[Intel-xe] [PATCH v2 2/3] drm/xe: Allow userspace to configure CCS mode

[Niranjana Vishwanathapura]

Allow user to configure the CCS mode setting through a
'ccs_mode' sysfs interface. Also report the current
CCS mode configuration and number of compute slices
available through this interface.

v2: Rebase, make it platform agnostic

Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
---
 drivers/gpu/drm/xe/xe_gt.c          |  6 +++
 drivers/gpu/drm/xe/xe_gt_ccs_mode.c | 74 +++++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_gt_ccs_mode.h |  1 +
 3 files changed, 81 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
index 1e534dd7e2a8..2622e6ea7f57 100644
--- a/drivers/gpu/drm/xe/xe_gt.c
+++ b/drivers/gpu/drm/xe/xe_gt.c
@@ -380,6 +380,12 @@ static int gt_fw_domain_init(struct xe_gt *gt)
 			 "failed to register engines sysfs directory, err: %d\n",
 			 err);
 
+	err = xe_gt_ccs_mode_sysfs_init(gt);
+	if (err)
+		drm_warn(&gt_to_xe(gt)->drm,
+			 "Sysfs creation for ccs_mode setting failed err: %d\n",
+			 err);
+
 	err = xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
 	XE_WARN_ON(err);
 	xe_device_mem_access_put(gt_to_xe(gt));
diff --git a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
index 8441316bb35c..0ad97383aedd 100644
--- a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
+++ b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
@@ -3,10 +3,13 @@
  * Copyright © 2023 Intel Corporation
  */
 
+#include <drm/drm_managed.h>
+
 #include "regs/xe_gt_regs.h"
 #include "xe_assert.h"
 #include "xe_gt.h"
 #include "xe_gt_ccs_mode.h"
+#include "xe_gt_sysfs.h"
 #include "xe_mmio.h"
 
 static void __xe_gt_apply_ccs_mode(struct xe_gt *gt, u32 num_engines)
@@ -71,3 +74,74 @@ void xe_gt_apply_ccs_mode(struct xe_gt *gt)
 	if (gt->ccs_mode.num_engines)
 		__xe_gt_apply_ccs_mode(gt, gt->ccs_mode.num_engines);
 }
+
+static ssize_t
+ccs_mode_show(struct device *kdev,
+	      struct device_attribute *attr, char *buf)
+{
+	struct xe_gt *gt = kobj_to_gt(&kdev->kobj);
+
+	return sysfs_emit(buf, "Enabled compute engines %d; Number of compute slices %d\n",
+			  gt->ccs_mode.num_engines, hweight32(CCS_MASK(gt)));
+}
+
+static ssize_t
+ccs_mode_store(struct device *kdev, struct device_attribute *attr,
+	       const char *buff, size_t count)
+{
+	struct xe_gt *gt = kobj_to_gt(&kdev->kobj);
+	u32 num_engines, num_slices;
+	int ret;
+
+	ret = kstrtou32(buff, 0, &num_engines);
+	if (ret)
+		return ret;
+
+	/*
+	 * Ensure number of engines specified is valid and there is an
+	 * exact multiple of engines for slices.
+	 */
+	num_slices = hweight32(CCS_MASK(gt));
+	if (!num_engines || num_engines > num_slices || num_slices % num_engines) {
+		xe_gt_dbg(gt, "Invalid compute config, %d engines %d slices\n",
+			  num_engines, num_slices);
+		return -EINVAL;
+	}
+
+	if (gt->ccs_mode.num_engines != num_engines) {
+		xe_gt_info(gt, "Setting compute mode to %d\n", num_engines);
+		gt->ccs_mode.num_engines = num_engines;
+		xe_gt_reset_async(gt);
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(ccs_mode);
+
+static void xe_gt_ccs_mode_sysfs_fini(struct drm_device *drm, void *arg)
+{
+	struct xe_gt *gt = arg;
+
+	sysfs_remove_file(gt->sysfs, &dev_attr_ccs_mode.attr);
+}
+
+int xe_gt_ccs_mode_sysfs_init(struct xe_gt *gt)
+{
+	struct xe_device *xe = gt_to_xe(gt);
+	int err;
+
+	if (!xe_gt_ccs_mode_enabled(gt))
+		return 0;
+
+	err = sysfs_create_file(gt->sysfs, &dev_attr_ccs_mode.attr);
+	if (err)
+		return err;
+
+	err = drmm_add_action_or_reset(&xe->drm, xe_gt_ccs_mode_sysfs_fini, gt);
+	if (err)
+		drm_warn(&xe->drm, "%s: drmm_add_action_or_reset failed, err: %d\n",
+			 __func__, err);
+
+	return err;
+}
diff --git a/drivers/gpu/drm/xe/xe_gt_ccs_mode.h b/drivers/gpu/drm/xe/xe_gt_ccs_mode.h
index 9aa6223ca83b..d09e2f9ae50a 100644
--- a/drivers/gpu/drm/xe/xe_gt_ccs_mode.h
+++ b/drivers/gpu/drm/xe/xe_gt_ccs_mode.h
@@ -12,6 +12,7 @@
 #include "xe_platform_types.h"
 
 void xe_gt_apply_ccs_mode(struct xe_gt *gt);
+int xe_gt_ccs_mode_sysfs_init(struct xe_gt *gt);
 
 static inline bool xe_gt_ccs_mode_enabled(const struct xe_gt *gt)
 {
-- 
2.21.0.rc0.32.g243a4c7e27