[PATCH 24/31] drm/i915/slpc: Add debugfs support to read/write/revert the parameters

Sagar Arun Kamble
2017-09-19T17:39:30Z

This patch adds two debugfs interfaces:
1. i915_slpc_paramlist: List of all parameters that Host can configure.
Currently listing id and description of each.
2. i915_slpc_param_ctl: This allows to change the parameters. Syntax is:
echo "write <id> <value>" > i915_slpc_param_ctl.
echo "read <id>" > i915_slpc_param_ctl; cat i915_slpc_param_ctl
revert allows to set to default SLPC internal values. Syntax is:
echo "revert <id>" > i915_slpc_param_ctl.

Added support to set/read parameters and unset the parameters which will
revert them to default SLPC internal values. Also added RPM ref. cover
around set/unset calls. Explicit SLPC reset is needed on setting/unsetting
some of the parameters.

Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
---
drivers/gpu/drm/i915/i915_debugfs.c | 19 +++++
drivers/gpu/drm/i915/intel_slpc.c | 158 ++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_slpc.h | 6 ++
3 files changed, 183 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index dbfe185..0a04f3d 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2352,6 +2352,23 @@ static int i915_huc_load_status_info(struct seq_file *m, void *data)
return 0;
}

+static int i915_slpc_paramlist_info(struct seq_file *m, void *data)
+{
+ struct drm_i915_private *dev_priv = node_to_i915(m->private);
+ int i;
+
+ if (!dev_priv->guc.slpc.active) {
+ seq_puts(m, "SLPC not active\n");
+ return 0;
+ }
+
+ seq_puts(m, "Param id\tParam description\n");
+ for (i = 0; i < SLPC_MAX_PARAM; i++)
+ seq_printf(m, "%8d\t%s\n", slpc_paramlist[i].id,
+ slpc_paramlist[i].description);
+ return 0;
+}
+
static int i915_guc_load_status_info(struct seq_file *m, void *data)
{
struct drm_i915_private *dev_priv = node_to_i915(m->private);
@@ -4881,6 +4898,7 @@ static int i915_hpd_storm_ctl_open(struct inode *inode, struct file *file)
{"i915_guc_load_err_log_dump", i915_guc_log_dump, 0, (void *)1},
{"i915_guc_stage_pool", i915_guc_stage_pool, 0},
{"i915_huc_load_status", i915_huc_load_status_info, 0},
+ {"i915_slpc_paramlist", i915_slpc_paramlist_info, 0},
{"i915_frequency_info", i915_frequency_info, 0},
{"i915_hangcheck_info", i915_hangcheck_info, 0},
{"i915_reset_info", i915_reset_info, 0},
@@ -4944,6 +4962,7 @@ static int i915_hpd_storm_ctl_open(struct inode *inode, struct file *file)
{"i915_dp_test_type", &i915_displayport_test_type_fops},
{"i915_dp_test_active", &i915_displayport_test_active_fops},
{"i915_guc_log_control", &i915_guc_log_control_fops},
+ {"i915_slpc_param_ctl", &i915_slpc_param_ctl_fops},
{"i915_hpd_storm_ctl", &i915_hpd_storm_ctl_fops},
{"i915_ipc_status", &i915_ipc_status_fops}
};
diff --git a/drivers/gpu/drm/i915/intel_slpc.c b/drivers/gpu/drm/i915/intel_slpc.c
index d0fd402..0c094f0 100644
--- a/drivers/gpu/drm/i915/intel_slpc.c
+++ b/drivers/gpu/drm/i915/intel_slpc.c
@@ -25,6 +25,8 @@
#include <asm/msr-index.h>
#include "i915_drv.h"
#include "intel_uc.h"
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>

struct slpc_param slpc_paramlist[SLPC_MAX_PARAM] = {
{SLPC_PARAM_TASK_ENABLE_GTPERF, "Enable task GTPERF"},
@@ -684,3 +686,159 @@ void intel_slpc_disable(struct intel_slpc *slpc)

