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Commit 73675cf6 authored by Ramalingam C's avatar Ramalingam C Committed by Daniel Vetter
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drm/i915/gmbus: Increase the Bytes per Rd/Wr Op 



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:
  Collecting the Reviewed-By received.

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarRamalingam C <ramalingam.c@intel.com>
Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1530192889-5789-2-git-send-email-ramalingam.c@intel.com
parent a63983f2

drivers/gpu/drm/i915/i915_reg.h

+1 −0
Original line number Diff line number Diff line
@@ -3152,6 +3152,7 @@ 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)

drivers/gpu/drm/i915/intel_i2c.c

+9 −2
Original line number Diff line number Diff line
@@ -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);