1 files changed, 541 insertions, 0 deletions
diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
new file mode 100644
index 000000000..84f9e3e5f
--- /dev/null
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -0,0 +1,541 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2012-2020, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/delay.h>
+#include <drm/drm_print.h>
+
+#include "dp_reg.h"
+#include "dp_aux.h"
+
+enum msm_dp_aux_err {
+	DP_AUX_ERR_NONE,
+	DP_AUX_ERR_ADDR,
+	DP_AUX_ERR_TOUT,
+	DP_AUX_ERR_NACK,
+	DP_AUX_ERR_DEFER,
+	DP_AUX_ERR_NACK_DEFER,
+	DP_AUX_ERR_PHY,
+};
+
+struct dp_aux_private {
+	struct device *dev;
+	struct dp_catalog *catalog;
+
+	struct mutex mutex;
+	struct completion comp;
+
+	enum msm_dp_aux_err aux_error_num;
+	u32 retry_cnt;
+	bool cmd_busy;
+	bool native;
+	bool read;
+	bool no_send_addr;
+	bool no_send_stop;
+	bool initted;
+	bool is_edp;
+	u32 offset;
+	u32 segment;
+
+	struct drm_dp_aux dp_aux;
+};
+
+#define MAX_AUX_RETRIES			5
+
+static ssize_t dp_aux_write(struct dp_aux_private *aux,
+			struct drm_dp_aux_msg *msg)
+{
+	u8 data[4];
+	u32 reg;
+	ssize_t len;
+	u8 *msgdata = msg->buffer;
+	int const AUX_CMD_FIFO_LEN = 128;
+	int i = 0;
+
+	if (aux->read)
+		len = 0;
+	else
+		len = msg->size;
+
+	/*
+	 * cmd fifo only has depth of 144 bytes
+	 * limit buf length to 128 bytes here
+	 */
+	if (len > AUX_CMD_FIFO_LEN - 4) {
+		DRM_ERROR("buf size greater than allowed size of 128 bytes\n");
+		return -EINVAL;
+	}
+
+	/* Pack cmd and write to HW */
+	data[0] = (msg->address >> 16) & 0xf;	/* addr[19:16] */
+	if (aux->read)
+		data[0] |=  BIT(4);		/* R/W */
+
+	data[1] = msg->address >> 8;		/* addr[15:8] */
+	data[2] = msg->address;			/* addr[7:0] */
+	data[3] = msg->size - 1;		/* len[7:0] */
+
+	for (i = 0; i < len + 4; i++) {
+		reg = (i < 4) ? data[i] : msgdata[i - 4];
+		reg <<= DP_AUX_DATA_OFFSET;
+		reg &= DP_AUX_DATA_MASK;
+		reg |= DP_AUX_DATA_WRITE;
+		/* index = 0, write */
+		if (i == 0)
+			reg |= DP_AUX_DATA_INDEX_WRITE;
+		aux->catalog->aux_data = reg;
+		dp_catalog_aux_write_data(aux->catalog);
+	}
+
+	dp_catalog_aux_clear_trans(aux->catalog, false);
+	dp_catalog_aux_clear_hw_interrupts(aux->catalog);
+
+	reg = 0; /* Transaction number == 1 */
+	if (!aux->native) { /* i2c */
+		reg |= DP_AUX_TRANS_CTRL_I2C;
+
+		if (aux->no_send_addr)
+			reg |= DP_AUX_TRANS_CTRL_NO_SEND_ADDR;
+
+		if (aux->no_send_stop)
+			reg |= DP_AUX_TRANS_CTRL_NO_SEND_STOP;
+	}
+
+	reg |= DP_AUX_TRANS_CTRL_GO;
+	aux->catalog->aux_data = reg;
+	dp_catalog_aux_write_trans(aux->catalog);
+
+	return len;
+}
+
+static ssize_t dp_aux_cmd_fifo_tx(struct dp_aux_private *aux,
+			      struct drm_dp_aux_msg *msg)
+{
+	ssize_t ret;
+	unsigned long time_left;
+
+	reinit_completion(&aux->comp);
+
+	ret = dp_aux_write(aux, msg);
+	if (ret < 0)
+		return ret;
+
+	time_left = wait_for_completion_timeout(&aux->comp,
+						msecs_to_jiffies(250));
+	if (!time_left)
+		return -ETIMEDOUT;
+
+	return ret;
+}
+
+static ssize_t dp_aux_cmd_fifo_rx(struct dp_aux_private *aux,
+		struct drm_dp_aux_msg *msg)
+{
+	u32 data;
+	u8 *dp;
+	u32 i, actual_i;
+	u32 len = msg->size;
+
+	dp_catalog_aux_clear_trans(aux->catalog, true);
+
+	data = DP_AUX_DATA_INDEX_WRITE; /* INDEX_WRITE */
+	data |= DP_AUX_DATA_READ;  /* read */
+
+	aux->catalog->aux_data = data;
+	dp_catalog_aux_write_data(aux->catalog);
+
+	dp = msg->buffer;
+
+	/* discard first byte */
