1 files changed, 324 insertions, 37 deletions

diff --git a/drivers/spi/spi-bcm63xx-hsspi.c b/drivers/spi/spi-bcm63xx-hsspi.c
index bc700649d270..6a289deb5848 100644
--- a/drivers/spi/spi-bcm63xx-hsspi.c
+++ b/drivers/spi/spi-bcm63xx-hsspi.c
@@ -93,7 +93,11 @@
 
 #define HSSPI_MAX_PREPEND_LEN			15
 
-#define HSSPI_MAX_SYNC_CLOCK			30000000
+/*
+ * Some chip require 30MHz but other require 25MHz. Use smaller value to cover
+ * both cases.
+ */
+#define HSSPI_MAX_SYNC_CLOCK			25000000
 
 #define HSSPI_SPI_MAX_CS			8
 #define HSSPI_BUS_NUM				1 /* 0 is legacy SPI */
@@ -103,6 +107,24 @@
 #define HSSPI_WAIT_MODE_INTR		1
 #define HSSPI_WAIT_MODE_MAX			HSSPI_WAIT_MODE_INTR
 
+/*
+ * Default transfer mode is auto. If the msg is prependable, use the prepend
+ * mode.  If not, falls back to use the dummy cs workaround mode but limit the
+ * clock to 25MHz to make sure it works in all board design.
+ */
+#define HSSPI_XFER_MODE_AUTO		0
+#define HSSPI_XFER_MODE_PREPEND		1
+#define HSSPI_XFER_MODE_DUMMYCS		2
+#define HSSPI_XFER_MODE_MAX			HSSPI_XFER_MODE_DUMMYCS
+
+#define bcm63xx_prepend_printk_on_checkfail(bs, fmt, ...)	\
+do {										\
+	if (bs->xfer_mode == HSSPI_XFER_MODE_AUTO)				\
+		dev_dbg(&bs->pdev->dev, fmt, ##__VA_ARGS__);		\
+	else if (bs->xfer_mode == HSSPI_XFER_MODE_PREPEND)		\
+		dev_err(&bs->pdev->dev, fmt, ##__VA_ARGS__);		\
+} while (0)
+
 struct bcm63xx_hsspi {
 	struct completion done;
 	struct mutex bus_mutex;
@@ -116,6 +138,9 @@ struct bcm63xx_hsspi {
 	u32 speed_hz;
 	u8 cs_polarity;
 	u32 wait_mode;
+	u32 xfer_mode;
+	u32 prepend_cnt;
+	u8 *prepend_buf;
 };
 
 static ssize_t wait_mode_show(struct device *dev, struct device_attribute *attr,
@@ -154,8 +179,42 @@ static ssize_t wait_mode_store(struct device *dev, struct device_attribute *attr
 
 static DEVICE_ATTR_RW(wait_mode);
 
+static ssize_t xfer_mode_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct spi_controller *ctrl = dev_get_drvdata(dev);
+	struct bcm63xx_hsspi *bs = spi_master_get_devdata(ctrl);
+
+	return sprintf(buf, "%d\n", bs->xfer_mode);
+}
+
+static ssize_t xfer_mode_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	struct spi_controller *ctrl = dev_get_drvdata(dev);
+	struct bcm63xx_hsspi *bs = spi_master_get_devdata(ctrl);
+	u32 val;
+
+	if (kstrtou32(buf, 10, &val))
+		return -EINVAL;
+
+	if (val > HSSPI_XFER_MODE_MAX) {
+		dev_warn(dev, "invalid xfer mode %u\n", val);
+		return -EINVAL;
+	}
+
+	mutex_lock(&bs->msg_mutex);
+	bs->xfer_mode = val;
+	mutex_unlock(&bs->msg_mutex);
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(xfer_mode);
+
 static struct attribute *bcm63xx_hsspi_attrs[] = {
 	&dev_attr_wait_mode.attr,
+	&dev_attr_xfer_mode.attr,
 	NULL,
 };
 
@@ -163,6 +222,203 @@ static const struct attribute_group bcm63xx_hsspi_group = {
 	.attrs = bcm63xx_hsspi_attrs,
 };
 
