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Subject[PATCH] platform/x86: intel_pmc_core: Add Package C-states residency info
Date
This patch introduces a new debugfs entry to read current Package C-state
residency values and, one new kernel API to read the Package C-10 residency
counter.

Package C-state residency MSRs provide useful debug information about system
idle states. In idle states system must enter deeper Package C-states.

For example, on Intel Skylake/Kabylake based systems one should expect more
Package C-8 residency in "Idle Display On" scenarios compared to higher
Package C-states. With a self refresh display panel we must expect even more
deeper Package C-9/C-10 residencies indicating more power savings. Package
C-states depend not only on Core C-States but also on various IP blocks
power gating status and LTR values.

For Intel Core SoCs Package C-10 entry is a must for deeper sleep states
such as S0ix. "Suspend-to-idle" should ideally take this path:
PC0 -> PC10 -> S0ix. For S0ix debug, its logical to check for Package-C10
residency if for some reason system fails to enter S0ix.

Please refer to this link for MSR details:
https://software.intel.com/sites/default/files/managed/22/0d/335592-sdm-vol-4.pdf

Usage:
cat /sys/kernel/debug/pmc_core/package_cstate_residency
Package C2 : 0xec2e21735f
Package C3 : 0xc30113ba4
Package C6 : 0x9ef4be15c5
Package C7 : 0x1e011904
Package C8 : 0x3c5653cfe5a
Package C9 : 0x0
Package C10 : 0x16fff4289

Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com>
---
* Applied on top of "Make the driver PCH family agnostic" sent by Srinivas
* Tested on 4.13-rc4 as well as on the "testing" branch of the
platform/drivers/x86.

arch/x86/include/asm/pmc_core.h | 1 +
drivers/platform/x86/intel_pmc_core.c | 74 +++++++++++++++++++++++++++++++++++
drivers/platform/x86/intel_pmc_core.h | 1 +
3 files changed, 76 insertions(+)

diff --git a/arch/x86/include/asm/pmc_core.h b/arch/x86/include/asm/pmc_core.h
index d4855f11136d..99f48e63fafc 100644
--- a/arch/x86/include/asm/pmc_core.h
+++ b/arch/x86/include/asm/pmc_core.h
@@ -23,5 +23,6 @@

/* API to read SLP_S0_RESIDENCY counter */
int intel_pmc_slp_s0_counter_read(u32 *data);
+int intel_pkgc10_counter_read(u64 *data);

#endif /* _ASM_PMC_CORE_H */
diff --git a/drivers/platform/x86/intel_pmc_core.c b/drivers/platform/x86/intel_pmc_core.c
index 17e08b42b0a9..5eea99f24b10 100644
--- a/drivers/platform/x86/intel_pmc_core.c
+++ b/drivers/platform/x86/intel_pmc_core.c
@@ -29,11 +29,24 @@
#include <asm/cpu_device_id.h>
#include <asm/intel-family.h>
#include <asm/pmc_core.h>
+#include <asm/msr.h>

#include "intel_pmc_core.h"

static struct pmc_dev pmc;

+/* PKGC MSRs are common across Intel Core cpus */
+static const struct pmc_bit_map msr_map[] = {
+ {"Package C2", MSR_PKG_C2_RESIDENCY},
+ {"Package C3", MSR_PKG_C3_RESIDENCY},
+ {"Package C6", MSR_PKG_C6_RESIDENCY},
+ {"Package C7", MSR_PKG_C7_RESIDENCY},
+ {"Package C8", MSR_PKG_C8_RESIDENCY},
+ {"Package C9", MSR_PKG_C9_RESIDENCY},
+ {"Package C10", MSR_PKG_C10_RESIDENCY},
+ {},
+};
+
static const struct pmc_bit_map spt_pll_map[] = {
{"MIPI PLL", SPT_PMC_BIT_MPHY_CMN_LANE0},
{"GEN2 USB2PCIE2 PLL", SPT_PMC_BIT_MPHY_CMN_LANE1},
@@ -110,6 +123,7 @@ static const struct pmc_reg_map spt_reg_map = {
.pfear_sts = spt_pfear_map,
.mphy_sts = spt_mphy_map,
.pll_sts = spt_pll_map,
+ .msr_sts = msr_map,
.slp_s0_offset = SPT_PMC_SLP_S0_RES_COUNTER_OFFSET,
.ltr_ignore_offset = SPT_PMC_LTR_IGNORE_OFFSET,
.regmap_length = SPT_PMC_MMIO_REG_LEN,
@@ -147,6 +161,26 @@ static inline u32 pmc_core_adjust_slp_s0_step(u32 value)
}

