Re: [PATCH] drm/radeon: add a i2c bus mutex

Christian König <deathsimple@xxxxxxxxxxx> · Mon, 12 May 2014 15:24:20 +0200

Am 08.05.2014 16:58, schrieb Alex Deucher:
The i2c and aux buses use the same pads so add
a mutex to protect access to the pads.

Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>

I've applied this one, "drm/radeon: fix DCE83 check for mullins" and 
"drm/radeon: handle non-VGA class pci devices with ATRM" my 3.15 queue.

Thanks,
Christian.

---
  drivers/gpu/drm/radeon/atombios_dp.c  | 18 ++++++++++++++----
  drivers/gpu/drm/radeon/atombios_i2c.c | 17 +++++++++++++----
  drivers/gpu/drm/radeon/radeon_i2c.c   |  9 +++++++++
  drivers/gpu/drm/radeon/radeon_mode.h  |  1 +
  4 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 54e4f52..3bb0933 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -95,9 +95,12 @@ static int radeon_process_aux_ch(struct radeon_i2c_chan *chan,
  	int index = GetIndexIntoMasterTable(COMMAND, ProcessAuxChannelTransaction);
  	unsigned char *base;
  	int recv_bytes;
+	int r = 0;
  
  	memset(&args, 0, sizeof(args));
  
+	mutex_lock(&chan->mutex);
+
  	base = (unsigned char *)(rdev->mode_info.atom_context->scratch + 1);
  
  	radeon_atom_copy_swap(base, send, send_bytes, true);
@@ -117,19 +120,22 @@ static int radeon_process_aux_ch(struct radeon_i2c_chan *chan,
  	/* timeout */
  	if (args.v1.ucReplyStatus == 1) {
  		DRM_DEBUG_KMS("dp_aux_ch timeout\n");
-		return -ETIMEDOUT;
+		r = -ETIMEDOUT;
+		goto done;
  	}
  
  	/* flags not zero */
  	if (args.v1.ucReplyStatus == 2) {
  		DRM_DEBUG_KMS("dp_aux_ch flags not zero\n");
-		return -EBUSY;
+		r = -EBUSY;
+		goto done;
  	}
  
  	/* error */
  	if (args.v1.ucReplyStatus == 3) {
  		DRM_DEBUG_KMS("dp_aux_ch error\n");
-		return -EIO;
+		r = -EIO;
+		goto done;
  	}
  
  	recv_bytes = args.v1.ucDataOutLen;
@@ -139,7 +145,11 @@ static int radeon_process_aux_ch(struct radeon_i2c_chan *chan,
  	if (recv && recv_size)
  		radeon_atom_copy_swap(recv, base + 16, recv_bytes, false);
  
-	return recv_bytes;
+	r = recv_bytes;
+done:
+	mutex_unlock(&chan->mutex);
+
+	return r;
  }
  
  #define BARE_ADDRESS_SIZE 3
diff --git a/drivers/gpu/drm/radeon/atombios_i2c.c b/drivers/gpu/drm/radeon/atombios_i2c.c
index b5162c3..9c570fb 100644
--- a/drivers/gpu/drm/radeon/atombios_i2c.c
+++ b/drivers/gpu/drm/radeon/atombios_i2c.c
@@ -43,15 +43,19 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
  	int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
  	unsigned char *base;
  	u16 out = cpu_to_le16(0);
+	int r = 0;
  
  	memset(&args, 0, sizeof(args));
  
+	mutex_lock(&chan->mutex);
+
  	base = (unsigned char *)rdev->mode_info.atom_context->scratch;
  
  	if (flags & HW_I2C_WRITE) {
  		if (num > ATOM_MAX_HW_I2C_WRITE) {
  			DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 3)\n", num);
-			return -EINVAL;
+			r = -EINVAL;
+			goto done;
  		}
  		if (buf == NULL)
  			args.ucRegIndex = 0;
@@ -65,7 +69,8 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
  	} else {
  		if (num > ATOM_MAX_HW_I2C_READ) {
  			DRM_ERROR("hw i2c: tried to read too many bytes (%d vs 255)\n", num);
-			return -EINVAL;
+			r = -EINVAL;
+			goto done;
  		}
  		args.ucRegIndex = 0;
  		args.lpI2CDataOut = 0;
@@ -82,13 +87,17 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
  	/* error */
  	if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
  		DRM_DEBUG_KMS("hw_i2c error\n");
-		return -EIO;
+		r = -EIO;
+		goto done;
  	}
  
  	if (!(flags & HW_I2C_WRITE))
  		radeon_atom_copy_swap(buf, base, num, false);
  
-	return 0;
+done:
+	mutex_unlock(&chan->mutex);
+
+	return r;
  }
  
  int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c
index 7b94414..427ee4d 100644
--- a/drivers/gpu/drm/radeon/radeon_i2c.c
+++ b/drivers/gpu/drm/radeon/radeon_i2c.c
@@ -94,6 +94,8 @@ static int pre_xfer(struct i2c_adapter *i2c_adap)
  	struct radeon_i2c_bus_rec *rec = &i2c->rec;
  	uint32_t temp;
  
+	mutex_lock(&i2c->mutex);
+
  	/* RV410 appears to have a bug where the hw i2c in reset
  	 * holds the i2c port in a bad state - switch hw i2c away before
  	 * doing DDC - do this for all r200s/r300s/r400s for safety sake
@@ -170,6 +172,8 @@ static void post_xfer(struct i2c_adapter *i2c_adap)
  	temp = RREG32(rec->mask_data_reg) & ~rec->mask_data_mask;
  	WREG32(rec->mask_data_reg, temp);
  	temp = RREG32(rec->mask_data_reg);
+
+	mutex_unlock(&i2c->mutex);
  }
  
  static int get_clock(void *i2c_priv)
@@ -813,6 +817,8 @@ static int radeon_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
  	struct radeon_i2c_bus_rec *rec = &i2c->rec;
  	int ret = 0;
  
+	mutex_lock(&i2c->mutex);
+
  	switch (rdev->family) {
  	case CHIP_R100:
  	case CHIP_RV100:
@@ -879,6 +885,8 @@ static int radeon_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
  		break;
  	}
  
+	mutex_unlock(&i2c->mutex);
+
  	return ret;
  }
  
@@ -919,6 +927,7 @@ struct radeon_i2c_chan *radeon_i2c_create(struct drm_device *dev,
  	i2c->adapter.dev.parent = &dev->pdev->dev;
  	i2c->dev = dev;
  	i2c_set_adapdata(&i2c->adapter, i2c);
+	mutex_init(&i2c->mutex);
  	if (rec->mm_i2c ||
  	    (rec->hw_capable &&
  	     radeon_hw_i2c &&
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index 6ddf31a..b265a8b 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -191,6 +191,7 @@ struct radeon_i2c_chan {
  	struct radeon_i2c_bus_rec rec;
  	struct drm_dp_aux aux;
  	bool has_aux;
+	struct mutex mutex;
  };
  
  /* mostly for macs, but really any system without connector tables */

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