+static void bcm63xx_hsspi_set_clk(struct bcm63xx_hsspi *bs,
+				  struct spi_device *spi, int hz);
+
+static size_t bcm63xx_hsspi_max_message_size(struct spi_device *spi)
+{
+	return HSSPI_BUFFER_LEN - HSSPI_OPCODE_LEN;
+}
+
+static int bcm63xx_hsspi_wait_cmd(struct bcm63xx_hsspi *bs)
+{
+	unsigned long limit;
+	u32 reg = 0;
+	int rc = 0;
+
+	if (bs->wait_mode == HSSPI_WAIT_MODE_INTR) {
+		if (wait_for_completion_timeout(&bs->done, HZ) == 0)
+			rc = 1;
+	} else {
+		/* polling mode checks for status busy bit */
+		limit = jiffies + msecs_to_jiffies(HSSPI_POLL_STATUS_TIMEOUT_MS);
+
+		while (!time_after(jiffies, limit)) {
+			reg = __raw_readl(bs->regs + HSSPI_PINGPONG_STATUS_REG(0));
+			if (reg & HSSPI_PINGPONG_STATUS_SRC_BUSY)
+				cpu_relax();
+			else
+				break;
+		}
+		if (reg & HSSPI_PINGPONG_STATUS_SRC_BUSY)
+			rc = 1;
+	}
+
+	if (rc)
+		dev_err(&bs->pdev->dev, "transfer timed out!\n");
+
+	return rc;
+}
+
+static bool bcm63xx_prepare_prepend_transfer(struct spi_master *master,
+					  struct spi_message *msg,
+					  struct spi_transfer *t_prepend)
+{
+
+	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
+	bool tx_only = false;
+	struct spi_transfer *t;
+
+	/*
+	 * Multiple transfers within a message may be combined into one transfer
+	 * to the controller using its prepend feature. A SPI message is prependable
+	 * only if the following are all true:
+	 *   1. One or more half duplex write transfer in single bit mode
+	 *   2. Optional full duplex read/write at the end
+	 *   3. No delay and cs_change between transfers
+	 */
+	bs->prepend_cnt = 0;
+	list_for_each_entry(t, &msg->transfers, transfer_list) {
+		if ((spi_delay_to_ns(&t->delay, t) > 0) || t->cs_change) {
+			bcm63xx_prepend_printk_on_checkfail(bs,
+				 "Delay or cs change not supported in prepend mode!\n");
+			return false;
+		}
+
+		tx_only = false;
+		if (t->tx_buf && !t->rx_buf) {
+			tx_only = true;
+			if (bs->prepend_cnt + t->len >
+				(HSSPI_BUFFER_LEN - HSSPI_OPCODE_LEN)) {
+				bcm63xx_prepend_printk_on_checkfail(bs,
+					 "exceed max buf len, abort prepending transfers!\n");
+				return false;
+			}
+
+			if (t->tx_nbits > SPI_NBITS_SINGLE &&
+				!list_is_last(&t->transfer_list, &msg->transfers)) {
+				bcm63xx_prepend_printk_on_checkfail(bs,
+					 "multi-bit prepend buf not supported!\n");
+				return false;
+			}
+
+			if (t->tx_nbits == SPI_NBITS_SINGLE) {
+				memcpy(bs->prepend_buf + bs->prepend_cnt, t->tx_buf, t->len);
+				bs->prepend_cnt += t->len;
+			}
+		} else {
+			if (!list_is_last(&t->transfer_list, &msg->transfers)) {
+				bcm63xx_prepend_printk_on_checkfail(bs,
+					 "rx/tx_rx transfer not supported when it is not last one!\n");
+				return false;
+			}
+		}
+
+		if (list_is_last(&t->transfer_list, &msg->transfers)) {
+			memcpy(t_prepend, t, sizeof(struct spi_transfer));
+
+			if (tx_only && t->tx_nbits == SPI_NBITS_SINGLE) {
+				/*
+				 * if the last one is also a single bit tx only transfer, merge
+				 * all of them into one single tx transfer
+				 */
+				t_prepend->len = bs->prepend_cnt;
+				t_prepend->tx_buf = bs->prepend_buf;
+				bs->prepend_cnt = 0;
