[PATCH v3 3/3] hwmon: (peci/dimmtemp) Add Sapphire Rapids support

[Naresh Solanki <naresh.solanki@9elements.com>]

From: Patrick Rudolph <patrick.rudolph@9elements.com>

This patch extends the functionality of the hwmon (peci/dimmtemp) to
include support for Sapphire Rapids platform.

Sapphire Rapids can accommodate up to 8 CPUs, each with 16 DIMMs. To
accommodate this configuration, the maximum supported DIMM count is
increased, and the corresponding Sapphire Rapids ID and threshold code
are added.

The patch has been tested on a 4S system with 64 DIMMs installed.
Default thresholds are utilized for Sapphire Rapids, as accessing the
threshold requires accessing the UBOX device on Uncore bus 0, which can
only be achieved using MSR access. The non-PCI-compliant MMIO BARs are
not available for this purpose.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
---
Changes in V3:
- Update Acked-by in commit message.
Changes in V2:
- Update subject.
---
 drivers/hwmon/peci/dimmtemp.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/peci/dimmtemp.c b/drivers/hwmon/peci/dimmtemp.c
index ed968401f93c..edafbfd66fef 100644
--- a/drivers/hwmon/peci/dimmtemp.c
+++ b/drivers/hwmon/peci/dimmtemp.c
@@ -30,8 +30,10 @@
 #define DIMM_IDX_MAX_ON_ICX	2
 #define CHAN_RANK_MAX_ON_ICXD	4
 #define DIMM_IDX_MAX_ON_ICXD	2
+#define CHAN_RANK_MAX_ON_SPR	128
+#define DIMM_IDX_MAX_ON_SPR	2
 
-#define CHAN_RANK_MAX		CHAN_RANK_MAX_ON_HSX
+#define CHAN_RANK_MAX		CHAN_RANK_MAX_ON_SPR
 #define DIMM_IDX_MAX		DIMM_IDX_MAX_ON_HSX
 #define DIMM_NUMS_MAX		(CHAN_RANK_MAX * DIMM_IDX_MAX)
 
@@ -530,6 +532,15 @@ read_thresholds_icx(struct peci_dimmtemp *priv, int dimm_order, int chan_rank, u
 	return 0;
 }
 
+static int
+read_thresholds_spr(struct peci_dimmtemp *priv, int dimm_order, int chan_rank, u32 *data)
+{
+	/* Use defaults */
+	*data = (95 << 16) | (90 << 8);
+
+	return 0;
+}
+
 static const struct dimm_info dimm_hsx = {
 	.chan_rank_max	= CHAN_RANK_MAX_ON_HSX,
 	.dimm_idx_max	= DIMM_IDX_MAX_ON_HSX,
@@ -572,6 +583,13 @@ static const struct dimm_info dimm_icxd = {
 	.read_thresholds = &read_thresholds_icx,
 };
 
+static const struct dimm_info dimm_spr = {
+	.chan_rank_max	= CHAN_RANK_MAX_ON_SPR,
+	.dimm_idx_max	= DIMM_IDX_MAX_ON_SPR,
+	.min_peci_revision = 0x40,
+	.read_thresholds = &read_thresholds_spr,
+};
+
 static const struct auxiliary_device_id peci_dimmtemp_ids[] = {
 	{
 		.name = "peci_cpu.dimmtemp.hsx",
@@ -597,6 +615,10 @@ static const struct auxiliary_device_id peci_dimmtemp_ids[] = {
 		.name = "peci_cpu.dimmtemp.icxd",
 		.driver_data = (kernel_ulong_t)&dimm_icxd,
 	},
+	{
+		.name = "peci_cpu.dimmtemp.spr",
+		.driver_data = (kernel_ulong_t)&dimm_spr,
+	},
 	{ }
 };
 MODULE_DEVICE_TABLE(auxiliary, peci_dimmtemp_ids);
-- 
2.41.0