+	data = dp_catalog_aux_read_data(aux->catalog);
+
+	for (i = 0; i < len; i++) {
+		data = dp_catalog_aux_read_data(aux->catalog);
+		*dp++ = (u8)((data >> DP_AUX_DATA_OFFSET) & 0xff);
+
+		actual_i = (data >> DP_AUX_DATA_INDEX_OFFSET) & 0xFF;
+		if (i != actual_i)
+			break;
+	}
+
+	return i;
+}
+
+static void dp_aux_update_offset_and_segment(struct dp_aux_private *aux,
+					     struct drm_dp_aux_msg *input_msg)
+{
+	u32 edid_address = 0x50;
+	u32 segment_address = 0x30;
+	bool i2c_read = input_msg->request &
+		(DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
+	u8 *data;
+
+	if (aux->native || i2c_read || ((input_msg->address != edid_address) &&
+		(input_msg->address != segment_address)))
+		return;
+
+
+	data = input_msg->buffer;
+	if (input_msg->address == segment_address)
+		aux->segment = *data;
+	else
+		aux->offset = *data;
+}
+
+/**
+ * dp_aux_transfer_helper() - helper function for EDID read transactions
+ *
+ * @aux: DP AUX private structure
+ * @input_msg: input message from DRM upstream APIs
+ * @send_seg: send the segment to sink
+ *
+ * return: void
+ *
+ * This helper function is used to fix EDID reads for non-compliant
+ * sinks that do not handle the i2c middle-of-transaction flag correctly.
+ */
+static void dp_aux_transfer_helper(struct dp_aux_private *aux,
+				   struct drm_dp_aux_msg *input_msg,
+				   bool send_seg)
+{
+	struct drm_dp_aux_msg helper_msg;
+	u32 message_size = 0x10;
+	u32 segment_address = 0x30;
+	u32 const edid_block_length = 0x80;
+	bool i2c_mot = input_msg->request & DP_AUX_I2C_MOT;
+	bool i2c_read = input_msg->request &
+		(DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
+
+	if (!i2c_mot || !i2c_read || (input_msg->size == 0))
+		return;
+
+	/*
+	 * Sending the segment value and EDID offset will be performed
+	 * from the DRM upstream EDID driver for each block. Avoid
+	 * duplicate AUX transactions related to this while reading the
+	 * first 16 bytes of each block.
+	 */
+	if (!(aux->offset % edid_block_length) || !send_seg)
+		goto end;
+
+	aux->read = false;
+	aux->cmd_busy = true;
+	aux->no_send_addr = true;
+	aux->no_send_stop = true;
+
+	/*
+	 * Send the segment address for every i2c read in which the
+	 * middle-of-tranaction flag is set. This is required to support EDID
+	 * reads of more than 2 blocks as the segment address is reset to 0
+	 * since we are overriding the middle-of-transaction flag for read
+	 * transactions.
+	 */
+
+	if (aux->segment) {
+		memset(&helper_msg, 0, sizeof(helper_msg));
+		helper_msg.address = segment_address;
+		helper_msg.buffer = &aux->segment;
+		helper_msg.size = 1;
+		dp_aux_cmd_fifo_tx(aux, &helper_msg);
+	}
+
+	/*
+	 * Send the offset address for every i2c read in which the
+	 * middle-of-transaction flag is set. This will ensure that the sink
+	 * will update its read pointer and return the correct portion of the
+	 * EDID buffer in the subsequent i2c read trasntion triggered in the
+	 * native AUX transfer function.
+	 */
+	memset(&helper_msg, 0, sizeof(helper_msg));
+	helper_msg.address = input_msg->address;
+	helper_msg.buffer = &aux->offset;
+	helper_msg.size = 1;
+	dp_aux_cmd_fifo_tx(aux, &helper_msg);
+
+end:
+	aux->offset += message_size;
+	if (aux->offset == 0x80 || aux->offset == 0x100)
+		aux->segment = 0x0; /* reset segment at end of block */
+}
+
+/*
+ * This function does the real job to process an AUX transaction.