+			} else {
+				/*
+				 * if the last one is not a tx only transfer or dual tx xfer, all
+				 * the previous transfers are sent through prepend bytes and
+				 * make sure it does not exceed the max prepend len
+				 */
+				if (bs->prepend_cnt > HSSPI_MAX_PREPEND_LEN) {
+					bcm63xx_prepend_printk_on_checkfail(bs,
+						"exceed max prepend len, abort prepending transfers!\n");
+					return false;
+				}
+			}
+		}
+	}
+
+	return true;
+}
+
+static int bcm63xx_hsspi_do_prepend_txrx(struct spi_device *spi,
+					 struct spi_transfer *t)
+{
+	struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
+	unsigned int chip_select = spi->chip_select;
+	u16 opcode = 0;
+	const u8 *tx = t->tx_buf;
+	u8 *rx = t->rx_buf;
+	u32 reg = 0;
+
+	/*
+	 * shouldn't happen as we set the max_message_size in the probe.
+	 * but check it again in case some driver does not honor the max size
+	 */
+	if (t->len + bs->prepend_cnt > (HSSPI_BUFFER_LEN - HSSPI_OPCODE_LEN)) {
+		dev_warn(&bs->pdev->dev,
+			 "Prepend message large than fifo size len %d prepend %d\n",
+			 t->len, bs->prepend_cnt);
+		return -EINVAL;
+	}
+
+	bcm63xx_hsspi_set_clk(bs, spi, t->speed_hz);
+
+	if (tx && rx)
+		opcode = HSSPI_OP_READ_WRITE;
+	else if (tx)
+		opcode = HSSPI_OP_WRITE;
+	else if (rx)
+		opcode = HSSPI_OP_READ;
+
+	if ((opcode == HSSPI_OP_READ && t->rx_nbits == SPI_NBITS_DUAL) ||
+	    (opcode == HSSPI_OP_WRITE && t->tx_nbits == SPI_NBITS_DUAL)) {
+		opcode |= HSSPI_OP_MULTIBIT;
+
+		if (t->rx_nbits == SPI_NBITS_DUAL) {
+			reg |= 1 << MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT;
+			reg |= bs->prepend_cnt << MODE_CTRL_MULTIDATA_RD_STRT_SHIFT;
+		}
+		if (t->tx_nbits == SPI_NBITS_DUAL) {
+			reg |= 1 << MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT;
+			reg |= bs->prepend_cnt << MODE_CTRL_MULTIDATA_WR_STRT_SHIFT;
+		}
+	}
+
+	reg |= bs->prepend_cnt << MODE_CTRL_PREPENDBYTE_CNT_SHIFT;
+	__raw_writel(reg | 0xff,
+		     bs->regs + HSSPI_PROFILE_MODE_CTRL_REG(chip_select));
+
+	reinit_completion(&bs->done);
+	if (bs->prepend_cnt)
+		memcpy_toio(bs->fifo + HSSPI_OPCODE_LEN, bs->prepend_buf,
+			    bs->prepend_cnt);
+	if (tx)
+		memcpy_toio(bs->fifo + HSSPI_OPCODE_LEN + bs->prepend_cnt, tx,
+			    t->len);
+
+	__raw_writew((u16)cpu_to_be16(opcode | t->len), bs->fifo);
+	/* enable interrupt */
+	if (bs->wait_mode == HSSPI_WAIT_MODE_INTR)
+		__raw_writel(HSSPI_PINGx_CMD_DONE(0), bs->regs + HSSPI_INT_MASK_REG);
+
+	/* start the transfer */
+	reg = chip_select << PINGPONG_CMD_SS_SHIFT |
+	    chip_select << PINGPONG_CMD_PROFILE_SHIFT |
+	    PINGPONG_COMMAND_START_NOW;
+	__raw_writel(reg, bs->regs + HSSPI_PINGPONG_COMMAND_REG(0));
+
+	if (bcm63xx_hsspi_wait_cmd(bs))
+		return -ETIMEDOUT;
+
+	if (rx)
+		memcpy_fromio(rx, bs->fifo, t->len);
+
+	return 0;
+}
+
 static void bcm63xx_hsspi_set_cs(struct bcm63xx_hsspi *bs, unsigned int cs,
 				 bool active)
 {
@@ -215,8 +471,7 @@ static int bcm63xx_hsspi_do_txrx(struct spi_device *spi, struct spi_transfer *t)
 	int step_size = HSSPI_BUFFER_LEN;
 	const u8 *tx = t->tx_buf;
 	u8 *rx = t->rx_buf;
-	u32 val = 0;
-	unsigned long limit;
+	u32 reg = 0;
 
