[PATCH V4] platform/x86: intel_pmc_core: Add CNP SLPS0 debug registers

["David E. Box" <david.e.box@linux.intel.com>]

From: <david.e.box@intel.com>

Adds debugfs access to registers in the Cannonlake PCH PMC that are
useful for debugging #SLP_S0 signal assertion and other low power
related activities. Device pm states are latched in these registers
whenever the package enters C10 and can be read from slp_s0_debug_status.
The pm states may also be latched by writing 1 to slp_s0_debug_latch
which will immediately capture the current state on the next read of
slp_s0_debug_status.

Signed-off-by: Box, David E <david.e.box@intel.com>
---
V4:
	- rename slp_s0_dbg string to slp_s0_debug for consistency
	- ADD ISCLK prefix to MAIN_PLL and OC_PLL
V3:
	- use null terminator in bit_map array
	- replaced ternary operator with if/else
	- Removed space fixes on old code
V2:
	- Clear latch bit after use
	- Pass pmc_dev as parameter
	- Use DEFINE_SHOW_ATTRIBUTE macro
 drivers/platform/x86/intel_pmc_core.c | 120 ++++++++++++++++++++++++++++++++++
 drivers/platform/x86/intel_pmc_core.h |   6 ++
 2 files changed, 126 insertions(+)

diff --git a/drivers/platform/x86/intel_pmc_core.c b/drivers/platform/x86/intel_pmc_core.c
index 43bbe74..d00fee2 100644
--- a/drivers/platform/x86/intel_pmc_core.c
+++ b/drivers/platform/x86/intel_pmc_core.c
@@ -196,9 +196,67 @@ static const struct pmc_bit_map cnp_pfear_map[] = {
 	{}
 };
 
+static const struct pmc_bit_map cnp_slps0_dbg0_map[] = {
+	{"AUDIO_D3",		BIT(0)},
+	{"OTG_D3",		BIT(1)},
+	{"XHCI_D3",		BIT(2)},
+	{"LPIO_D3",		BIT(3)},
+	{"SDX_D3",		BIT(4)},
+	{"SATA_D3",		BIT(5)},
+	{"UFS0_D3",		BIT(6)},
+	{"UFS1_D3",		BIT(7)},
+	{"EMMC_D3",		BIT(8)},
+	{}
+};
+
+static const struct pmc_bit_map cnp_slps0_dbg1_map[] = {
+	{"SDIO_PLL_OFF",	BIT(0)},
+	{"USB2_PLL_OFF",	BIT(1)},
+	{"AUDIO_PLL_OFF",	BIT(2)},
+	{"ISCLK_OC_PLL_OFF",	BIT(3)},
+	{"ISCLK_MAIN_PLL_OFF",	BIT(4)},
+	{"XOSC_OFF",		BIT(5)},
+	{"LPC_CLKS_GATED",	BIT(6)},
+	{"PCIE_CLKREQS_IDLE",	BIT(7)},
+	{"AUDIO_ROSC_OFF",	BIT(8)},
+	{"HPET_XOSC_CLK_REQ",	BIT(9)},
+	{"PMC_ROSC_SLOW_CLK",	BIT(10)},
+	{"AON2_ROSC_GATED",	BIT(11)},
+	{"CLKACKS_DEASSERTED",	BIT(12)},
+	{}
+};
+
+static const struct pmc_bit_map cnp_slps0_dbg2_map[] = {
+	{"MPHY_CORE_GATED",	BIT(0)},
+	{"CSME_GATED",		BIT(1)},
+	{"USB2_SUS_GATED",	BIT(2)},
+	{"DYN_FLEX_IO_IDLE",	BIT(3)},
+	{"GBE_NO_LINK",		BIT(4)},
+	{"THERM_SEN_DISABLED",	BIT(5)},
+	{"PCIE_LOW_POWER",	BIT(6)},
+	{"ISH_VNNAON_REQ_ACT",	BIT(7)},
+	{"ISH_VNN_REQ_ACT",	BIT(8)},
+	{"CNV_VNNAON_REQ_ACT",	BIT(9)},
+	{"CNV_VNN_REQ_ACT",	BIT(10)},
+	{"NPK_VNNON_REQ_ACT",	BIT(11)},
+	{"PMSYNC_STATE_IDLE",	BIT(12)},
+	{"ALST_GT_THRES",	BIT(13)},
+	{"PMC_ARC_PG_READY",	BIT(14)},
+	{}
+};
+
+static const struct pmc_bit_map *cnp_slps0_dbg_maps[] = {
+	cnp_slps0_dbg0_map,
+	cnp_slps0_dbg1_map,
+	cnp_slps0_dbg2_map,
+	NULL,
+};
+
 static const struct pmc_reg_map cnp_reg_map = {
 	.pfear_sts = cnp_pfear_map,
 	.slp_s0_offset = CNP_PMC_SLP_S0_RES_COUNTER_OFFSET,
+	.slps0_dbg_maps = cnp_slps0_dbg_maps,
+	.slps0_dbg_offset = CNP_PMC_SLPS0_DBG_OFFSET,
 	.ltr_ignore_offset = CNP_PMC_LTR_IGNORE_OFFSET,
 	.regmap_length = CNP_PMC_MMIO_REG_LEN,
 	.ppfear0_offset = CNP_PMC_HOST_PPFEAR0A,
@@ -252,6 +310,8 @@ static int pmc_core_check_read_lock_bit(void)
 }
 