+ * It will call aux_reset() function to reset the AUX channel,
+ * if the waiting is timeout.
+ */
+static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
+			       struct drm_dp_aux_msg *msg)
+{
+	ssize_t ret;
+	int const aux_cmd_native_max = 16;
+	int const aux_cmd_i2c_max = 128;
+	struct dp_aux_private *aux;
+
+	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
+
+	aux->native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);
+
+	/* Ignore address only message */
+	if (msg->size == 0 || !msg->buffer) {
+		msg->reply = aux->native ?
+			DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
+		return msg->size;
+	}
+
+	/* msg sanity check */
+	if ((aux->native && msg->size > aux_cmd_native_max) ||
+	    msg->size > aux_cmd_i2c_max) {
+		DRM_ERROR("%s: invalid msg: size(%zu), request(%x)\n",
+			__func__, msg->size, msg->request);
+		return -EINVAL;
+	}
+
+	mutex_lock(&aux->mutex);
+	if (!aux->initted) {
+		ret = -EIO;
+		goto exit;
+	}
+
+	/*
+	 * For eDP it's important to give a reasonably long wait here for HPD
+	 * to be asserted. This is because the panel driver may have _just_
+	 * turned on the panel and then tried to do an AUX transfer. The panel
+	 * driver has no way of knowing when the panel is ready, so it's up
+	 * to us to wait. For DP we never get into this situation so let's
+	 * avoid ever doing the extra long wait for DP.
+	 */
+	if (aux->is_edp) {
+		ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog);
+		if (ret) {
+			DRM_DEBUG_DP("Panel not ready for aux transactions\n");
+			goto exit;
+		}
+	}
+
+	dp_aux_update_offset_and_segment(aux, msg);
+	dp_aux_transfer_helper(aux, msg, true);
+
+	aux->read = msg->request & (DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
+	aux->cmd_busy = true;
+
+	if (aux->read) {
+		aux->no_send_addr = true;
+		aux->no_send_stop = false;
+	} else {
+		aux->no_send_addr = true;
+		aux->no_send_stop = true;
+	}
+
+	ret = dp_aux_cmd_fifo_tx(aux, msg);
+	if (ret < 0) {
+		if (aux->native) {
+			aux->retry_cnt++;
+			if (!(aux->retry_cnt % MAX_AUX_RETRIES))
+				dp_catalog_aux_update_cfg(aux->catalog);
+		}
+		/* reset aux if link is in connected state */
+		if (dp_catalog_link_is_connected(aux->catalog))
+			dp_catalog_aux_reset(aux->catalog);
+	} else {
+		aux->retry_cnt = 0;
+		switch (aux->aux_error_num) {
+		case DP_AUX_ERR_NONE:
+			if (aux->read)
+				ret = dp_aux_cmd_fifo_rx(aux, msg);
+			msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
+			break;
+		case DP_AUX_ERR_DEFER:
+			msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_DEFER : DP_AUX_I2C_REPLY_DEFER;
+			break;
+		case DP_AUX_ERR_PHY:
+		case DP_AUX_ERR_ADDR:
+		case DP_AUX_ERR_NACK:
+		case DP_AUX_ERR_NACK_DEFER:
+			msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_NACK : DP_AUX_I2C_REPLY_NACK;
+			break;
+		case DP_AUX_ERR_TOUT:
+			ret = -ETIMEDOUT;
+			break;
+		}
+	}
+
+	aux->cmd_busy = false;
+
+exit:
+	mutex_unlock(&aux->mutex);
+
+	return ret;
+}
+
+void dp_aux_isr(struct drm_dp_aux *dp_aux)
+{
+	u32 isr;
+	struct dp_aux_private *aux;
+
+	if (!dp_aux) {
+		DRM_ERROR("invalid input\n");
+		return;
+	}
+
+	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
+
+	isr = dp_catalog_aux_get_irq(aux->catalog);
+
+	/* no interrupts pending, return immediately */
+	if (!isr)
+		return;
+
+	if (!aux->cmd_busy) {
+		DRM_ERROR("Unexpected DP AUX IRQ %#010x when not busy\n", isr);
+		return;
+	}
+
+	/*
+	 * The logic below assumes only one error bit is set (other than "done"
+	 * which can apparently be set at the same time as some of the other
+	 * bits). Warn if more than one get set so we know we need to improve
+	 * the logic.
