From: Tien Fong Chee tien.fong.chee@intel.com
The SDRAM must first be rewritten by zeroes if ECC is used to initialize the ECC metadata. Make the CPU overwrite the DRAM with zeroes in such a case. This scrubbing implementation turns the caches on temporarily, then overwrites the whole RAM with zeroes, flushes the caches and turns them off again. This provides satisfactory performance.
Signed-off-by: Tien Fong Chee tien.fong.chee@intel.com --- drivers/ddr/altera/sdram_s10.c | 44 ++++++++++++++++++++++++++++++++++++++++ 1 files changed, 44 insertions(+), 0 deletions(-)
diff --git a/drivers/ddr/altera/sdram_s10.c b/drivers/ddr/altera/sdram_s10.c index 48f4f47..cce261f 100644 --- a/drivers/ddr/altera/sdram_s10.c +++ b/drivers/ddr/altera/sdram_s10.c @@ -8,6 +8,7 @@ #include <errno.h> #include <div64.h> #include <asm/io.h> +#include <linux/sizes.h> #include <wait_bit.h> #include <asm/arch/firewall_s10.h> #include <asm/arch/sdram_s10.h> @@ -134,6 +135,47 @@ static int poll_hmc_clock_status(void) SYSMGR_HMC_CLK_STATUS_MSK, true, 1000, false); }
+/* Initialize SDRAM ECC bits to avoid false DBE */ +static void sdram_init_ecc_bits(unsigned long long size) +{ + /* 1GB per chunk */ + unsigned long long size_byte = SZ_1G; + unsigned long long remaining_size; + unsigned long long dst_addr = 0x8000; + unsigned int start = get_timer(0); + + icache_enable(); + + memset(0, 0, dst_addr); + gd->arch.tlb_addr = 0x4000; + gd->arch.tlb_size = PGTABLE_SIZE; + + dcache_enable(); + + remaining_size = size - dst_addr; + printf("DDRCAL: Scrubbing ECC RAM (%d MiB).\n", (u32)(size >> 20)); + + while (remaining_size) { + if (remaining_size <= size_byte) { + memset((void *)dst_addr, 0, remaining_size); + break; + } else { + memset((void *)dst_addr, 0, size_byte); + dst_addr += size_byte; + } + + WATCHDOG_RESET(); + remaining_size -= size_byte; + } + + flush_dcache_all(); + printf("DDRCAL: Scrubbing ECC RAM done.\n"); + dcache_disable(); + + printf("SDRAM-ECC: Initialized success with %d ms\n", + (unsigned)get_timer(start)); +} + /** * sdram_mmr_init_full() - Function to initialize SDRAM MMR * @@ -351,6 +393,8 @@ int sdram_mmr_init_full(unsigned int unused) setbits_le32(SOCFPGA_SDR_ADDRESS + ECCCTRL2, (DDR_HMC_ECCCTL2_RMW_EN_SET_MSK | DDR_HMC_ECCCTL2_AWB_EN_SET_MSK)); + + sdram_init_ecc_bits(gd->ram_size); } else { clrbits_le32(SOCFPGA_SDR_ADDRESS + ECCCTRL1, (DDR_HMC_ECCCTL_AWB_CNT_RST_SET_MSK |