platform/x86: intel_pmc_core: Add LTR IGNORE debug feature

SPT LTR_IGN register provides a means to make the PMC ignore the LTR values
reported by the individual PCH devices.

echo <IP Offset> > /sys/kernel/debug/pmc_core/ltr_ignore.

When a particular IP Offset bit is set the PMC will ignore the LTR value
reported by the corresponding IP when the PMC performs the latency
coalescing.

IP Offset	IP Name
0		SPA
1		SPB
2		SATA
3		GBE
4		XHCI
5		RSVD
6		ME
7		EVA
8		SPC
9		Azalia/ADSP
10		RSVD
11		LPSS
12		SPD
13		SPE
14		Camera
15		ESPI
16		SCC
17		ISH

Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com>
[dvhart: pmc_core_ltr_ignore_write local declaration order cleanup]
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

diff --git a/drivers/platform/x86/intel_pmc_core.c b/drivers/platform/x86/intel_pmc_core.c
index bd1f4ef..0a81607 100644 (file)
--- a/drivers/platform/x86/intel_pmc_core.c
+++ b/drivers/platform/x86/intel_pmc_core.c
@@ -19,11 +19,12 @@
  */
 
 #include <linux/debugfs.h>
+#include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/pci.h>
-#include <linux/delay.h>
+#include <linux/uaccess.h>
 
 #include <asm/cpu_device_id.h>
 #include <asm/intel-family.h>
@@ -373,6 +374,53 @@ static const struct file_operations pmc_core_pll_ops = {
        .release        = single_release,
 };
 
+static ssize_t pmc_core_ltr_ignore_write(struct file *file, const char __user
+*userbuf, size_t count, loff_t *ppos)
+{
+       struct pmc_dev *pmcdev = &pmc;
+       u32 val, buf_size, fd;
+       int err = 0;
+
+       buf_size = count < 64 ? count : 64;
+       mutex_lock(&pmcdev->lock);
+
+       if (kstrtou32_from_user(userbuf, buf_size, 10, &val)) {
+               err = -EFAULT;
+               goto out_unlock;
+       }
+
+       if (val > NUM_IP_IGN_ALLOWED) {
+               err = -EINVAL;
+               goto out_unlock;
+       }
+
+       fd = pmc_core_reg_read(pmcdev, SPT_PMC_LTR_IGNORE_OFFSET);
+       fd |= (1U << val);
+       pmc_core_reg_write(pmcdev, SPT_PMC_LTR_IGNORE_OFFSET, fd);
+
+out_unlock:
+       mutex_unlock(&pmcdev->lock);
+       return err == 0 ? count : err;
+}
+
+static int pmc_core_ltr_ignore_show(struct seq_file *s, void *unused)
+{
+       return 0;
+}
+
+static int pmc_core_ltr_ignore_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, pmc_core_ltr_ignore_show, inode->i_private);
+}
+
+static const struct file_operations pmc_core_ltr_ignore_ops = {
+       .open           = pmc_core_ltr_ignore_open,
+       .read           = seq_read,
+       .write          = pmc_core_ltr_ignore_write,
+       .llseek         = seq_lseek,
+       .release        = single_release,
+};
+
 static void pmc_core_dbgfs_unregister(struct pmc_dev *pmcdev)
 {
        debugfs_remove_recursive(pmcdev->dbgfs_dir);
@@ -410,6 +458,13 @@ static int pmc_core_dbgfs_register(struct pmc_dev *pmcdev)
        if (!file)
                goto err;
 
+       file = debugfs_create_file("ltr_ignore",
+                                  S_IFREG | S_IRUGO, dir, pmcdev,
+                                  &pmc_core_ltr_ignore_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 07161fb..5a48e77 100644 (file)
--- a/drivers/platform/x86/intel_pmc_core.h
+++ b/drivers/platform/x86/intel_pmc_core.h
@@ -30,6 +30,7 @@
 #define SPT_PMC_PM_STS_OFFSET                  0x1c
 #define SPT_PMC_MTPMC_OFFSET                   0x20
 #define SPT_PMC_MFPMC_OFFSET                   0x38
+#define SPT_PMC_LTR_IGNORE_OFFSET              0x30C
 #define SPT_PMC_MPHY_CORE_STS_0                        0x1143
 #define SPT_PMC_MPHY_CORE_STS_1                        0x1142
 #define SPT_PMC_MPHY_COM_STS_0                 0x1155
@@ -41,6 +42,7 @@
 #define SPT_PMC_READ_DISABLE_BIT               0x16
 #define SPT_PMC_MSG_FULL_STS_BIT               0x18
 #define NUM_RETRIES                            100
+#define NUM_IP_IGN_ALLOWED                     17
 
 /* Sunrise Point: PGD PFET Enable Ack Status Registers */
 enum ppfear_regs {