drm/radeon: program auxch directly (v2)

The atombios tables have an unfortunate restriction on only
being able to write 12 bytes, MST really wants 16-bytes here,
and since the hw can do it, we should just write directly to it.

This uses a module option to allow for it now, and maybe
we should provide the old code as a fallback for a while.

v2: (agd5f)
- move registers to a proper register header
- only enable on DCE5+
- enable by default on DCE5+
- Switch pad to aux mode before using it
- reformat instance handling to better match the
  rest of the driver

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_dp_auxch.c b/drivers/gpu/drm/radeon/radeon_dp_auxch.c
new file mode 100644
index 0000000..bf1fecc
--- /dev/null
+++ b/drivers/gpu/drm/radeon/radeon_dp_auxch.c
@@ -0,0 +1,206 @@
+/*
+ * Copyright 2015 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: Dave Airlie
+ */
+#include <drm/drmP.h>
+#include <drm/radeon_drm.h>
+#include "radeon.h"
+#include "nid.h"
+
+#define AUX_RX_ERROR_FLAGS (AUX_SW_RX_OVERFLOW |	     \
+			    AUX_SW_RX_HPD_DISCON |	     \
+			    AUX_SW_RX_PARTIAL_BYTE |	     \
+			    AUX_SW_NON_AUX_MODE |	     \
+			    AUX_SW_RX_MIN_COUNT_VIOL |	     \
+			    AUX_SW_RX_INVALID_STOP |	     \
+			    AUX_SW_RX_SYNC_INVALID_L |	     \
+			    AUX_SW_RX_SYNC_INVALID_H |	     \
+			    AUX_SW_RX_INVALID_START |	     \
+			    AUX_SW_RX_RECV_NO_DET |	     \
+			    AUX_SW_RX_RECV_INVALID_H |	     \
+			    AUX_SW_RX_RECV_INVALID_V)
+
+#define AUX_SW_REPLY_GET_BYTE_COUNT(x) (((x) >> 24) & 0x1f)
+
+#define BARE_ADDRESS_SIZE 3
+
+static const u32 aux_offset[] =
+{
+	0x6200 - 0x6200,
+	0x6250 - 0x6200,
+	0x62a0 - 0x6200,
+	0x6300 - 0x6200,
+	0x6350 - 0x6200,
+	0x63a0 - 0x6200,
+};
+
+ssize_t
+radeon_dp_aux_transfer_native(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
+{
+	struct radeon_i2c_chan *chan =
+		container_of(aux, struct radeon_i2c_chan, aux);
+	struct drm_device *dev = chan->dev;
+	struct radeon_device *rdev = dev->dev_private;
+	int ret = 0, i;
+	uint32_t tmp, ack = 0;
+	int instance = chan->rec.i2c_id & 0xf;
+	u8 byte;
+	u8 *buf = msg->buffer;
+	int retry_count = 0;
+	int bytes;
+	int msize;
+	bool is_write = false;
+
+	if (WARN_ON(msg->size > 16))
+		return -E2BIG;
+
+	switch (msg->request & ~DP_AUX_I2C_MOT) {
+	case DP_AUX_NATIVE_WRITE:
+	case DP_AUX_I2C_WRITE:
+		is_write = true;
+		break;
+	case DP_AUX_NATIVE_READ:
+	case DP_AUX_I2C_READ:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* work out two sizes required */
+	msize = 0;
+	bytes = BARE_ADDRESS_SIZE;
+	if (msg->size) {
+		msize = msg->size - 1;
+		bytes++;
+		if (is_write)
+			bytes += msg->size;
+	}
+
+	mutex_lock(&chan->mutex);
+
+	/* switch the pad to aux mode */
+	tmp = RREG32(chan->rec.mask_clk_reg);
