)) & 0x7;
+               switch(ctype) {
+               case 0x0:
+                       /* no cache */
+                       break;
+               case 0x1:
+                       /* icache only */
+                       clear_icache(level);
+                       break;
+               case 0x2:
+                       /* dcache only */
+                       clear_dcache(level);
+                       break;
+               case 0x3:
+                       /* separate icache and dcache */
+                       clear_icache(level);
+                       clear_dcache(level);
+                       break;
+               case 0x4:
+                       /* unified cache (FIXME: same as dcache only?) */
+                       clear_dcache(level);
+               default:
+                       /* reserved */
+                       break;
+               }
+       }
+
+#if 0
+       /* Disable L1 caches */
+       icache_disable();
+       dcache_disable();
+
+       /* Invalidate caches */
+       invalidate_icache_all();
+       invalidate_dcache_all();
+#endif
+
+       /* Invalidate TLB */
+//     v7_inval_tlb();
+       /* dtlbiall(); */
+}
+
 static int boot_cpu(void)
 {
        /*
@@ -42,6 +278,15 @@ void main(void)
        const char *stage_name = "fallback/romstage";
        void *entry;
 
+       armv7_invalidate_caches();
+
+       /*
+        * Branch prediction enable happens after cache invalidation. (doesn't 
need to?)
+        * 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..74817f4 100644
--- a/src/cpu/samsung/exynos5250/bootblock.c
+++ b/src/cpu/samsung/exynos5250/bootblock.c
@@ -17,7 +17,37 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include <armv7.h>
+
+/*
+ * cortex_a15_cache_init - Initialize caches for Cortex-A15
+ * L1 cache features:
+ * - 32KB 2-way set associative icache, fixed 64-byte line length.
+ * - 32KB 2-way set associative dcache, fixed 64-byte line length.
+ *
+ * L2 cache features:
+ * - Unified, 16-way set associative, fixed 64-byte line length
+ * - Configurable for 512KB, 1M, 2M, or 4MB sizes (SoC-dependent)
+ *
+ * FIXME: move this elsewhere 
+ */
+static void cortex_a15_cache_init(uint32_t dram_start, uint32_t dram_size)
+{
+       /* Disable caches */
+       /* Clean and invalidate caches */
+       /* Set L1 cache parameters */
+       /* Enable L1 cache */
+       /* Set L2 cache parameters */
+       /* Enable L2 cache */
+}
+
 void bootblock_cpu_init(void);
 void bootblock_cpu_init(void)
 {
+       cortex_a15_cache_init();
+
+       /* 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/ramstage.c 
b/src/mainboard/google/snow/ramstage.c
index e4d53cf..687f9b1 100644
--- a/src/mainboard/google/snow/ramstage.c
+++ b/src/mainboard/google/snow/ramstage.c
@@ -23,22 +23,10 @@
 #include <cpu/samsung/exynos5250/clk.h>
 #include <cpu/samsung/exynos5250/power.h>
 
-#include <system.h>    /* FIXME: for testing cache */
-static void cp_delay(void)
-{
-       volatile int i;
-
-       /* copro seems to need some delay between reading and writing */
-       for (i = 0; i < 100; i++)
-               nop();
-       asm volatile("" : : : "memory");
-}
-
 static inline uint32_t read_clidr(void)
 {
        uint32_t val = 0;
        asm volatile ("mrc p15, 1, %0, c0, c0, 1" : "=r" (val));
-       isb();
        return val;
 }
 
@@ -46,7 +34,6 @@ static inline uint32_t read_ccsidr(void)
 {
        uint32_t val = 0;
        asm volatile ("mrc p15, 1, %0, c0, c0, 0" : "=r" (val));
-       isb();
        return val;
 }
 
@@ -54,7 +41,6 @@ static inline uint32_t read_csselr(void)
 {
        uint32_t val = 0;
        asm volatile ("mrc p15, 2, %0, c0, c0, 0" : "=r" (val));
-       isb();
        return val;
 }
 
@@ -66,7 +52,6 @@ static inline void write_csselr(uint32_t val)
         * Bit 0 - 0 = data or unified cache, 1 = instruction cache
         */
        asm volatile ("mcr p15, 2, %0, c0, c0, 0" : : "r" (val));
-       isb();
 }
 
 #ifndef __mask
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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