+	 */
+	if (hweight32(isr & ~DP_INTR_AUX_XFER_DONE) > 1)
+		DRM_WARN("Some DP AUX interrupts unhandled: %#010x\n", isr);
+
+	if (isr & DP_INTR_AUX_ERROR) {
+		aux->aux_error_num = DP_AUX_ERR_PHY;
+		dp_catalog_aux_clear_hw_interrupts(aux->catalog);
+	} else if (isr & DP_INTR_NACK_DEFER) {
+		aux->aux_error_num = DP_AUX_ERR_NACK_DEFER;
+	} else if (isr & DP_INTR_WRONG_ADDR) {
+		aux->aux_error_num = DP_AUX_ERR_ADDR;
+	} else if (isr & DP_INTR_TIMEOUT) {
+		aux->aux_error_num = DP_AUX_ERR_TOUT;
+	} else if (!aux->native && (isr & DP_INTR_I2C_NACK)) {
+		aux->aux_error_num = DP_AUX_ERR_NACK;
+	} else if (!aux->native && (isr & DP_INTR_I2C_DEFER)) {
+		if (isr & DP_INTR_AUX_XFER_DONE)
+			aux->aux_error_num = DP_AUX_ERR_NACK;
+		else
+			aux->aux_error_num = DP_AUX_ERR_DEFER;
+	} else if (isr & DP_INTR_AUX_XFER_DONE) {
+		aux->aux_error_num = DP_AUX_ERR_NONE;
+	} else {
+		DRM_WARN("Unexpected interrupt: %#010x\n", isr);
+		return;
+	}
+
+	complete(&aux->comp);
+}
+
+void dp_aux_reconfig(struct drm_dp_aux *dp_aux)
+{
+	struct dp_aux_private *aux;
+
+	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
+
+	dp_catalog_aux_update_cfg(aux->catalog);
+	dp_catalog_aux_reset(aux->catalog);
+}
+
+void dp_aux_init(struct drm_dp_aux *dp_aux)
+{
+	struct dp_aux_private *aux;
+
+	if (!dp_aux) {
+		DRM_ERROR("invalid input\n");
+		return;
+	}
+
+	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
+
+	mutex_lock(&aux->mutex);
+
+	dp_catalog_aux_enable(aux->catalog, true);
+	aux->retry_cnt = 0;
+	aux->initted = true;
+
+	mutex_unlock(&aux->mutex);
+}
+
+void dp_aux_deinit(struct drm_dp_aux *dp_aux)
+{
+	struct dp_aux_private *aux;
+
+	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
+
+	mutex_lock(&aux->mutex);
+
+	aux->initted = false;
+	dp_catalog_aux_enable(aux->catalog, false);
+
+	mutex_unlock(&aux->mutex);
+}
+
+int dp_aux_register(struct drm_dp_aux *dp_aux)
+{
+	struct dp_aux_private *aux;
+	int ret;
+
+	if (!dp_aux) {
+		DRM_ERROR("invalid input\n");
+		return -EINVAL;
+	}
+
+	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
+
+	aux->dp_aux.name = "dpu_dp_aux";
+	aux->dp_aux.dev = aux->dev;
+	aux->dp_aux.transfer = dp_aux_transfer;
+	ret = drm_dp_aux_register(&aux->dp_aux);
+	if (ret) {
+		DRM_ERROR("%s: failed to register drm aux: %d\n", __func__,
+				ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+void dp_aux_unregister(struct drm_dp_aux *dp_aux)
+{
+	drm_dp_aux_unregister(dp_aux);
+}
+
+struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
+			      bool is_edp)
+{
+	struct dp_aux_private *aux;
+
+	if (!catalog) {
+		DRM_ERROR("invalid input\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	aux = devm_kzalloc(dev, sizeof(*aux), GFP_KERNEL);
+	if (!aux)
+		return ERR_PTR(-ENOMEM);
+
+	init_completion(&aux->comp);
+	aux->cmd_busy = false;
+	aux->is_edp = is_edp;
+	mutex_init(&aux->mutex);
+
+	aux->dev = dev;
+	aux->catalog = catalog;
+	aux->retry_cnt = 0;
+
+	return &aux->dp_aux;
+}
+
+void dp_aux_put(struct drm_dp_aux *dp_aux)
+{
+	struct dp_aux_private *aux;
+
+	if (!dp_aux)
+		return;
+
+	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
+
+	mutex_destroy(&aux->mutex);
+
+	devm_kfree(aux->dev, aux);
+}