Re: [PATCH v3] edac: Handle EDAC ECC errors for Family 16h

From: Aravind
Date: Tue Apr 16 2013 - 13:15:55 EST


On 04/16/2013 09:24 AM, Borislav Petkov wrote:
On Mon, Apr 15, 2013 at 01:56:00PM -0500, Aravind Gopalakrishnan wrote:
Add code to handle ECC decoding for fam16h. Support exists for
previous families already, so code has been reused werever applicable
and some code has been added to handle fam16h specific operations.

The patch was tested on Fam16h with ECC turned on
using the mce_amd_inj facility and works fine.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
---
arch/x86/kernel/amd_nb.c | 4 +-
drivers/edac/amd64_edac.c | 96 +++++++++++++++++++++++++++++++++++++++++++--
drivers/edac/amd64_edac.h | 4 +-
include/linux/pci_ids.h | 2 +
4 files changed, 101 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
index 4c39baa..a8bbcf6 100644
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -16,12 +16,14 @@ const struct pci_device_id amd_nb_misc_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_10H_NB_MISC) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3) },
This chunk doesn't apply even on current Linus. For the future,
if you're sending x86 patches, always create them against current
tip/master which contains the latest x86 patch queue.

This one case in point, please redo it against tip/master.

I had based off bp.git's master... and it misses an additional 'PCI_DEVICE' line (Hence the conflict)
I shall redo it against Linus's tree..
{}
};
EXPORT_SYMBOL(amd_nb_misc_ids);
static struct pci_device_id amd_nb_link_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F4) },
{}
};
@@ -77,7 +79,7 @@ int amd_cache_northbridges(void)
next_northbridge(link, amd_nb_link_ids);
}
- /* some CPU families (e.g. family 0x11) do not support GART */
+ /* some CPU families (e.g. family 0x11, 0x16) do not support GART */
if (boot_cpu_data.x86 == 0xf || boot_cpu_data.x86 == 0x10 ||
boot_cpu_data.x86 == 0x15)
amd_northbridges.flags |= AMD_NB_GART;
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 9a8bebc..9173173 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -98,6 +98,7 @@ int __amd64_write_pci_cfg_dword(struct pci_dev *pdev, int offset,
*
* F15h: we select which DCT we access using F1x10C[DctCfgSel]
*
+ * F16h has only 1 DCT
*/
static int k8_read_dct_pci_cfg(struct amd64_pvt *pvt, int addr, u32 *val,
const char *func)
@@ -133,6 +134,15 @@ static int f15_read_dct_pci_cfg(struct amd64_pvt *pvt, int addr, u32 *val,
return __amd64_read_pci_cfg_dword(pvt->F2, addr, val, func);
}
+static int f16_read_dct_pci_cfg(struct amd64_pvt *pvt, int addr, u32 *val,
+ const char *func)
+{
+ if (addr >= 0x100)
+ return -EINVAL;
I'm very sceptical F16h doesn't have F2 extended PCI config addresses.
Please check the BKDG.

If it does have, use f10_read_dct_pci_cfg, if it doesn't, use
k8_read_dct_pci_cfg without introducing a new accessor while the other
ones can be used.

Whichever one you take, please add a comment somewhere explaining why it
is ok to use it on F16h.

Here, What I really wanted to do was to restrict the access to only 1 DCT (as fam16 does not have a DCT1 and hence not allow any addr > =0x100). Yes, for this I can modify the code to just use f10_read_dct_pci_cfg or k8_read_dct_pci_cfg.
However, looking up BKDG once again, I see that the DCT config select register is similar to fam15's except there are extended bits for D18F2x10C[DctCfgSel].
While there was one bit (bit 0) for fam15, it is 3 bits (bits 2:0) for fam16.
There is only 1 DCT in F16h, hence only the value '000b' is accepted while '111b to 0001b' are reserved. Due to this, there is another way to handle this in the code:
* Have a seperate accesor for fam16h which does this:

static void f15h_select_dct(struct amd64_pvt *pvt, u8 dct)
{
u32 reg = 0;

amd64_read_pci_cfg(pvt->F1, DCT_CFG_SEL, &reg);
reg &= 0xfffffff8;
reg |= dct;
amd64_write_pci_cfg(pvt->F1, DCT_CFG_SEL, reg);
}

static int f16_read_dct_pci_cfg(struct amd64_pvt *pvt, int addr, u32 *val,
const char *func)
{
u32 reg = 0;
u8 dct = 0;

if (addr >= 0x100) {
return -EINVAL;
}

f15_select_dct(pvt, 0);

return __amd64_read_pci_cfg_dword(pvt->F2, addr, val, func);
}

1. Generalise f15h_select_dct function by doing 'reg &= 0xfffffff8'
2. Call this with 'dct' value of 0

Do let me know what might be the preferred method..

