[PATCH 08/22] amd64_edac: add sys addr to memory controller mapping helpers

[Borislav Petkov <borislav.petkov@amd.com>]

From: Doug Thompson <dougthompson@xmission.com>

Borislav:

- cleanup comments
- cleanup debug calls
- simplify find_mc_by_sys_addr's exit path

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 |  141 +++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 141 insertions(+), 0 deletions(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 6876d43..a774f34 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -128,3 +128,144 @@ static int amd64_get_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
 	return status;
 }
 
+/* Map from a CSROW entry to the mask entry that operates on it */
+static inline u32 amd64_map_to_dcs_mask(struct amd64_pvt *pvt, int csrow)
+{
+	return csrow >> (pvt->num_dcsm >> 3);
+}
+
+/* return the 'base' address the i'th CS entry of the 'dct' DRAM controller */
+static u32 amd64_get_dct_base(struct amd64_pvt *pvt, int dct, int csrow)
+{
+	if (dct == 0)
+		return pvt->dcsb0[csrow];
+	else
+		return pvt->dcsb1[csrow];
+}
+
+/*
+ * Return the 'mask' address the i'th CS entry. This function is needed because
+ * there number of DCSM registers on Rev E and prior vs Rev F and later is
+ * different.
+ */
+static u32 amd64_get_dct_mask(struct amd64_pvt *pvt, int dct, int csrow)
+{
+	if (dct == 0)
+		return pvt->dcsm0[amd64_map_to_dcs_mask(pvt, csrow)];
+	else
+		return pvt->dcsm1[amd64_map_to_dcs_mask(pvt, csrow)];
+}
+
+
+/*
+ * In *base and *limit, pass back the full 40-bit base and limit physical
+ * addresses for the node given by node_id.  This information is obtained from
+ * DRAM Base (section 3.4.4.1) and DRAM Limit (section 3.4.4.2) registers. The
+ * base and limit addresses are of type SysAddr, as defined at the start of
+ * section 3.4.4 (p. 70).  They are the lowest and highest physical addresses
+ * in the address range they represent.
+ */
+static void amd64_get_base_and_limit(struct amd64_pvt *pvt, int node_id,
+			       u64 *base, u64 *limit)
+{
+	*base = pvt->dram_base[node_id];
+	*limit = pvt->dram_limit[node_id];
+}
+
+/*
+ * Return 1 if the SysAddr given by sys_addr matches the base/limit associated
+ * with node_id
+ */
+static int amd64_base_limit_match(struct amd64_pvt *pvt,
+					u64 sys_addr, int node_id)
+{
+	u64 base, limit, addr;
+
+	amd64_get_base_and_limit(pvt, node_id, &base, &limit);
+
+	/* The K8 treats this as a 40-bit value.  However, bits 63-40 will be
+	 * all ones if the most significant implemented address bit is 1.
+	 * Here we discard bits 63-40.  See section 3.4.2 of AMD publication
+	 * 24592: AMD x86-64 Architecture Programmer's Manual Volume 1
+	 * Application Programming.
+	 */
+	addr = sys_addr & 0x000000ffffffffffull;
+
+	return (addr >= base) && (addr <= limit);
+}
+
+/*
+ * Attempt to map a SysAddr to a node. On success, return a pointer to the
+ * mem_ctl_info structure for the node that the SysAddr maps to.
+ *
+ * On failure, return NULL.
+ */
+static struct mem_ctl_info *find_mc_by_sys_addr(struct mem_ctl_info *mci,
+						u64 sys_addr)
+{
+	struct amd64_pvt *pvt;
+	int node_id;
+	u32 intlv_en, bits;
+
+	/*
+	 * Here we use the DRAM Base (section 3.4.4.1) and DRAM Limit (section
+	 * 3.4.4.2) registers to map the SysAddr to a node ID.
+	 */
+	pvt = mci->pvt_info;
+
+	/*
+	 * The value of this field should be the same for all DRAM Base
+	 * registers.  Therefore we arbitrarily choose to read it from the
+	 * register for node 0.
+	 */
+	intlv_en = pvt->dram_IntlvEn[0];
+
+	if (intlv_en == 0) {
+		for (node_id = 0; ; ) {
+			if (amd64_base_limit_match(pvt, sys_addr, node_id))
+				break;
+
+			if (++node_id >= DRAM_REG_COUNT)
+				goto err_no_match;
+		}
+		goto found;
+	}
+
+	if (unlikely((intlv_en != (0x01 << 8)) &&
+		     (intlv_en != (0x03 << 8)) &&
+		     (intlv_en != (0x07 << 8)))) {
+		amd64_printk(KERN_WARNING, "junk value of 0x%x extracted from "
+			     "IntlvEn field of DRAM Base Register for node 0: "
+			     "This probably indicates a BIOS bug.\n", intlv_en);
+		return NULL;
+	}
+
+	bits = (((u32) sys_addr) >> 12) & intlv_en;
+
+	for (node_id = 0; ; ) {
+		if ((pvt->dram_limit[node_id] & intlv_en) == bits)
+			break;	/* intlv_sel field matches */
+
+		if (++node_id >= DRAM_REG_COUNT)
+			goto err_no_match;
+	}
+
+	/* sanity test for sys_addr */
+	if (unlikely(!amd64_base_limit_match(pvt, sys_addr, node_id))) {
+		amd64_printk(KERN_WARNING,
+			  "%s(): sys_addr 0x%lx falls outside base/limit "
+			  "address range for node %d with node interleaving "
+			  "enabled.\n", __func__, (unsigned long)sys_addr,
+			  node_id);
+		return NULL;
+	}
+
+found:
+	return edac_mc_find(node_id);
+
+err_no_match:
+	debugf2("sys_addr 0x%lx doesn't match any node\n",
+		(unsigned long)sys_addr);
+
+	return NULL;
+}
-- 
1.6.2.4