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drm/i915: proper use of forcewake
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Moved the macros around to properly do reads and writes for the given
GPU. This is to address special requirements for gen6 (SNB) reads and
writes.

Registers in the range 0-0x40000 on gen6 platforms require special
handling. Instead of relying on the callers to pick the registers
correctly, move the logic into the read and write functions.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
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Ben Widawsky authored and Keith Packard committed May 10, 2011
1 parent 2c7111d commit b7287d8
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Showing 2 changed files with 37 additions and 46 deletions.
54 changes: 24 additions & 30 deletions drivers/gpu/drm/i915/i915_drv.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1325,10 +1325,30 @@ extern void intel_display_print_error_state(struct seq_file *m,
LOCK_TEST_WITH_RETURN(dev, file); \
} while (0)

/* On SNB platform, before reading ring registers forcewake bit
* must be set to prevent GT core from power down and stale values being
* returned.
*/
void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv);
void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv);
void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv);

/* We give fast paths for the really cool registers */
#define NEEDS_FORCE_WAKE(dev_priv, reg) \
(((dev_priv)->info->gen >= 6) && \
((reg) < 0x40000) && \
((reg) != FORCEWAKE))

#define __i915_read(x, y) \
static inline u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
u##x val = read##y(dev_priv->regs + reg); \
u##x val = 0; \
if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
__gen6_gt_force_wake_get(dev_priv); \
val = read##y(dev_priv->regs + reg); \
__gen6_gt_force_wake_put(dev_priv); \
} else { \
val = read##y(dev_priv->regs + reg); \
} \
trace_i915_reg_rw(false, reg, val, sizeof(val)); \
return val; \
}
Expand All @@ -1341,6 +1361,9 @@ __i915_read(64, q)
#define __i915_write(x, y) \
static inline void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
trace_i915_reg_rw(true, reg, val, sizeof(val)); \
if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
__gen6_gt_wait_for_fifo(dev_priv); \
} \
write##y(val, dev_priv->regs + reg); \
}
__i915_write(8, b)
Expand Down Expand Up @@ -1369,33 +1392,4 @@ __i915_write(64, q)
#define POSTING_READ16(reg) (void)I915_READ16_NOTRACE(reg)


/* On SNB platform, before reading ring registers forcewake bit
* must be set to prevent GT core from power down and stale values being
* returned.
*/
void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv);
void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv);
void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv);

static inline u32 i915_gt_read(struct drm_i915_private *dev_priv, u32 reg)
{
u32 val;

if (dev_priv->info->gen >= 6) {
__gen6_gt_force_wake_get(dev_priv);
val = I915_READ(reg);
__gen6_gt_force_wake_put(dev_priv);
} else
val = I915_READ(reg);

return val;
}

static inline void i915_gt_write(struct drm_i915_private *dev_priv,
u32 reg, u32 val)
{
if (dev_priv->info->gen >= 6)
__gen6_gt_wait_for_fifo(dev_priv);
I915_WRITE(reg, val);
}
#endif
29 changes: 13 additions & 16 deletions drivers/gpu/drm/i915/intel_ringbuffer.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,27 +14,24 @@ struct intel_hw_status_page {
struct drm_i915_gem_object *obj;
};

#define I915_RING_READ(reg) i915_gt_read(dev_priv, reg)
#define I915_RING_WRITE(reg, val) i915_gt_write(dev_priv, reg, val)
#define I915_READ_TAIL(ring) I915_READ(RING_TAIL((ring)->mmio_base))
#define I915_WRITE_TAIL(ring, val) I915_WRITE(RING_TAIL((ring)->mmio_base), val)

#define I915_READ_TAIL(ring) I915_RING_READ(RING_TAIL((ring)->mmio_base))
#define I915_WRITE_TAIL(ring, val) I915_RING_WRITE(RING_TAIL((ring)->mmio_base), val)
#define I915_READ_START(ring) I915_READ(RING_START((ring)->mmio_base))
#define I915_WRITE_START(ring, val) I915_WRITE(RING_START((ring)->mmio_base), val)

#define I915_READ_START(ring) I915_RING_READ(RING_START((ring)->mmio_base))
#define I915_WRITE_START(ring, val) I915_RING_WRITE(RING_START((ring)->mmio_base), val)
#define I915_READ_HEAD(ring) I915_READ(RING_HEAD((ring)->mmio_base))
#define I915_WRITE_HEAD(ring, val) I915_WRITE(RING_HEAD((ring)->mmio_base), val)

#define I915_READ_HEAD(ring) I915_RING_READ(RING_HEAD((ring)->mmio_base))
#define I915_WRITE_HEAD(ring, val) I915_RING_WRITE(RING_HEAD((ring)->mmio_base), val)
#define I915_READ_CTL(ring) I915_READ(RING_CTL((ring)->mmio_base))
#define I915_WRITE_CTL(ring, val) I915_WRITE(RING_CTL((ring)->mmio_base), val)

#define I915_READ_CTL(ring) I915_RING_READ(RING_CTL((ring)->mmio_base))
#define I915_WRITE_CTL(ring, val) I915_RING_WRITE(RING_CTL((ring)->mmio_base), val)
#define I915_READ_IMR(ring) I915_READ(RING_IMR((ring)->mmio_base))
#define I915_WRITE_IMR(ring, val) I915_WRITE(RING_IMR((ring)->mmio_base), val)

#define I915_READ_IMR(ring) I915_RING_READ(RING_IMR((ring)->mmio_base))
#define I915_WRITE_IMR(ring, val) I915_RING_WRITE(RING_IMR((ring)->mmio_base), val)

#define I915_READ_NOPID(ring) I915_RING_READ(RING_NOPID((ring)->mmio_base))
#define I915_READ_SYNC_0(ring) I915_RING_READ(RING_SYNC_0((ring)->mmio_base))
#define I915_READ_SYNC_1(ring) I915_RING_READ(RING_SYNC_1((ring)->mmio_base))
#define I915_READ_NOPID(ring) I915_READ(RING_NOPID((ring)->mmio_base))
#define I915_READ_SYNC_0(ring) I915_READ(RING_SYNC_0((ring)->mmio_base))
#define I915_READ_SYNC_1(ring) I915_READ(RING_SYNC_1((ring)->mmio_base))

struct intel_ring_buffer {
const char *name;
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