1 files changed, 535 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 000000000000..19b35ae3e927
--- /dev/null
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -0,0 +1,535 @@
+// 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"
+
+#define DP_AUX_ENUM_STR(x)		#x
+
+struct dp_aux_private {
+	struct device *dev;
+	struct dp_catalog *catalog;
+
+	struct mutex mutex;
+	struct completion comp;
+
+	u32 aux_error_num;
+	u32 retry_cnt;
+	bool cmd_busy;
+	bool native;
+	bool read;
+	bool no_send_addr;
+	bool no_send_stop;
+	u32 offset;
+	u32 segment;
+	u32 isr;
+
+	struct drm_dp_aux dp_aux;
+};
+
+static const char *dp_aux_get_error(u32 aux_error)
+{
+	switch (aux_error) {
+	case DP_AUX_ERR_NONE:
+		return DP_AUX_ENUM_STR(DP_AUX_ERR_NONE);
+	case DP_AUX_ERR_ADDR:
+		return DP_AUX_ENUM_STR(DP_AUX_ERR_ADDR);
+	case DP_AUX_ERR_TOUT:
+		return DP_AUX_ENUM_STR(DP_AUX_ERR_TOUT);
+	case DP_AUX_ERR_NACK:
+		return DP_AUX_ENUM_STR(DP_AUX_ERR_NACK);
+	case DP_AUX_ERR_DEFER:
+		return DP_AUX_ENUM_STR(DP_AUX_ERR_DEFER);
+	case DP_AUX_ERR_NACK_DEFER:
+		return DP_AUX_ENUM_STR(DP_AUX_ERR_NACK_DEFER);
+	default:
+		return "unknown";
+	}
+}
+
+static u32 dp_aux_write(struct dp_aux_private *aux,
+			struct drm_dp_aux_msg *msg)
+{
+	u32 data[4], reg, len;
+	u8 *msgdata = msg->buffer;
+	int const AUX_CMD_FIFO_LEN = 128;
+	int i = 0;
+
+	if (aux->read)
+		len = 4;
+	else
+		len = msg->size + 4;
+
+	/*
+	 * cmd fifo only has depth of 144 bytes
+	 * limit buf length to 128 bytes here
+	 */
+	if (len > AUX_CMD_FIFO_LEN) {
+		DRM_ERROR("buf size greater than allowed size of 128 bytes\n");
+		return 0;
+	}
+
+	/* 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) & 0xff;	/* addr[15:8] */
+	data[2] = msg->address & 0xff;		/* addr[7:0] */
+	data[3] = (msg->size - 1) & 0xff;	/* len[7:0] */
+
+	for (i = 0; i < len; i++) {
+		reg = (i < 4) ? data[i] : msgdata[i - 4];
+		/* index = 0, write */
+		reg = (((reg) << DP_AUX_DATA_OFFSET)
+		       & DP_AUX_DATA_MASK) | DP_AUX_DATA_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 int dp_aux_cmd_fifo_tx(struct dp_aux_private *aux,
+			      struct drm_dp_aux_msg *msg)
+{
+	u32 ret, len, timeout;
+	int aux_timeout_ms = HZ/4;
+
+	reinit_completion(&aux->comp);
+
+	len = dp_aux_write(aux, msg);
+	if (len == 0) {
+		DRM_ERROR("DP AUX write failed\n");
+		return -EINVAL;
+	}
+
+	timeout = wait_for_completion_timeout(&aux->comp, aux_timeout_ms);
+	if (!timeout) {
+		DRM_ERROR("aux %s timeout\n", (aux->read ? "read" : "write"));
+		return -ETIMEDOUT;
+	}
+
+	if (aux->aux_error_num == DP_AUX_ERR_NONE) {
+		ret = len;
+	} else {
+		DRM_ERROR_RATELIMITED("aux err: %s\n",
+			dp_aux_get_error(aux->aux_error_num));
+
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static void 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)
+			DRM_ERROR("Index mismatch: expected %d, found %d\n",
+				i, actual_i);
+	}
+}
+
+static void dp_aux_native_handler(struct dp_aux_private *aux)
+{
+	u32 isr = aux->isr;
+
+	if (isr & DP_INTR_AUX_I2C_DONE)
+		aux->aux_error_num = DP_AUX_ERR_NONE;