 #if IS_ENABLED(CONFIG_DEBUG_FS)
+static bool slps0_dbg_latch;
+
 static void pmc_core_display_map(struct seq_file *s, int index,
 				 u8 pf_reg, const struct pmc_bit_map *pf_map)
 {
@@ -481,6 +541,57 @@ static const struct file_operations pmc_core_ltr_ignore_ops = {
 	.release        = single_release,
 };
 
+static void pmc_core_slps0_dbg_latch(struct pmc_dev *pmcdev, bool reset)
+{
+	const struct pmc_reg_map *map = pmcdev->map;
+	u32 fd;
+
+	mutex_lock(&pmcdev->lock);
+
+	if (!reset && !slps0_dbg_latch)
+		goto out_unlock;
+
+	fd = pmc_core_reg_read(pmcdev, map->slps0_dbg_offset);
+	if (reset)
+		fd &= ~CNP_PMC_LATCH_SLPS0_EVENTS;
+	else
+		fd |= CNP_PMC_LATCH_SLPS0_EVENTS;
+	pmc_core_reg_write(pmcdev, map->slps0_dbg_offset, fd);
+
+	slps0_dbg_latch = 0;
+
+out_unlock:
+	mutex_unlock(&pmcdev->lock);
+}
+
+static int pmc_core_slps0_dbg_show(struct seq_file *s, void *unused)
+{
+	struct pmc_dev *pmcdev = s->private;
+	const struct pmc_bit_map **maps = pmcdev->map->slps0_dbg_maps;
+	const struct pmc_bit_map *map;
+	int offset;
+	u32 data;
+
+	pmc_core_slps0_dbg_latch(pmcdev, false);
+	offset = pmcdev->map->slps0_dbg_offset;
+	while (*maps) {
+		map = *maps;
+		data = pmc_core_reg_read(pmcdev, offset);
+		offset += 4;
+		while (map->name) {
+			seq_printf(s, "SLP_S0_DBG: %-32s\tState: %s\n",
+				   map->name,
+				   data & map->bit_mask ?
+				   "Yes" : "No");
+			++map;
+		}
+		++maps;
+	}
+	pmc_core_slps0_dbg_latch(pmcdev, true);
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(pmc_core_slps0_dbg);
+
 static void pmc_core_dbgfs_unregister(struct pmc_dev *pmcdev)
 {
 	debugfs_remove_recursive(pmcdev->dbgfs_dir);
@@ -514,6 +625,15 @@ static int pmc_core_dbgfs_register(struct pmc_dev *pmcdev)
 				    0444, dir, pmcdev,
 				    &pmc_core_mphy_pg_ops);
 
+	if (pmcdev->map->slps0_dbg_maps) {
+		debugfs_create_file("slp_s0_debug_status", 0444,
+				    dir, pmcdev,
+				    &pmc_core_slps0_dbg_fops);
+
+		debugfs_create_bool("slp_s0_debug_latch", 0644,
+				    dir, &slps0_dbg_latch);
+	}
+
 	return 0;
 }
 #else
diff --git a/drivers/platform/x86/intel_pmc_core.h b/drivers/platform/x86/intel_pmc_core.h
index 5fa5f97..93a7e99 100644
--- a/drivers/platform/x86/intel_pmc_core.h
+++ b/drivers/platform/x86/intel_pmc_core.h
@@ -127,12 +127,14 @@ enum ppfear_regs {
 #define CNP_PMC_SLP_S0_RES_COUNTER_OFFSET      0x193C
 #define CNP_PMC_LTR_IGNORE_OFFSET              0x1B0C
 #define CNP_PMC_PM_CFG_OFFSET                  0x1818
+#define CNP_PMC_SLPS0_DBG_OFFSET		0x10B4
 /* Cannonlake: PGD PFET Enable Ack Status Register(s) start */
 #define CNP_PMC_HOST_PPFEAR0A                  0x1D90
 
 #define CNP_PMC_MMIO_REG_LEN                   0x2000
 #define CNP_PPFEAR_NUM_ENTRIES                 8
 #define CNP_PMC_READ_DISABLE_BIT               22
+#define CNP_PMC_LATCH_SLPS0_EVENTS		BIT(31)
 
 struct pmc_bit_map {
 	const char *name;
@@ -145,6 +147,7 @@ struct pmc_bit_map {
  * @pfear_sts:		Maps name of IP block to PPFEAR* bit
  * @mphy_sts:		Maps name of MPHY lane to MPHY status lane status bit
  * @pll_sts:		Maps name of PLL to corresponding bit status
+ * @slps0_dbg_maps:	Array of SLP_S0_DBG* registers containing debug info
  * @slp_s0_offset:	PWRMBASE offset to read SLP_S0 residency
  * @ltr_ignore_offset:	PWRMBASE offset to read/write LTR ignore bit
  * @regmap_length:	Length of memory to map from PWRMBASE address to access
@@ -153,6 +156,7 @@ struct pmc_bit_map {
  *			PPFEAR
  * @pm_cfg_offset:	PWRMBASE offset to PM_CFG register
  * @pm_read_disable_bit: Bit index to read PMC_READ_DISABLE
+ * @slps0_dbg_offset:	PWRMBASE offset to SLP_S0_DEBUG_REG*
  *
  * Each PCH has unique set of register offsets and bit indexes. This structure
  * captures them to have a common implementation.
@@ -161,6 +165,7 @@ 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 **slps0_dbg_maps;
 	const u32 slp_s0_offset;
 	const u32 ltr_ignore_offset;
 	const int regmap_length;
@@ -168,6 +173,7 @@ struct pmc_reg_map {
 	const int ppfear_buckets;
 	const u32 pm_cfg_offset;
 	const int pm_read_disable_bit;
+	const u32 slps0_dbg_offset;
 };
 
 /**
-- 
2.7.4