iommu/tegra: smmu: debugfs for TLB/PTC statistics

Add debugfs entries to collect TLB/PTC statistics.

  $ echo "reset" > /sys/kernel/debug/smmu/mc/{tlb,ptc}
  $ echo "on" > /sys/kernel/debug/smmu/mc/{tlb,ptc}
  $ echo "off" > /sys/kernel/debug/smmu/mc/{tlb,ptc}
  $ cat /sys/kernel/debug/smmu/mc/{tlb,ptc}
  hit:0014910c miss:00014d22

  The above format is:
  hit:<HIT count><SPC>miss:<MISS count><SPC><CR+LF>

  fscanf(fp, "hit:%lx miss:%lx", &hit, &miss);

Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 190 insertions, 12 deletions

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 4ba325ab6262..95b4698abd3e 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -32,6 +32,8 @@
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_iommu.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
 
 #include <asm/page.h>
 #include <asm/cacheflush.h>
@@ -47,16 +49,29 @@
 #define SMMU_CONFIG_DISABLE                     0
 #define SMMU_CONFIG_ENABLE                      1
 
-#define SMMU_TLB_CONFIG                         0x14
-#define SMMU_TLB_CONFIG_STATS__MASK             (1 << 31)
-#define SMMU_TLB_CONFIG_STATS__ENABLE           (1 << 31)
+/* REVISIT: To support multiple MCs */
+enum {
+        _MC = 0,
+};
+
+enum {
+        _TLB = 0,
+        _PTC,
+};
+
+#define SMMU_CACHE_CONFIG_BASE                  0x14
+#define __SMMU_CACHE_CONFIG(mc, cache)          (SMMU_CACHE_CONFIG_BASE + 4 * cache)
+#define SMMU_CACHE_CONFIG(cache)                __SMMU_CACHE_CONFIG(_MC, cache)
+
+#define SMMU_CACHE_CONFIG_STATS_SHIFT           31
+#define SMMU_CACHE_CONFIG_STATS_ENABLE          (1 << SMMU_CACHE_CONFIG_STATS_SHIFT)
+#define SMMU_CACHE_CONFIG_STATS_TEST_SHIFT      30
+#define SMMU_CACHE_CONFIG_STATS_TEST            (1 << SMMU_CACHE_CONFIG_STATS_TEST_SHIFT)
+
 #define SMMU_TLB_CONFIG_HIT_UNDER_MISS__ENABLE  (1 << 29)
 #define SMMU_TLB_CONFIG_ACTIVE_LINES__VALUE     0x10
 #define SMMU_TLB_CONFIG_RESET_VAL               0x20000010
 
-#define SMMU_PTC_CONFIG                         0x18
-#define SMMU_PTC_CONFIG_STATS__MASK             (1 << 31)
-#define SMMU_PTC_CONFIG_STATS__ENABLE           (1 << 31)
 #define SMMU_PTC_CONFIG_CACHE__ENABLE           (1 << 29)
 #define SMMU_PTC_CONFIG_INDEX_MAP__PATTERN      0x3f
 #define SMMU_PTC_CONFIG_RESET_VAL               0x2000003f
@@ -86,10 +101,10 @@
 
 #define SMMU_ASID_SECURITY                      0x38
 
-#define SMMU_STATS_TLB_HIT_COUNT                0x1f0
-#define SMMU_STATS_TLB_MISS_COUNT               0x1f4
-#define SMMU_STATS_PTC_HIT_COUNT                0x1f8
-#define SMMU_STATS_PTC_MISS_COUNT               0x1fc
+#define SMMU_STATS_CACHE_COUNT_BASE             0x1f0
+
+#define SMMU_STATS_CACHE_COUNT(mc, cache, hitmiss)              \
+        (SMMU_STATS_CACHE_COUNT_BASE + 8 * cache + 4 * hitmiss)
 
 #define SMMU_TRANSLATION_ENABLE_0               0x228
 #define SMMU_TRANSLATION_ENABLE_1               0x22c
@@ -251,6 +266,8 @@ struct smmu_device {
         unsigned long translation_enable_2;
         unsigned long asid_security;
 
+        struct dentry *debugfs_root;
+
         struct device_node *ahb;
 
         int             num_as;
@@ -412,8 +429,8 @@ static int smmu_setup_regs(struct smmu_device *smmu)
         smmu_write(smmu, smmu->translation_enable_1, SMMU_TRANSLATION_ENABLE_1);
         smmu_write(smmu, smmu->translation_enable_2, SMMU_TRANSLATION_ENABLE_2);
         smmu_write(smmu, smmu->asid_security, SMMU_ASID_SECURITY);
-        smmu_write(smmu, SMMU_TLB_CONFIG_RESET_VAL, SMMU_TLB_CONFIG);
-        smmu_write(smmu, SMMU_PTC_CONFIG_RESET_VAL, SMMU_PTC_CONFIG);
+        smmu_write(smmu, SMMU_TLB_CONFIG_RESET_VAL, SMMU_CACHE_CONFIG(_TLB));
+        smmu_write(smmu, SMMU_PTC_CONFIG_RESET_VAL, SMMU_CACHE_CONFIG(_PTC));
 
         smmu_flush_regs(smmu, 1);
 
@@ -892,6 +909,164 @@ static struct iommu_ops smmu_iommu_ops = {
         .pgsize_bitmap  = SMMU_IOMMU_PGSIZES,
 };
 