+	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;
+	if (isr & DP_INTR_NACK_DEFER)
+		aux->aux_error_num = DP_AUX_ERR_NACK;
+	if (isr & DP_INTR_AUX_ERROR) {
+		aux->aux_error_num = DP_AUX_ERR_PHY;
+		dp_catalog_aux_clear_hw_interrupts(aux->catalog);
+	}
+
+	complete(&aux->comp);
+}
+
+static void dp_aux_i2c_handler(struct dp_aux_private *aux)
+{
+	u32 isr = aux->isr;
+
+	if (isr & DP_INTR_AUX_I2C_DONE) {
+		if (isr & (DP_INTR_I2C_NACK | DP_INTR_I2C_DEFER))
+			aux->aux_error_num = DP_AUX_ERR_NACK;
+		else
+			aux->aux_error_num = DP_AUX_ERR_NONE;
+	} 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;
+		if (isr & DP_INTR_NACK_DEFER)
+			aux->aux_error_num = DP_AUX_ERR_NACK_DEFER;
+		if (isr & DP_INTR_I2C_NACK)
+			aux->aux_error_num = DP_AUX_ERR_NACK;
+		if (isr & DP_INTR_I2C_DEFER)
+			aux->aux_error_num = DP_AUX_ERR_DEFER;
+		if (isr & DP_INTR_AUX_ERROR) {
+			aux->aux_error_num = DP_AUX_ERR_PHY;
+			dp_catalog_aux_clear_hw_interrupts(aux->catalog);
+		}
+	}
+
+	complete(&aux->comp);
+}
+
+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;
+	int const retry_count = 5;
+	struct dp_aux_private *aux = container_of(dp_aux,
+		struct dp_aux_private, dp_aux);
+
+	mutex_lock(&aux->mutex);
+
+	aux->native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);
+
+	/* Ignore address only message */
+	if ((msg->size == 0) || (msg->buffer == NULL)) {
+		msg->reply = aux->native ?
+			DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
+		ret = msg->size;
+		goto unlock_exit;
+	}
+
+	/* 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);
+		ret = -EINVAL;
+		goto unlock_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 % retry_count))
+				dp_catalog_aux_update_cfg(aux->catalog);
+			dp_catalog_aux_reset(aux->catalog);
+		}
+		usleep_range(400, 500); /* at least 400us to next try */
+		goto unlock_exit;
+	}
+
+	if (aux->aux_error_num == DP_AUX_ERR_NONE) {
+		if (aux->read)
+			dp_aux_cmd_fifo_rx(aux, msg);
+
+		msg->reply = aux->native ?
+			DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
+	} else {
+		/* Reply defer to retry */
+		msg->reply = aux->native ?
+			DP_AUX_NATIVE_REPLY_DEFER : DP_AUX_I2C_REPLY_DEFER;
+	}
+
+	/* Return requested size for success or retry */
+	ret = msg->size;
+	aux->retry_cnt = 0;
+
+unlock_exit:
+	aux->cmd_busy = false;
+	mutex_unlock(&aux->mutex);
+	return ret;
+}
+
+void dp_aux_isr(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);
+
+	aux->isr = dp_catalog_aux_get_irq(aux->catalog);
+
+	if (!aux->cmd_busy)
+		return;
+
+	if (aux->native)
+		dp_aux_native_handler(aux);
+	else
+		dp_aux_i2c_handler(aux);
+}
+
+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);
+
+	dp_catalog_aux_enable(aux->catalog, true);
+	aux->retry_cnt = 0;
+}
+
+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);
+
+	dp_catalog_aux_enable(aux->catalog, false);
+}
+
+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)
+{
+	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;
+	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);
+}