drm/i915/params: add i915 parameters to debugfs

Add a debugfs subdirectory i915_params with all the i915 module
parameters. This is a first step, with lots of boilerplate, and not much
benefit yet.

This will result in a new device specific debugfs directory at
/sys/kernel/debug/dri/<N>/i915_params duplicating the module specific
sysfs directory at /sys/module/i915/parameters/. Going forward, all
users of the parameters should use the debugfs, with the module
parameters being phased out.

Add debugfs permissions to I915_PARAMS_FOR_EACH(). This duplicates the
mode with module parameter sysfs, but the goal is to make the module
parameters read-only initial values for device specific parameters.

0 mode will bypass debugfs creation. Use it for verbose_state_checks
which will need special attention in follow-up work.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/600101c8433e7caf9303663fc85a9972fa1f05e7.1575560168.git.jani.nikula@intel.com

1 files changed, 39 insertions, 37 deletions

diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index 31b88f297fbc..be6089e4f9e6 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -36,49 +36,51 @@ struct drm_printer;
 /*
  * Invoke param, a function-like macro, for each i915 param, with arguments:
  *
- * param(type, name, value)
+ * param(type, name, value, mode)
  *
- * type: parameter type, one of {bool, int, unsigned int, char *}
+ * type: parameter type, one of {bool, int, unsigned int, unsigned long, char *}
  * name: name of the parameter
  * value: initial/default value of the parameter
+ * mode: debugfs file permissions, one of {0400, 0600, 0}, use 0 to not create
+ *       debugfs file
  */
 #define I915_PARAMS_FOR_EACH(param) \
-	param(char *, vbt_firmware, NULL) \
-	param(int, modeset, -1) \
-	param(int, lvds_channel_mode, 0) \
-	param(int, panel_use_ssc, -1) \
-	param(int, vbt_sdvo_panel_type, -1) \
-	param(int, enable_dc, -1) \
-	param(int, enable_fbc, -1) \
-	param(int, enable_psr, -1) \
-	param(int, disable_power_well, -1) \
-	param(int, enable_ips, 1) \
-	param(int, invert_brightness, 0) \
-	param(int, enable_guc, 0) \
-	param(int, guc_log_level, -1) \
-	param(char *, guc_firmware_path, NULL) \
-	param(char *, huc_firmware_path, NULL) \
-	param(char *, dmc_firmware_path, NULL) \
-	param(int, mmio_debug, -IS_ENABLED(CONFIG_DRM_I915_DEBUG_MMIO)) \
-	param(int, edp_vswing, 0) \
-	param(int, reset, 3) \
-	param(unsigned int, inject_probe_failure, 0) \
-	param(int, fastboot, -1) \
-	param(int, enable_dpcd_backlight, 0) \
-	param(char *, force_probe, CONFIG_DRM_I915_FORCE_PROBE) \
-	param(unsigned long, fake_lmem_start, 0) \
+	param(char *, vbt_firmware, NULL, 0400) \
+	param(int, modeset, -1, 0400) \
+	param(int, lvds_channel_mode, 0, 0400) \
+	param(int, panel_use_ssc, -1, 0600) \
+	param(int, vbt_sdvo_panel_type, -1, 0400) \
+	param(int, enable_dc, -1, 0400) \
+	param(int, enable_fbc, -1, 0600) \
+	param(int, enable_psr, -1, 0600) \
+	param(int, disable_power_well, -1, 0400) \
+	param(int, enable_ips, 1, 0600) \
+	param(int, invert_brightness, 0, 0600) \
+	param(int, enable_guc, 0, 0400) \
+	param(int, guc_log_level, -1, 0400) \
+	param(char *, guc_firmware_path, NULL, 0400) \
+	param(char *, huc_firmware_path, NULL, 0400) \
+	param(char *, dmc_firmware_path, NULL, 0400) \
+	param(int, mmio_debug, -IS_ENABLED(CONFIG_DRM_I915_DEBUG_MMIO), 0600) \
+	param(int, edp_vswing, 0, 0400) \
+	param(int, reset, 3, 0600) \
+	param(unsigned int, inject_probe_failure, 0, 0600) \
+	param(int, fastboot, -1, 0600) \
+	param(int, enable_dpcd_backlight, 0, 0600) \
+	param(char *, force_probe, CONFIG_DRM_I915_FORCE_PROBE, 0400) \
+	param(unsigned long, fake_lmem_start, 0, 0400) \
 	/* leave bools at the end to not create holes */ \
-	param(bool, alpha_support, IS_ENABLED(CONFIG_DRM_I915_ALPHA_SUPPORT)) \
-	param(bool, enable_hangcheck, true) \
-	param(bool, prefault_disable, false) \
-	param(bool, load_detect_test, false) \
-	param(bool, force_reset_modeset_test, false) \
-	param(bool, error_capture, true) \
-	param(bool, disable_display, false) \
-	param(bool, verbose_state_checks, true) \
-	param(bool, nuclear_pageflip, false) \
-	param(bool, enable_dp_mst, true) \
-	param(bool, enable_gvt, false)
+	param(bool, alpha_support, IS_ENABLED(CONFIG_DRM_I915_ALPHA_SUPPORT), 0400) \
+	param(bool, enable_hangcheck, true, 0600) \
+	param(bool, prefault_disable, false, 0600) \
+	param(bool, load_detect_test, false, 0600) \
+	param(bool, force_reset_modeset_test, false, 0600) \
+	param(bool, error_capture, true, 0600) \
+	param(bool, disable_display, false, 0400) \
+	param(bool, verbose_state_checks, true, 0) \
+	param(bool, nuclear_pageflip, false, 0400) \
+	param(bool, enable_dp_mst, true, 0600) \
+	param(bool, enable_gvt, false, 0400)
 
 #define MEMBER(T, member, ...) T member;
 struct i915_params {