GMBUS HW supports 511Bytes as Max Bytes per single RD/WR op. Instead of
enabling the 511Bytes per RD/WR cycle on legacy platforms for no
absolute ROIs, this change allows the max bytes per op upto 511Bytes
from Gen9 onwards.
v2:
No Change.
v3:
Inline function for max_xfer_size and renaming of the macro.[Jani]
v4:
Extra brackets removed [ville]
Commit msg is modified.
v5:
Adding the Reviewed-By received.
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx>
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_reg.h | 1 +
drivers/gpu/drm/i915/intel_i2c.c | 11 +++++++++--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 8a0da35718aa..ebdf7c9d816e 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3025,6 +3025,7 @@ enum i915_power_well_id {
#define GMBUS_CYCLE_STOP (4<<25)
#define GMBUS_BYTE_COUNT_SHIFT 16
#define GMBUS_BYTE_COUNT_MAX 256U
+#define GEN9_GMBUS_BYTE_COUNT_MAX 511U
#define GMBUS_SLAVE_INDEX_SHIFT 8
#define GMBUS_SLAVE_ADDR_SHIFT 1
#define GMBUS_SLAVE_READ (1<<0)
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index e6875509bcd9..1c0f6b56b209 100644
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -361,6 +361,13 @@ gmbus_wait_idle(struct drm_i915_private *dev_priv)
return ret;
}
+static inline
+unsigned int gmbus_max_xfer_size(struct drm_i915_private *dev_priv)
+{
+ return INTEL_GEN(dev_priv) >= 9 ? GEN9_GMBUS_BYTE_COUNT_MAX :
+ GMBUS_BYTE_COUNT_MAX;
+}
+
static int
gmbus_xfer_read_chunk(struct drm_i915_private *dev_priv,
unsigned short addr, u8 *buf, unsigned int len,
@@ -400,7 +407,7 @@ gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
int ret;
do {
- len = min(rx_size, GMBUS_BYTE_COUNT_MAX);
+ len = min(rx_size, gmbus_max_xfer_size(dev_priv));
ret = gmbus_xfer_read_chunk(dev_priv, msg->addr,
buf, len, gmbus1_index);
@@ -462,7 +469,7 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
int ret;
do {
- len = min(tx_size, GMBUS_BYTE_COUNT_MAX);
+ len = min(tx_size, gmbus_max_xfer_size(dev_priv));
ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len,
gmbus1_index);
--
2.7.4
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