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    Subject[PATCH 03/21] amd64_edac: add memory scrubber interface
    Date
    From: Doug Thompson <dougthompson@xmission.com>

    Signed-off-by: Doug Thompson <dougthompson@xmission.com>
    Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
    ---
    drivers/edac/amd64_edac.c | 116 +++++++++++++++++++++++++++++++++++++++++++++
    1 files changed, 116 insertions(+), 0 deletions(-)

    diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
    index c633bea..13dc472 100644
    --- a/drivers/edac/amd64_edac.c
    +++ b/drivers/edac/amd64_edac.c
    @@ -1001,3 +1001,119 @@ static struct scrubrate {
    #define F10_MIN_SCRUB_RATE_BITS 0x5
    #define F11_MIN_SCRUB_RATE_BITS 0x6

    +/*
    + * Memory scrubber control interface. For the K8, memory scrubbing is handled by
    + * hardware and can involve L2 cache, dcache as well as the main memory. With
    + * F10, this is extended to L3 cache scrubbing on CPU models sporting that
    + * functionality.
    + * This causes the "units" for the scrubbing speed to vary from 64 byte blocks
    + * (dram) over to cache lines. This is nasty, so we will use bandwidth in
    + * bytes/sec for the setting.
    + * Currently, we only do dram scrubbing. If the scrubbing is done in software on
    + * other archs, we might not have access to the caches directly.
    + */
    +
    +/*
    + * amd64_search_set_scrub_rate
    + *
    + * scan the scrub rate mapping table for a close or matching bandwidth value to
    + * issue. If requested is too big, then use last maximum value found.
    + */
    +static int amd64_search_set_scrub_rate(struct pci_dev *ctl, u32 new_bw,
    + u32 min_scrubrate)
    +{
    + u32 scrubval;
    + int i;
    +
    + /*
    + * map the configured rate (new_bw) to a value specific to the AMD64
    + * memory controller and apply to register. Search for the first
    + * bandwidth entry that is greater or equal than the setting requested
    + * and program that. If at last entry, accept that as the maximum. This
    + * saves the user from determing the maximum empirically.
    + */
    + for (i = 0; i < ARRAY_SIZE(scrubrates); i++) {
    + /*
    + * skip scrub rates which aren't recommended
    + * (see F10 BKDG, F3x58)
    + */
    + if (scrubrates[i].scrubval < min_scrubrate)
    + continue;
    +
    + if (scrubrates[i].bandwidth <= new_bw)
    + break;
    +
    + /*
    + * if no suitable bandwidth found, turn off DRAM scrubbing
    + * entirely by falling back to the last element in the
    + * scrubrates array.
    + */
    + }
    +
    + scrubval = scrubrates[i].scrubval;
    + if (scrubval)
    + edac_printk(KERN_DEBUG, EDAC_MC,
    + "Setting scrub rate bandwidth: %u\n",
    + scrubrates[i].bandwidth);
    + else
    + edac_printk(KERN_DEBUG, EDAC_MC,
    + "Turning scrubbing off.\n");
    +
    + pci_write_bits32(ctl, K8_SCRCTRL, scrubval, 0x001F);
    +
    + return 0;
    +}
    +
    +static int amd64_set_scrub_rate(struct mem_ctl_info *mci, u32 *bandwidth)
    +{
    + struct amd64_pvt *pvt = mci->pvt_info;
    + u32 min_scrubrate = 0x0;
    +
    + switch (boot_cpu_data.x86) {
    + case 0xf:
    + min_scrubrate = K8_MIN_SCRUB_RATE_BITS;
    + break;
    + case 0x10:
    + min_scrubrate = F10_MIN_SCRUB_RATE_BITS;
    + break;
    + case 0x11:
    + min_scrubrate = F11_MIN_SCRUB_RATE_BITS;
    + break;
    +
    + default:
    + amd64_printk(KERN_ERR, "Unsupported family!\n");
    + break;
    + }
    + return amd64_search_set_scrub_rate(pvt->misc_f3_ctl, *bandwidth,
    + min_scrubrate);
    +}
    +
    +static int amd64_get_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
    +{
    + struct amd64_pvt *pvt = mci->pvt_info;
    + u32 scrubval = 0;
    + int status = -1;
    + int i;
    + int err;
    +
    + err = pci_read_config_dword(pvt->misc_f3_ctl, K8_SCRCTRL, &scrubval);
    + if (err != 0)
    + debugf0("%s() Reading K8_SCRCTRL failed\n", __func__);
    +
    + scrubval = scrubval & 0x001F;
    +
    + edac_printk(KERN_DEBUG, EDAC_MC,
    + "pci-read, sdram scrub control value: %d \n", scrubval);
    +
    + for (i = 0; ARRAY_SIZE(scrubrates); i++) {
    + if (scrubrates[i].scrubval == scrubval) {
    + *bw = scrubrates[i].bandwidth;
    + status = 0;
    + break;
    + }
    + }
    +
    + return status;
    +}
    +
    +
    --
    1.6.2.4



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