platform/x86: intel_pmc_core: ModPhy core lanes pg status

The PCH implements a number of High Speed I/O (HSIO) lanes that are split
between PCIe*, USB 3.0, SATA, GbE, USB OTG and SSIC. This patch shows the
current power gating status of the available ModPhy Core lanes. This is
done by sending a message to the PMC (MTPMC) that contains the XRAM
register offset for the MPHY_CORE_STS_0 and MPHY_CORE_STS_1 and then by
reading the response sent by the PMC (MFPMC).

While enabling low power modes we often encounter situations when the
ModPhy lanes are not power gated and it becomes hard to debug which lane is
active and which is not in the absence of an external hardware debugger
(JTAG/ITP). This patch eliminates the dependency on an external hardware
debugger for reading the ModPhy Lanes power gating status.

This patch requires PMC_READ_DISABLE setting to be disabled in the platform
bios.

cat /sys/kernel/debug/pmc_core/mphy_lanes_power_gating_status

Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

1 files changed, 144 insertions, 1 deletions

diff --git a/drivers/platform/x86/intel_pmc_core.c b/drivers/platform/x86/intel_pmc_core.c
index 14aac633479a..1d9d340492d8 100644
--- a/drivers/platform/x86/intel_pmc_core.c
+++ b/drivers/platform/x86/intel_pmc_core.c
@@ -23,6 +23,7 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/pci.h>
+#include <linux/delay.h>
 
 #include <asm/cpu_device_id.h>
 #include <asm/intel-family.h>
@@ -32,6 +33,26 @@
 
 static struct pmc_dev pmc;
 
+static const struct pmc_bit_map spt_mphy_map[] = {
+	{"MPHY CORE LANE 0",           SPT_PMC_BIT_MPHY_LANE0},
+	{"MPHY CORE LANE 1",           SPT_PMC_BIT_MPHY_LANE1},
+	{"MPHY CORE LANE 2",           SPT_PMC_BIT_MPHY_LANE2},
+	{"MPHY CORE LANE 3",           SPT_PMC_BIT_MPHY_LANE3},
+	{"MPHY CORE LANE 4",           SPT_PMC_BIT_MPHY_LANE4},
+	{"MPHY CORE LANE 5",           SPT_PMC_BIT_MPHY_LANE5},
+	{"MPHY CORE LANE 6",           SPT_PMC_BIT_MPHY_LANE6},
+	{"MPHY CORE LANE 7",           SPT_PMC_BIT_MPHY_LANE7},
+	{"MPHY CORE LANE 8",           SPT_PMC_BIT_MPHY_LANE8},
+	{"MPHY CORE LANE 9",           SPT_PMC_BIT_MPHY_LANE9},
+	{"MPHY CORE LANE 10",          SPT_PMC_BIT_MPHY_LANE10},
+	{"MPHY CORE LANE 11",          SPT_PMC_BIT_MPHY_LANE11},
+	{"MPHY CORE LANE 12",          SPT_PMC_BIT_MPHY_LANE12},
+	{"MPHY CORE LANE 13",          SPT_PMC_BIT_MPHY_LANE13},
+	{"MPHY CORE LANE 14",          SPT_PMC_BIT_MPHY_LANE14},
+	{"MPHY CORE LANE 15",          SPT_PMC_BIT_MPHY_LANE15},
+	{},
+};
+
 static const struct pmc_bit_map spt_pfear_map[] = {
 	{"PMC",				SPT_PMC_BIT_PMC},
 	{"OPI-DMI",			SPT_PMC_BIT_OPI},
@@ -78,6 +99,7 @@ static const struct pmc_bit_map spt_pfear_map[] = {
 
 static const struct pmc_reg_map spt_reg_map = {
 	.pfear_sts = spt_pfear_map,
+	.mphy_sts = spt_mphy_map,
 };
 
 static const struct pci_device_id pmc_pci_ids[] = {
@@ -96,6 +118,12 @@ static inline u32 pmc_core_reg_read(struct pmc_dev *pmcdev, int reg_offset)
 	return readl(pmcdev->regbase + reg_offset);
 }
 
+static inline void pmc_core_reg_write(struct pmc_dev *pmcdev, int
+							reg_offset, u32 val)
+{
+	writel(val, pmcdev->regbase + reg_offset);
+}
+
 static inline u32 pmc_core_adjust_slp_s0_step(u32 value)
 {
 	return value * SPT_PMC_SLP_S0_RES_COUNTER_STEP;
@@ -144,6 +172,16 @@ static int pmc_core_dev_state_get(void *data, u64 *val)
 
 DEFINE_DEBUGFS_ATTRIBUTE(pmc_core_dev_state, pmc_core_dev_state_get, NULL, "%llu\n");
 
