[Intel-gfx] [PATCH 2/7] drm/i915/hwmon: Add HWMON current voltage support

Badal Nilawar
2022-08-18T19:37:36Z

From: Riana Tauro <riana.tauro@intel.com>

Use i915 HWMON subsystem to display current input voltage.

v2:
- Updated date and kernel version in feature description
- Fixed review comments (Ashutosh)
v3: Use macro HWMON_CHANNEL_INFO to define hwmon channel (Guenter)
v4:
- Fixed review comments (Ashutosh)
- Use hwm_ prefix for static functions (Ashutosh)

Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Riana Tauro <riana.tauro@intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
---
.../ABI/testing/sysfs-driver-intel-i915-hwmon | 7 +++
drivers/gpu/drm/i915/gt/intel_gt_regs.h | 3 ++
drivers/gpu/drm/i915/i915_hwmon.c | 47 +++++++++++++++++++
3 files changed, 57 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon

diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
new file mode 100644
index 000000000000..24c4b7477d51
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
@@ -0,0 +1,7 @@
+What: /sys/devices/.../hwmon/hwmon/in0_input
+Date: June 2022
+KernelVersion: 5.19
+Contact: dri-devel@lists.freedesktop.org
+Description: RO. Current Voltage in millivolt.
+
+ Only supported for particular Intel i915 graphics platforms.
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
index 94f9ddcfb3a5..5d4fbda4d326 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
@@ -1508,6 +1508,9 @@
#define VLV_RENDER_C0_COUNT _MMIO(0x138118)
#define VLV_MEDIA_C0_COUNT _MMIO(0x13811c)

+#define GEN12_RPSTAT1 _MMIO(0x1381b4)
+#define GEN12_VOLTAGE_MASK REG_GENMASK(10, 0)
+
#define GEN11_GT_INTR_DW(x) _MMIO(0x190018 + ((x) * 4))
#define GEN11_CSME (31)
#define GEN11_GUNIT (28)
diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
index 5b80a0f024f0..1893efe796a4 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.c
+++ b/drivers/gpu/drm/i915/i915_hwmon.c
@@ -10,8 +10,10 @@
#include "i915_drv.h"
#include "i915_hwmon.h"
#include "intel_mchbar_regs.h"
+#include "gt/intel_gt_regs.h"

struct hwm_reg {
+ i915_reg_t gt_perf_status;
};

struct hwm_drvdata {
@@ -28,14 +30,49 @@ struct i915_hwmon {
};

static const struct hwmon_channel_info *hwm_info[] = {
+ HWMON_CHANNEL_INFO(in, HWMON_I_INPUT),
NULL
};

+static umode_t
+hwm_in_is_visible(const struct hwm_drvdata *ddat, u32 attr)
+{
+ switch (attr) {
+ case hwmon_in_input:
+ return i915_mmio_reg_valid(ddat->hwmon->rg.gt_perf_status) ? 0444 : 0;
+ default:
+ return 0;
+ }
+}
+
+static int
+hwm_in_read(struct hwm_drvdata *ddat, u32 attr, long *val)
+{
+ struct i915_hwmon *hwmon = ddat->hwmon;
+ intel_wakeref_t wakeref;
+ u32 reg_value;
+
+ switch (attr) {
+ case hwmon_in_input:
+ with_intel_runtime_pm(ddat->uncore->rpm, wakeref)
+ reg_value = intel_uncore_read(ddat->uncore, hwmon->rg.gt_perf_status);
+ /* In units of 2.5 millivolt */
+ *val = DIV_ROUND_CLOSEST(REG_FIELD_GET(GEN12_VOLTAGE_MASK, reg_value) * 25, 10);
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
static umode_t
hwm_is_visible(const void *drvdata, enum hwmon_sensor_types type,
u32 attr, int channel)
{
+ struct hwm_drvdata *ddat = (struct hwm_drvdata *)drvdata;
+
switch (type) {
+ case hwmon_in:
+ return hwm_in_is_visible(ddat, attr);
default:
return 0;
}
@@ -45,7 +82,11 @@ static int
hwm_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
int channel, long *val)
{
+ struct hwm_drvdata *ddat = dev_get_drvdata(dev);
+
switch (type) {
+ case hwmon_in:
+ return hwm_in_read(ddat, attr, val);
default:
return -EOPNOTSUPP;
}
@@ -75,6 +116,12 @@ static const struct hwmon_chip_info hwm_chip_info = {
static void
hwm_get_preregistration_info(struct drm_i915_private *i915)
{
+ struct i915_hwmon *hwmon = i915->hwmon;
+
+ if (IS_DG1(i915) || IS_DG2(i915))
+ hwmon->rg.gt_perf_status = GEN12_RPSTAT1;
+ else
+ hwmon->rg.gt_perf_status = INVALID_MMIO_REG;
}

void i915_hwmon_register(struct drm_i915_private *i915)
--
2.25.1