[Intel-xe] [PATCH 2/3] drm/xe/pvc: 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.

Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
---
 drivers/gpu/drm/xe/xe_gt_sysfs.c | 53 ++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_gt_sysfs.c b/drivers/gpu/drm/xe/xe_gt_sysfs.c
index c69d2e8a0fe1..36f7bd34bc78 100644
--- a/drivers/gpu/drm/xe/xe_gt_sysfs.c
+++ b/drivers/gpu/drm/xe/xe_gt_sysfs.c
@@ -10,7 +10,11 @@
 
 #include <drm/drm_managed.h>
 
+#include "regs/xe_gt_regs.h"
 #include "xe_gt.h"
+#include "xe_gt_ccs_mode.h"
+#include "xe_gt_printk.h"
+#include "xe_mmio.h"
 
 static void xe_gt_sysfs_kobj_release(struct kobject *kobj)
 {
@@ -29,6 +33,50 @@ static void gt_sysfs_fini(struct drm_device *drm, void *arg)
 	kobject_put(gt->sysfs);
 }
 
+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);
+
 void xe_gt_sysfs_init(struct xe_gt *gt)
 {
 	struct xe_tile *tile = gt_to_tile(gt);
@@ -52,6 +100,11 @@ void xe_gt_sysfs_init(struct xe_gt *gt)
 
 	gt->sysfs = &kg->base;
 
+	if (GRAPHICS_VERx100(xe) == 1260 &&
+	    sysfs_create_file(gt->sysfs, &dev_attr_ccs_mode.attr))
+		drm_warn(&xe->drm,
+			 "Sysfs creation for ccs_mode setting failed\n");
+
 	err = drmm_add_action_or_reset(&xe->drm, gt_sysfs_fini, gt);
 	if (err) {
 		drm_warn(&xe->drm, "%s: drmm_add_action_or_reset failed, err: %d\n",
-- 
2.21.0.rc0.32.g243a4c7e27