/**
+ * intel_pkgc10_counter_read() - Read Package C10 residency.
+ * @data: Out param that contains current PC10 count by reading MSR 0x632
+ *
+ * MSR_PKG_C10_RESIDENCY counter counts at the same frequency as the TSC.
+ * BIT 0:59 represent the value since the last reset that this package is in
+ * processor specific C10 states.
+ * BIT 63:60 are reserved.
+ *
+ * Return: an error code or 0 on success.
+ */
+int intel_pkgc10_counter_read(u64 *data)
+{
+ if (!data)
+ return -EINVAL;
+
+ return rdmsrl_safe(MSR_PKG_C10_RESIDENCY, data);
+}
+EXPORT_SYMBOL_GPL(intel_pkgc10_counter_read);
+
+/**
* intel_pmc_slp_s0_counter_read() - Read SLP_S0 residency.
* @data: Out param that contains current SLP_S0 count.
*
@@ -430,6 +464,39 @@ static const struct file_operations pmc_core_ltr_ignore_ops = {
.release = single_release,
};

+static int pmc_core_pkgc_show(struct seq_file *s, void *unused)
+{
+ struct pmc_dev *pmcdev = s->private;
+ const struct pmc_bit_map *map = pmcdev->map->msr_sts;
+ u64 pcstate_count;
+ int index, err;
+
+ for (index = 0; map[index].name ; index++) {
+ err = rdmsrl_safe(map[index].bit_mask, &pcstate_count);
+ if (err) {
+ pr_debug("Failed to read %s residency MSR",
+ map[index].name);
+ return err;
+ }
+ seq_printf(s, "%s\t : 0x%llx\n", map[index].name,
+ pcstate_count);
+ }
+
+ return 0;
+}
+
+static int pmc_core_pkgc_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, pmc_core_pkgc_show, inode->i_private);
+}
+
+static const struct file_operations pmc_core_pkgc_ops = {
+ .open = pmc_core_pkgc_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
static void pmc_core_dbgfs_unregister(struct pmc_dev *pmcdev)
{
debugfs_remove_recursive(pmcdev->dbgfs_dir);
@@ -474,6 +541,13 @@ static int pmc_core_dbgfs_register(struct pmc_dev *pmcdev)
if (!file)
goto err;

+ file = debugfs_create_file("package_cstate_residency",
+ S_IFREG | S_IRUGO, dir, pmcdev,
+ &pmc_core_pkgc_ops);
+
+ if (!file)
+ goto err;
+
return 0;
err:
pmc_core_dbgfs_unregister(pmcdev);
diff --git a/drivers/platform/x86/intel_pmc_core.h b/drivers/platform/x86/intel_pmc_core.h
index 3d225a9cc09f..4423b84c53c0 100644
--- a/drivers/platform/x86/intel_pmc_core.h
+++ b/drivers/platform/x86/intel_pmc_core.h
@@ -150,6 +150,7 @@ struct pmc_reg_map {
const struct pmc_bit_map *pfear_sts;
const struct pmc_bit_map *mphy_sts;
const struct pmc_bit_map *pll_sts;
+ const struct pmc_bit_map *msr_sts;
const u32 slp_s0_offset;
const u32 ltr_ignore_offset;
const u32 base_address;
--
2.7.4
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