slpc->active = false;
}
+
+static int slpc_param_ctl_show(struct seq_file *m, void *data)
+{
+ struct drm_i915_private *dev_priv = m->private;
+ struct intel_slpc *slpc = &dev_priv->guc.slpc;
+
+ if (!slpc->active) {
+ seq_puts(m, "SLPC not active\n");
+ return 0;
+ }
+
+ seq_printf(m, "%s=%u, override=%s\n",
+ slpc_paramlist[slpc->debug_param_id].description,
+ slpc->debug_param_value,
+ yesno(!!slpc->debug_param_override));
+
+ return 0;
+}
+
+static int slpc_param_ctl_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, slpc_param_ctl_show, inode->i_private);
+}
+
+static const char *read_token = "read", *write_token = "write",
+ *revert_token = "revert";
+
+/*
+ * Parse SLPC parameter control strings: (Similar to Pipe CRC handling)
+ * command: wsp* op wsp+ param id wsp+ [value] wsp*
+ * op: "read"/"write"/"revert"
+ * param id: slpc_param_id
+ * value: u32 value
+ * wsp: (#0x20 | #0x9 | #0xA)+
+ *
+ * eg.:
+ * "read 0" -> read SLPC_PARAM_TASK_ENABLE_GTPERF
+ * "write 7 500" -> set SLPC_PARAM_GLOBAL_MIN_GT_SLICE_FREQ_MHZ to 500MHz
+ * "revert 7" -> revert SLPC_PARAM_GLOBAL_MIN_GT_SLICE_FREQ_MHZ to
+ * default value.
+ */
+static int slpc_param_ctl_parse(char *buf, size_t len, char **op,
+ u32 *id, u32 *value)
+{
+#define MAX_WORDS 3
+ int n_words;
+ char *words[MAX_WORDS];
+ ssize_t ret;
+
+ n_words = buffer_tokenize(buf, words, MAX_WORDS);
+ if (!(n_words == 3) && !(n_words == 2)) {
+ DRM_DEBUG_DRIVER("tokenize failed, a command is %d words\n",
+ MAX_WORDS);
+ return -EINVAL;
+ }
+
+ if (strcmp(words[0], read_token) && strcmp(words[0], write_token) &&
+ strcmp(words[0], revert_token)) {
+ DRM_DEBUG_DRIVER("unknown operation\n");
+ return -EINVAL;
+ }
+
+ *op = words[0];
+
+ ret = kstrtou32(words[1], 0, id);
+ if (ret)
+ return ret;
+
+ if (n_words == 3) {
+ ret = kstrtou32(words[2], 0, value);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static ssize_t slpc_param_ctl_write(struct file *file, const char __user *ubuf,
+ size_t len, loff_t *offp)
+{
+ struct seq_file *m = file->private_data;
+ struct drm_i915_private *dev_priv = m->private;
+ struct intel_slpc *slpc = &dev_priv->guc.slpc;
+ char *tmpbuf, *op = NULL;
+ u32 id, value;
+ int ret;
+
+ if (len == 0)
+ return 0;
+
+ if (len > 40) {
+ DRM_DEBUG_DRIVER("expected <40 chars into slpc_param_ctl\n");
+ return -E2BIG;
+ }
+
+ tmpbuf = kmalloc(len + 1, GFP_KERNEL);
+ if (!tmpbuf)
+ return -ENOMEM;
+
+ if (copy_from_user(tmpbuf, ubuf, len)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ tmpbuf[len] = '\0';
+
+ ret = slpc_param_ctl_parse(tmpbuf, len, &op, &id, &value);
+
+ if (id >= SLPC_MAX_PARAM) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (!strcmp(op, read_token)) {
+ intel_slpc_get_param(slpc, id,
+ &slpc->debug_param_override,
+ &slpc->debug_param_value);
+ slpc->debug_param_id = id;
+ } else if (!strcmp(op, write_token) || !strcmp(op, revert_token)) {
+ if ((id >= SLPC_PARAM_TASK_ENABLE_GTPERF) &&
+ (id <= SLPC_PARAM_TASK_DISABLE_DCC)) {
+ DRM_DEBUG_DRIVER("Tasks are not controlled by "
+ "this interface\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * After updating parameters, RESET event has to be sent to GuC
+ * SLPC for ensuring parameters take effect.
+ */
+ intel_runtime_pm_get(dev_priv);
+ if (!strcmp(op, write_token))
+ intel_slpc_set_param(slpc, id, value);
+ else if (!strcmp(op, revert_token))
+ intel_slpc_unset_param(slpc, id);
+ intel_slpc_enable(slpc);
+ intel_runtime_pm_put(dev_priv);
+ }
+
+out:
+ kfree(tmpbuf);
+ if (ret < 0)
+ return ret;
+
+ *offp += len;
+ return len;
+}
+
+const struct file_operations i915_slpc_param_ctl_fops = {
+ .owner = THIS_MODULE,
+ .open = slpc_param_ctl_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+ .write = slpc_param_ctl_write
+};
diff --git a/drivers/gpu/drm/i915/intel_slpc.h b/drivers/gpu/drm/i915/intel_slpc.h
index ae857d3..e49c513 100644
--- a/drivers/gpu/drm/i915/intel_slpc.h
+++ b/drivers/gpu/drm/i915/intel_slpc.h
@@ -32,6 +32,10 @@ struct intel_slpc {
/* i915 cached SLPC frequency limits */
u32 min_unslice_freq;
u32 max_unslice_freq;
+
+ u32 debug_param_id;
+ u32 debug_param_value;
+ u32 debug_param_override;
};

static inline int intel_slpc_enabled(void)
@@ -251,6 +255,8 @@ struct slpc_param {
#define SLPC_PARAM_TASK_DISABLED 2
#define SLPC_PARAM_TASK_UNKNOWN 3

+extern const struct file_operations i915_slpc_param_ctl_fops;
+
/* intel_slpc.c */
void intel_slpc_set_param(struct intel_slpc *slpc, u32 id, u32 value);
void intel_slpc_unset_param(struct intel_slpc *slpc, u32 id);