+ return __amd64_read_pci_cfg_dword(pvt->F2, addr, val, func);
+}
+
/*
* Memory scrubber control interface. For K8, memory scrubbing is handled by
* hardware and can involve L2 cache, dcache as well as the main memory. With
@@ -326,7 +336,42 @@ static void get_cs_base_and_mask(struct amd64_pvt *pvt, int csrow, u8 dct,
base_bits = GENMASK(21, 31) | GENMASK(9, 15);
mask_bits = GENMASK(21, 29) | GENMASK(9, 15);
addr_shift = 4;
- } else {
+ }
+
+ /*
+ * there are two addr_shift values for F16h.
+ * addr_shift of 8 for high bits and addr_shift of 6
+ * for low bits. So handle it differently.
+ */
+ else if (boot_cpu_data.x86 == 0x16) {
+ /* variables specific to F16h */
Well, no need for that comment - we know what local variables are.

+ u64 base_bits_low, base_bits_high;
+ u64 mask_bits_low, mask_bits_high;
+ u8 addr_shift_low, addr_shift_high;
+
+ csbase = pvt->csels[dct].csbases[csrow];
+ csmask = pvt->csels[dct].csmasks[csrow >> 1];
+ base_bits_low = mask_bits_low = GENMASK(5 , 15);
+ base_bits_high = mask_bits_high = GENMASK(19 , 30);
+ addr_shift_low = 6;
+ addr_shift_high = 8;
Hold on, are you saying "D18F2x[5C:40]_dct[1:0] DRAM CS Base Address"
register definitions in the F16h BKDG has this:

30:19 -> BaseAddr[38:27]: normalized physical base address bits [38:27]

and

15:5 -> BaseAddr[21:11]: normalized physical base address bits [21:11]

?

Please verify with BKDG authors whether those numbers are correct
because the diff of 8 address bits has always been this up until now.

That is correct. (I have verified it internally too..)

+ *base = (((csbase & base_bits_high)
+ << addr_shift_high) |
+ ((csbase & base_bits_low)
+ << addr_shift_low));
+ *mask = ~0ULL;
+ *mask &= ~((mask_bits_high
+ << addr_shift_high) |
+ (mask_bits_low
+ << addr_shift_low));
+ *mask |= (((csmask & mask_bits_high)
+ << addr_shift_high) |
+ ((csmask & mask_bits_low)
+ << addr_shift_low));
+ return;
+ }
+
+ else {
csbase = pvt->csels[dct].csbases[csrow];
csmask = pvt->csels[dct].csmasks[csrow >> 1];
addr_shift = 8;
@@ -1224,6 +1269,23 @@ static int f15_dbam_to_chip_select(struct amd64_pvt *pvt, u8 dct,
return ddr3_cs_size(cs_mode, false);
}
+/*
+ * F16h supports 64 bit DCT interfaces
+ * and has only limited cs_modes
+ */
+static int f16_dbam_to_chip_select(struct amd64_pvt *pvt, u8 dct,
+ unsigned cs_mode)
+{
+ WARN_ON(cs_mode > 12);
+
+ if (cs_mode == 0 || cs_mode == 3 || cs_mode == 4
Those are already caught by ddr3_cs_size().

+ || cs_mode == 6 || cs_mode == 8 || cs_mode == 9
+ || cs_mode == 12)
... which simplifies this check a bit.

Yes, I will make the necessary changes here..

+ return -1;
+ else
+ return ddr3_cs_size(cs_mode, false);
+}
+
static void read_dram_ctl_register(struct amd64_pvt *pvt)
{
@@ -1681,6 +1743,17 @@ static struct amd64_family_type amd64_family_types[] = {
.read_dct_pci_cfg = f15_read_dct_pci_cfg,
}
},
+ [F16_CPUS] = {
+ .ctl_name = "F16h",
+ .f1_id = PCI_DEVICE_ID_AMD_16H_NB_F1,
+ .f3_id = PCI_DEVICE_ID_AMD_16H_NB_F3,
+ .ops = {
+ .early_channel_count = f1x_early_channel_count,
+ .map_sysaddr_to_csrow = f1x_map_sysaddr_to_csrow,
+ .dbam_to_cs = f16_dbam_to_chip_select,
+ .read_dct_pci_cfg = f16_read_dct_pci_cfg,
+ }
+ },
};
static struct pci_dev *pci_get_related_function(unsigned int vendor,
@@ -2071,8 +2144,12 @@ static void read_mc_regs(struct amd64_pvt *pvt)
pvt->ecc_sym_sz = 4;
if (c->x86 >= 0x10) {
- amd64_read_pci_cfg(pvt->F3, EXT_NB_MCA_CFG, &tmp);
- amd64_read_dct_pci_cfg(pvt, DBAM1, &pvt->dbam1);
+
+ /* F16h has only one DCT, hence cannot read DCT1 reg. */
+ if (c->x86 != 0x16) {
+ amd64_read_pci_cfg(pvt->F3, EXT_NB_MCA_CFG, &tmp);
+ amd64_read_dct_pci_cfg(pvt, DBAM1, &pvt->dbam1);
+ }
/* F10h, revD and later can do x8 ECC too */
if ((c->x86 > 0x10 || c->x86_model > 7) && tmp & BIT(25))
pvt->ecc_sym_sz = 8;
This won't work on F16h because this last check above relies on tmp but
with your change above, tmp will be uninitialized.

If F16h supports x8 ECC too, you need to take the detection of
->ecc_sym_sz out of this family ">= 0x10" check.

You are right again! I shall fix this up too..

Thanks.



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