+static int pmc_core_check_read_lock_bit(void)
+{
+	struct pmc_dev *pmcdev = &pmc;
+	u32 value;
+
+	value = pmc_core_reg_read(pmcdev, SPT_PMC_PM_CFG_OFFSET);
+	return test_bit(SPT_PMC_READ_DISABLE_BIT,
+			(unsigned long *)&value);
+}
+
 #if IS_ENABLED(CONFIG_DEBUG_FS)
 static void pmc_core_display_map(struct seq_file *s, int index,
 				 u8 pf_reg, const struct pmc_bit_map *pf_map)
@@ -183,6 +221,102 @@ static const struct file_operations pmc_core_ppfear_ops = {
 	.release        = single_release,
 };
 
+/* This function should return link status, 0 means ready */
+static int pmc_core_mtpmc_link_status(void)
+{
+	struct pmc_dev *pmcdev = &pmc;
+	u32 value;
+
+	value = pmc_core_reg_read(pmcdev, SPT_PMC_PM_STS_OFFSET);
+	return test_bit(SPT_PMC_MSG_FULL_STS_BIT,
+			(unsigned long *)&value);
+}
+
+static int pmc_core_send_msg(u32 *addr_xram)
+{
+	struct pmc_dev *pmcdev = &pmc;
+	u32 dest;
+	int timeout;
+
+	for (timeout = NUM_RETRIES; timeout > 0; timeout--) {
+		if (pmc_core_mtpmc_link_status() == 0)
+			break;
+		msleep(5);
+	}
+
+	if (timeout <= 0 && pmc_core_mtpmc_link_status())
+		return -EBUSY;
+
+	dest = (*addr_xram & MTPMC_MASK) | (1U << 1);
+	pmc_core_reg_write(pmcdev, SPT_PMC_MTPMC_OFFSET, dest);
+	return 0;
+}
+
+static int pmc_core_mphy_pg_sts_show(struct seq_file *s, void *unused)
+{
+	struct pmc_dev *pmcdev = s->private;
+	const struct pmc_bit_map *map = pmcdev->map->mphy_sts;
+	u32 mphy_core_reg_low, mphy_core_reg_high;
+	u32 val_low, val_high;
+	int index, err = 0;
+
+	if (pmcdev->pmc_xram_read_bit) {
+		seq_puts(s, "Access denied: please disable PMC_READ_DISABLE setting in BIOS.");
+		return 0;
+	}
+
+	mphy_core_reg_low  = (SPT_PMC_MPHY_CORE_STS_0 << 16);
+	mphy_core_reg_high = (SPT_PMC_MPHY_CORE_STS_1 << 16);
+
+	mutex_lock(&pmcdev->lock);
+
+	if (pmc_core_send_msg(&mphy_core_reg_low) != 0) {
+		err = -EBUSY;
+		goto out_unlock;
+	}
+
+	msleep(10);
+	val_low = pmc_core_reg_read(pmcdev, SPT_PMC_MFPMC_OFFSET);
+
+	if (pmc_core_send_msg(&mphy_core_reg_high) != 0) {
+		err = -EBUSY;
+		goto out_unlock;
+	}
+
+	msleep(10);
+	val_high = pmc_core_reg_read(pmcdev, SPT_PMC_MFPMC_OFFSET);
+
+	for (index = 0; map[index].name && index < 8; index++) {
+		seq_printf(s, "%-32s\tState: %s\n",
+			   map[index].name,
+			   map[index].bit_mask & val_low ? "Not power gated" :
+			   "Power gated");
+	}
+
+	for (index = 8; map[index].name; index++) {
+		seq_printf(s, "%-32s\tState: %s\n",
+			   map[index].name,
+			   map[index].bit_mask & val_high ? "Not power gated" :
+			   "Power gated");
+	}
+
+out_unlock:
+	mutex_unlock(&pmcdev->lock);
+	return err;
+}
+
+static int pmc_core_mphy_pg_sts_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pmc_core_mphy_pg_sts_show, inode->i_private);
+}
+
+static const struct file_operations pmc_core_mphy_pg_ops = {
+	.open           = pmc_core_mphy_pg_sts_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);
@@ -208,6 +342,12 @@ static int pmc_core_dbgfs_register(struct pmc_dev *pmcdev)
 	if (!file)
 		goto err;
 
+	file = debugfs_create_file("mphy_core_lanes_power_gating_status",
+				   S_IFREG | S_IRUGO, dir, pmcdev,
+				   &pmc_core_mphy_pg_ops);
+	if (!file)
+		goto err;
+
 	return 0;
 
 err:
@@ -271,11 +411,14 @@ static int pmc_core_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return -ENOMEM;
 	}
 
+	mutex_init(&pmcdev->lock);
+	pmcdev->pmc_xram_read_bit = pmc_core_check_read_lock_bit();
+	pmcdev->map = map;
+
 	err = pmc_core_dbgfs_register(pmcdev);
 	if (err < 0)
 		dev_warn(&dev->dev, "PMC Core: debugfs register failed.\n");
 
-	pmcdev->map = map;
 	pmc.has_slp_s0_res = true;
 	return 0;
 }