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    Subject[PATCH 09/22] amd64_edac: add functionality to compute the DRAM hole
    Date
    From: Doug Thompson <dougthompson@xmission.com>

    Borislav:

    - cleanup/fix comments, add BKDG refs
    - cleanup debug calls

    Reviewed-by: Mauro Carvalho Chehab <mchehab@redhat.com>
    Signed-off-by: Doug Thompson <dougthompson@xmission.com>
    Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
    ---
    drivers/edac/amd64_edac.c | 166 +++++++++++++++++++++++++++++++++++++++++++++
    1 files changed, 166 insertions(+), 0 deletions(-)

    diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
    index a774f34..4716fb5 100644
    --- a/drivers/edac/amd64_edac.c
    +++ b/drivers/edac/amd64_edac.c
    @@ -269,3 +269,169 @@ err_no_match:

    return NULL;
    }
    +
    +/*
    + * Extract the DRAM CS base address from selected csrow register.
    + */
    +static u64 base_from_dct_base(struct amd64_pvt *pvt, int csrow)
    +{
    + return ((u64) (amd64_get_dct_base(pvt, 0, csrow) & pvt->dcsb_base)) <<
    + pvt->dcs_shift;
    +}
    +
    +/*
    + * Extract the mask from the dcsb0[csrow] entry in a CPU revision-specific way.
    + */
    +static u64 mask_from_dct_mask(struct amd64_pvt *pvt, int csrow)
    +{
    + u64 dcsm_bits, other_bits;
    + u64 mask;
    +
    + /* Extract bits from DRAM CS Mask. */
    + dcsm_bits = amd64_get_dct_mask(pvt, 0, csrow) & pvt->dcsm_mask;
    +
    + other_bits = pvt->dcsm_mask;
    + other_bits = ~(other_bits << pvt->dcs_shift);
    +
    + /*
    + * The extracted bits from DCSM belong in the spaces represented by
    + * the cleared bits in other_bits.
    + */
    + mask = (dcsm_bits << pvt->dcs_shift) | other_bits;
    +
    + return mask;
    +}
    +
    +/*
    + * @input_addr is an InputAddr associated with the node given by mci. Return the
    + * csrow that input_addr maps to, or -1 on failure (no csrow claims input_addr).
    + */
    +static int input_addr_to_csrow(struct mem_ctl_info *mci, u64 input_addr)
    +{
    + struct amd64_pvt *pvt;
    + int csrow;
    + u64 base, mask;
    +
    + pvt = mci->pvt_info;
    +
    + /*
    + * Here we use the DRAM CS Base and DRAM CS Mask registers. For each CS
    + * base/mask register pair, test the condition shown near the start of
    + * section 3.5.4 (p. 84, BKDG #26094, K8, revA-E).
    + */
    + for (csrow = 0; csrow < CHIPSELECT_COUNT; csrow++) {
    +
    + /* This DRAM chip select is disabled on this node */
    + if ((pvt->dcsb0[csrow] & K8_DCSB_CS_ENABLE) == 0)
    + continue;
    +
    + base = base_from_dct_base(pvt, csrow);
    + mask = ~mask_from_dct_mask(pvt, csrow);
    +
    + if ((input_addr & mask) == (base & mask)) {
    + debugf2("InputAddr 0x%lx matches csrow %d (node %d)\n",
    + (unsigned long)input_addr, csrow,
    + pvt->mc_node_id);
    +
    + return csrow;
    + }
    + }
    +
    + debugf2("no matching csrow for InputAddr 0x%lx (MC node %d)\n",
    + (unsigned long)input_addr, pvt->mc_node_id);
    +
    + return -1;
    +}
    +
    +/*
    + * Return the base value defined by the DRAM Base register for the node
    + * represented by mci. This function returns the full 40-bit value despite the
    + * fact that the register only stores bits 39-24 of the value. See section
    + * 3.4.4.1 (BKDG #26094, K8, revA-E)
    + */
    +static inline u64 get_dram_base(struct mem_ctl_info *mci)
    +{
    + struct amd64_pvt *pvt = mci->pvt_info;
    +
    + return pvt->dram_base[pvt->mc_node_id];
    +}
    +
    +/*
    + * Obtain info from the DRAM Hole Address Register (section 3.4.8, pub #26094)
    + * for the node represented by mci. Info is passed back in *hole_base,
    + * *hole_offset, and *hole_size. Function returns 0 if info is valid or 1 if
    + * info is invalid. Info may be invalid for either of the following reasons:
    + *
    + * - The revision of the node is not E or greater. In this case, the DRAM Hole
    + * Address Register does not exist.
    + *
    + * - The DramHoleValid bit is cleared in the DRAM Hole Address Register,
    + * indicating that its contents are not valid.
    + *
    + * The values passed back in *hole_base, *hole_offset, and *hole_size are
    + * complete 32-bit values despite the fact that the bitfields in the DHAR
    + * only represent bits 31-24 of the base and offset values.
    + */
    +int amd64_get_dram_hole_info(struct mem_ctl_info *mci, u64 *hole_base,
    + u64 *hole_offset, u64 *hole_size)
    +{
    + struct amd64_pvt *pvt = mci->pvt_info;
    + u64 base;
    +
    + /* only revE and later have the DRAM Hole Address Register */
    + if (boot_cpu_data.x86 == 0xf && pvt->ext_model < OPTERON_CPU_REV_E) {
    + debugf1(" revision %d for node %d does not support DHAR\n",
    + pvt->ext_model, pvt->mc_node_id);
    + return 1;
    + }
    +
    + /* only valid for Fam10h */
    + if (boot_cpu_data.x86 == 0x10 &&
    + (pvt->dhar & F10_DRAM_MEM_HOIST_VALID) == 0) {
    + debugf1(" Dram Memory Hoisting is DISABLED on this system\n");
    + return 1;
    + }
    +
    + if ((pvt->dhar & DHAR_VALID) == 0) {
    + debugf1(" Dram Memory Hoisting is DISABLED on this node %d\n",
    + pvt->mc_node_id);
    + return 1;
    + }
    +
    + /* This node has Memory Hoisting */
    +
    + /* +------------------+--------------------+--------------------+-----
    + * | memory | DRAM hole | relocated |
    + * | [0, (x - 1)] | [x, 0xffffffff] | addresses from |
    + * | | | DRAM hole |
    + * | | | [0x100000000, |
    + * | | | (0x100000000+ |
    + * | | | (0xffffffff-x))] |
    + * +------------------+--------------------+--------------------+-----
    + *
    + * Above is a diagram of physical memory showing the DRAM hole and the
    + * relocated addresses from the DRAM hole. As shown, the DRAM hole
    + * starts at address x (the base address) and extends through address
    + * 0xffffffff. The DRAM Hole Address Register (DHAR) relocates the
    + * addresses in the hole so that they start at 0x100000000.
    + */
    +
    + base = dhar_base(pvt->dhar);
    +
    + *hole_base = base;
    + *hole_size = (0x1ull << 32) - base;
    +
    + if (boot_cpu_data.x86 > 0xf)
    + *hole_offset = f10_dhar_offset(pvt->dhar);
    + else
    + *hole_offset = k8_dhar_offset(pvt->dhar);
    +
    + debugf1(" DHAR info for node %d base 0x%lx offset 0x%lx size 0x%lx\n",
    + pvt->mc_node_id, (unsigned long)*hole_base,
    + (unsigned long)*hole_offset, (unsigned long)*hole_size);
    +
    + return 0;
    +}
    +EXPORT_SYMBOL_GPL(amd64_get_dram_hole_info);
    +
    +
    --
    1.6.2.4



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