+/* Should be in the order of enum */
+static const char * const smmu_debugfs_mc[] = { "mc", };
+static const char * const smmu_debugfs_cache[] = {  "tlb", "ptc", };
+
+static ssize_t smmu_debugfs_stats_write(struct file *file,
+                                        const char __user *buffer,
+                                        size_t count, loff_t *pos)
+{
+        struct smmu_device *smmu;
+        struct dentry *dent;
+        int i, cache, mc;
+        enum {
+                _OFF = 0,
+                _ON,
+                _RESET,
+        };
+        const char * const command[] = {
+                [_OFF]          = "off",
+                [_ON]           = "on",
+                [_RESET]        = "reset",
+        };
+        char str[] = "reset";
+        u32 val;
+        size_t offs;
+
+        count = min_t(size_t, count, sizeof(str));
+        if (copy_from_user(str, buffer, count))
+                return -EINVAL;
+
+        for (i = 0; i < ARRAY_SIZE(command); i++)
+                if (strncmp(str, command[i],
+                            strlen(command[i])) == 0)
+                        break;
+
+        if (i == ARRAY_SIZE(command))
+                return -EINVAL;
+
+        dent = file->f_dentry;
+        cache = (int)dent->d_inode->i_private;
+        mc = (int)dent->d_parent->d_inode->i_private;
+        smmu = dent->d_parent->d_parent->d_inode->i_private;
+
+        offs = SMMU_CACHE_CONFIG(cache);
+        val = smmu_read(smmu, offs);
+        switch (i) {
+        case _OFF:
+                val &= ~SMMU_CACHE_CONFIG_STATS_ENABLE;
+                val &= ~SMMU_CACHE_CONFIG_STATS_TEST;
+                smmu_write(smmu, val, offs);
+                break;
+        case _ON:
+                val |= SMMU_CACHE_CONFIG_STATS_ENABLE;
+                val &= ~SMMU_CACHE_CONFIG_STATS_TEST;
+                smmu_write(smmu, val, offs);
+                break;
+        case _RESET:
+                val |= SMMU_CACHE_CONFIG_STATS_TEST;
+                smmu_write(smmu, val, offs);
+                val &= ~SMMU_CACHE_CONFIG_STATS_TEST;
+                smmu_write(smmu, val, offs);
+                break;
+        default:
+                BUG();
+                break;
+        }
+
+        dev_dbg(smmu->dev, "%s() %08x, %08x @%08x\n", __func__,
+                val, smmu_read(smmu, offs), offs);
+
+        return count;
+}
+
+static int smmu_debugfs_stats_show(struct seq_file *s, void *v)
+{
+        struct smmu_device *smmu;
+        struct dentry *dent;
+        int i, cache, mc;
+        const char * const stats[] = { "hit", "miss", };
+
+        dent = d_find_alias(s->private);
+        cache = (int)dent->d_inode->i_private;
+        mc = (int)dent->d_parent->d_inode->i_private;
+        smmu = dent->d_parent->d_parent->d_inode->i_private;
+
+        for (i = 0; i < ARRAY_SIZE(stats); i++) {
+                u32 val;
+                size_t offs;
+
+                offs = SMMU_STATS_CACHE_COUNT(mc, cache, i);
+                val = smmu_read(smmu, offs);
+                seq_printf(s, "%s:%08x ", stats[i], val);
+
+                dev_dbg(smmu->dev, "%s() %s %08x @%08x\n", __func__,
+                        stats[i], val, offs);
+        }
+        seq_printf(s, "\n");
+
+        return 0;
+}
+
+static int smmu_debugfs_stats_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, smmu_debugfs_stats_show, inode);
+}
+
+static const struct file_operations smmu_debugfs_stats_fops = {
+        .open           = smmu_debugfs_stats_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+        .write          = smmu_debugfs_stats_write,
+};
+
+static void smmu_debugfs_delete(struct smmu_device *smmu)
+{
+        debugfs_remove_recursive(smmu->debugfs_root);
+}
+
+static void smmu_debugfs_create(struct smmu_device *smmu)
+{
+        int i;
+        struct dentry *root;
+
+        root = debugfs_create_file(dev_name(smmu->dev),
+                                   S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
+                                   NULL, smmu, NULL);
+        if (!root)
+                goto err_out;
+        smmu->debugfs_root = root;
+
+        for (i = 0; i < ARRAY_SIZE(smmu_debugfs_mc); i++) {
+                int j;
+                struct dentry *mc;
+
+                mc = debugfs_create_file(smmu_debugfs_mc[i],
+                                         S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
+                                         root, (void *)i, NULL);
+                if (!mc)
+                        goto err_out;
+
+                for (j = 0; j < ARRAY_SIZE(smmu_debugfs_cache); j++) {
+                        struct dentry *cache;
+
+                        cache = debugfs_create_file(smmu_debugfs_cache[j],
+                                                    S_IWUGO | S_IRUGO, mc,
+                                                    (void *)j,
+                                                    &smmu_debugfs_stats_fops);
+                        if (!cache)
+                                goto err_out;
+                }
+        }
+
+        return;
+
+err_out:
+        smmu_debugfs_delete(smmu);
+}
+
 static int tegra_smmu_suspend(struct device *dev)
 {
         struct smmu_device *smmu = dev_get_drvdata(dev);
@@ -996,6 +1171,7 @@ static int tegra_smmu_probe(struct platform_device *pdev)
         if (!smmu->avp_vector_page)
                 return -ENOMEM;
 
+        smmu_debugfs_create(smmu);
         smmu_handle = smmu;
         return 0;
 }
@@ -1005,6 +1181,8 @@ static int tegra_smmu_remove(struct platform_device *pdev)
         struct smmu_device *smmu = platform_get_drvdata(pdev);
         int i;
 
+        smmu_debugfs_delete(smmu);
+
         smmu_write(smmu, SMMU_CONFIG_DISABLE, SMMU_CONFIG);
         for (i = 0; i < smmu->num_as; i++)
                 free_pdir(&smmu->as[i]);