[U-Boot] [PATCH] ddr: altera: Add ECC DRAM scrubbing support for Stratix 10

[Chee, Tien Fong]

On Mon, 2018-07-23 at 11:46 +0200, Marek Vasut wrote:
> On 07/23/2018 10:20 AM, tien.fong.chee at intel.com wrote:
> > 
> > From: Tien Fong Chee <tien.fong.chee at 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 at 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;
> Are you sure this is valid on arm64 ? It looks like something copies
> from arria10.
The cache on/off is copied from your implementation on Arria 10. Yes, i
have tested it, it is working on Stratix 10 board.
> 
> > 
> > +	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;
> > +	}
> How long does this take ?
1359ms for 2GB. But I have no idea why Arria 10 board can't achieve the
same result. Could you try again on your Arria 10 ES board?
> 
> > 
> > +	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 |
> > 
>