+	tmp |= (1 << 16);
+	WREG32(chan->rec.mask_clk_reg, tmp);
+
+	/* setup AUX control register with correct HPD pin */
+	tmp = RREG32(AUX_CONTROL + aux_offset[instance]);
+
+	tmp &= AUX_HPD_SEL(0x7);
+	tmp |= AUX_HPD_SEL(chan->rec.hpd);
+	tmp |= AUX_EN | AUX_LS_READ_EN;
+
+	WREG32(AUX_CONTROL + aux_offset[instance], tmp);
+
+	/* atombios appears to write this twice lets copy it */
+	WREG32(AUX_SW_CONTROL + aux_offset[instance],
+	       AUX_SW_WR_BYTES(bytes));
+	WREG32(AUX_SW_CONTROL + aux_offset[instance],
+	       AUX_SW_WR_BYTES(bytes));
+
+	/* write the data header into the registers */
+	/* request, addres, msg size */
+	byte = (msg->request << 4);
+	WREG32(AUX_SW_DATA + aux_offset[instance],
+	       AUX_SW_DATA_MASK(byte) | AUX_SW_AUTOINCREMENT_DISABLE);
+
+	byte = (msg->address >> 8) & 0xff;
+	WREG32(AUX_SW_DATA + aux_offset[instance],
+	       AUX_SW_DATA_MASK(byte));
+
+	byte = msg->address & 0xff;
+	WREG32(AUX_SW_DATA + aux_offset[instance],
+	       AUX_SW_DATA_MASK(byte));
+
+	byte = msize;
+	WREG32(AUX_SW_DATA + aux_offset[instance],
+	       AUX_SW_DATA_MASK(byte));
+
+	/* if we are writing - write the msg buffer */
+	if (is_write) {
+		for (i = 0; i < msg->size; i++) {
+			WREG32(AUX_SW_DATA + aux_offset[instance],
+			       AUX_SW_DATA_MASK(buf[i]));
+		}
+	}
+
+	/* clear the ACK */
+	WREG32(AUX_SW_INTERRUPT_CONTROL + aux_offset[instance], AUX_SW_DONE_ACK);
+
+	/* write the size and GO bits */
+	WREG32(AUX_SW_CONTROL + aux_offset[instance],
+	       AUX_SW_WR_BYTES(bytes) | AUX_SW_GO);
+
+	/* poll the status registers - TODO irq support */
+	do {
+		tmp = RREG32(AUX_SW_STATUS + aux_offset[instance]);
+		if (tmp & AUX_SW_DONE) {
+			break;
+		}
+		usleep_range(100, 200);
+	} while (retry_count++ < 1000);
+
+	if (retry_count >= 1000) {
+		DRM_ERROR("auxch hw never signalled completion, error %08x\n", tmp);
+		ret = -EIO;
+		goto done;
+	}
+
+	if (tmp & AUX_SW_RX_TIMEOUT) {
+		DRM_DEBUG_KMS("dp_aux_ch timed out\n");
+		ret = -ETIMEDOUT;
+		goto done;
+	}
+	if (tmp & AUX_RX_ERROR_FLAGS) {
+		DRM_DEBUG_KMS("dp_aux_ch flags not zero: %08x\n", tmp);
+		ret = -EIO;
+		goto done;
+	}
+
+	bytes = AUX_SW_REPLY_GET_BYTE_COUNT(tmp);
+	if (bytes) {
+		WREG32(AUX_SW_DATA + aux_offset[instance],
+		       AUX_SW_DATA_RW | AUX_SW_AUTOINCREMENT_DISABLE);
+
+		tmp = RREG32(AUX_SW_DATA + aux_offset[instance]);
+		ack = (tmp >> 8) & 0xff;
+
+		for (i = 0; i < bytes - 1; i++) {
+			tmp = RREG32(AUX_SW_DATA + aux_offset[instance]);
+			if (buf)
+				buf[i] = (tmp >> 8) & 0xff;
+		}
+		if (buf)
+			ret = bytes - 1;
+	}
+
+	WREG32(AUX_SW_INTERRUPT_CONTROL + aux_offset[instance], AUX_SW_DONE_ACK);
+
+	if (is_write)
+		ret = msg->size;
+done:
+	mutex_unlock(&chan->mutex);
+
+	if (ret >= 0)
+		msg->reply = ack >> 4;
+	return ret;
+}