drm/xe/mmio: Use single logic for waiting functions

The implementations for xe_mmio_wait32() and xe_mmio_wait32_not() are
almost identical. Let us avoid duplication of logic by having them
calling a common __xe_mmio_wait32() function.

Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240723120120.5443-2-gustavo.sousa@intel.com

diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
index 435c01d003a85e1a1a869652324508ee4ec0592c..bdcc7282385c4e27986b5284c4091c24f9468f9d 100644 (file)
--- a/drivers/gpu/drm/xe/xe_mmio.c
+++ b/drivers/gpu/drm/xe/xe_mmio.c
@@ -333,37 +333,24 @@ u64 xe_mmio_read64_2x32(struct xe_gt *gt, struct xe_reg reg)
        return (u64)udw << 32 | ldw;
 }
 
-/**
- * xe_mmio_wait32() - Wait for a register to match the desired masked value
- * @gt: MMIO target GT
- * @reg: register to read value from
- * @mask: mask to be applied to the value read from the register
- * @val: desired value after applying the mask
- * @timeout_us: time out after this period of time. Wait logic tries to be
- * smart, applying an exponential backoff until @timeout_us is reached.
- * @out_val: if not NULL, points where to store the last unmasked value
- * @atomic: needs to be true if calling from an atomic context
- *
- * This function polls for the desired masked value and returns zero on success
- * or -ETIMEDOUT if timed out.
- *
- * Note that @timeout_us represents the minimum amount of time to wait before
- * giving up. The actual time taken by this function can be a little more than
- * @timeout_us for different reasons, specially in non-atomic contexts. Thus,
- * it is possible that this function succeeds even after @timeout_us has passed.
- */
-int xe_mmio_wait32(struct xe_gt *gt, struct xe_reg reg, u32 mask, u32 val, u32 timeout_us,
-                  u32 *out_val, bool atomic)
+static int __xe_mmio_wait32(struct xe_gt *gt, struct xe_reg reg, u32 mask, u32 val, u32 timeout_us,
+                           u32 *out_val, bool atomic, bool expect_match)
 {
        ktime_t cur = ktime_get_raw();
        const ktime_t end = ktime_add_us(cur, timeout_us);
        int ret = -ETIMEDOUT;
        s64 wait = 10;
        u32 read;
+       bool check;
 
        for (;;) {
                read = xe_mmio_read32(gt, reg);
-               if ((read & mask) == val) {
+
+               check = (read & mask) == val;
+               if (!expect_match)
+                       check = !check;
+
+               if (check) {
                        ret = 0;
                        break;
                }
@@ -384,7 +371,12 @@ int xe_mmio_wait32(struct xe_gt *gt, struct xe_reg reg, u32 mask, u32 val, u32 t
 
        if (ret != 0) {
                read = xe_mmio_read32(gt, reg);
-               if ((read & mask) == val)
+
+               check = (read & mask) == val;
+               if (!expect_match)
+                       check = !check;
+
+               if (check)
                        ret = 0;
        }
 
@@ -395,62 +387,45 @@ int xe_mmio_wait32(struct xe_gt *gt, struct xe_reg reg, u32 mask, u32 val, u32 t
 }
 
 /**
- * xe_mmio_wait32_not() - Wait for a register to return anything other than the given masked value
+ * xe_mmio_wait32() - Wait for a register to match the desired masked value
  * @gt: MMIO target GT
  * @reg: register to read value from
  * @mask: mask to be applied to the value read from the register
- * @val: value to match after applying the mask
+ * @val: desired value after applying the mask
  * @timeout_us: time out after this period of time. Wait logic tries to be
  * smart, applying an exponential backoff until @timeout_us is reached.
  * @out_val: if not NULL, points where to store the last unmasked value
  * @atomic: needs to be true if calling from an atomic context
  *
- * This function polls for a masked value to change from a given value and
- * returns zero on success or -ETIMEDOUT if timed out.
+ * This function polls for the desired masked value and returns zero on success
+ * or -ETIMEDOUT if timed out.
  *
  * Note that @timeout_us represents the minimum amount of time to wait before
  * giving up. The actual time taken by this function can be a little more than
  * @timeout_us for different reasons, specially in non-atomic contexts. Thus,
  * it is possible that this function succeeds even after @timeout_us has passed.
  */
+int xe_mmio_wait32(struct xe_gt *gt, struct xe_reg reg, u32 mask, u32 val, u32 timeout_us,
+                  u32 *out_val, bool atomic)
+{
+       return __xe_mmio_wait32(gt, reg, mask, val, timeout_us, out_val, atomic, true);
+}
+
+/**
+ * xe_mmio_wait32_not() - Wait for a register to return anything other than the given masked value
+ * @gt: MMIO target GT
+ * @reg: register to read value from
+ * @mask: mask to be applied to the value read from the register
+ * @val: value not to be matched after applying the mask
+ * @timeout_us: time out after this period of time
+ * @out_val: if not NULL, points where to store the last unmasked value
+ * @atomic: needs to be true if calling from an atomic context
+ *
+ * This function works exactly like xe_mmio_wait32() with the exception that
+ * @val is expected not to be matched.
+ */
 int xe_mmio_wait32_not(struct xe_gt *gt, struct xe_reg reg, u32 mask, u32 val, u32 timeout_us,
                       u32 *out_val, bool atomic)
 {
-       ktime_t cur = ktime_get_raw();
-       const ktime_t end = ktime_add_us(cur, timeout_us);
-       int ret = -ETIMEDOUT;
-       s64 wait = 10;
-       u32 read;
-
-       for (;;) {
-               read = xe_mmio_read32(gt, reg);
-               if ((read & mask) != val) {
-                       ret = 0;
-                       break;
-               }
-
-               cur = ktime_get_raw();
-               if (!ktime_before(cur, end))
-                       break;
-
-               if (ktime_after(ktime_add_us(cur, wait), end))
-                       wait = ktime_us_delta(end, cur);
-
-               if (atomic)
-                       udelay(wait);
-               else
-                       usleep_range(wait, wait << 1);
-               wait <<= 1;
-       }
-
-       if (ret != 0) {
-               read = xe_mmio_read32(gt, reg);
-               if ((read & mask) != val)
-                       ret = 0;
-       }
-
-       if (out_val)
-               *out_val = read;
-
-       return ret;
+       return __xe_mmio_wait32(gt, reg, mask, val, timeout_us, out_val, atomic, false);
 }