 	bcm63xx_hsspi_set_clk(bs, spi, t->speed_hz);
 	if (!t->cs_off)
@@ -237,12 +492,12 @@ static int bcm63xx_hsspi_do_txrx(struct spi_device *spi, struct spi_transfer *t)
 		opcode |= HSSPI_OP_MULTIBIT;
 
 		if (t->rx_nbits == SPI_NBITS_DUAL)
-			val |= 1 << MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT;
+			reg |= 1 << MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT;
 		if (t->tx_nbits == SPI_NBITS_DUAL)
-			val |= 1 << MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT;
+			reg |= 1 << MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT;
 	}
 
-	__raw_writel(val | 0xff,
+	__raw_writel(reg | 0xff,
 		     bs->regs + HSSPI_PROFILE_MODE_CTRL_REG(chip_select));
 
 	while (pending > 0) {
@@ -261,28 +516,13 @@ static int bcm63xx_hsspi_do_txrx(struct spi_device *spi, struct spi_transfer *t)
 			__raw_writel(HSSPI_PINGx_CMD_DONE(0),
 				     bs->regs + HSSPI_INT_MASK_REG);
 
-		/* start the transfer */
-		__raw_writel(!chip_select << PINGPONG_CMD_SS_SHIFT |
-			     chip_select << PINGPONG_CMD_PROFILE_SHIFT |
-			     PINGPONG_COMMAND_START_NOW,
-			     bs->regs + HSSPI_PINGPONG_COMMAND_REG(0));
+		reg =  !chip_select << PINGPONG_CMD_SS_SHIFT |
+			    chip_select << PINGPONG_CMD_PROFILE_SHIFT |
+			    PINGPONG_COMMAND_START_NOW;
+		__raw_writel(reg, bs->regs + HSSPI_PINGPONG_COMMAND_REG(0));
 
-		if (bs->wait_mode == HSSPI_WAIT_MODE_INTR) {
-			if (wait_for_completion_timeout(&bs->done, HZ) == 0)
-				goto err_timeout;
-		} else {
-			/* polling mode checks for status busy bit */
-			limit = jiffies + msecs_to_jiffies(HSSPI_POLL_STATUS_TIMEOUT_MS);
-			while (!time_after(jiffies, limit)) {
-				val = __raw_readl(bs->regs + HSSPI_PINGPONG_STATUS_REG(0));
-				if (val & HSSPI_PINGPONG_STATUS_SRC_BUSY)
-					cpu_relax();
-				else
-					break;
-			}
-			if (val & HSSPI_PINGPONG_STATUS_SRC_BUSY)
-				goto err_timeout;
-		}
+		if (bcm63xx_hsspi_wait_cmd(bs))
+			return -ETIMEDOUT;
 
 		if (rx) {
 			memcpy_fromio(rx, bs->fifo, curr_step);
@@ -293,10 +533,6 @@ static int bcm63xx_hsspi_do_txrx(struct spi_device *spi, struct spi_transfer *t)
 	}
 
 	return 0;
-
-err_timeout:
-	dev_err(&bs->pdev->dev, "transfer timed out!\n");
-	return -ETIMEDOUT;
 }
 
 static int bcm63xx_hsspi_setup(struct spi_device *spi)
@@ -336,18 +572,17 @@ static int bcm63xx_hsspi_setup(struct spi_device *spi)
 	return 0;
 }
 
-static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
+static int bcm63xx_hsspi_do_dummy_cs_txrx(struct spi_device *spi,
 				      struct spi_message *msg)
 {
-	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
-	struct spi_transfer *t;
-	struct spi_device *spi = msg->spi;
+	struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
 	int status = -EINVAL;
 	int dummy_cs;
 	bool keep_cs = false;
+	struct spi_transfer *t;
 
-	mutex_lock(&bs->msg_mutex);
-	/* This controller does not support keeping CS active during idle.
+	/*
+	 * This controller does not support keeping CS active during idle.
 	 * To work around this, we use the following ugly hack:
 	 *
 	 * a. Invert the target chip select's polarity so it will be active.
@@ -365,6 +600,21 @@ static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
 	bcm63xx_hsspi_set_cs(bs, dummy_cs, true);
 
 	list_for_each_entry(t, &msg->transfers, transfer_list) {
+		/*
+		 * We are here because one of reasons below:
+		 * a. Message is not prependable and in default auto xfer mode. This mean
+		 *    we fallback to dummy cs mode at maximum 25MHz safe clock rate.
+		 * b. User set to use the dummy cs mode.
+		 */
+		if (bs->xfer_mode == HSSPI_XFER_MODE_AUTO) {
+			if (t->speed_hz > HSSPI_MAX_SYNC_CLOCK) {
+				t->speed_hz = HSSPI_MAX_SYNC_CLOCK;
+				dev_warn_once(&bs->pdev->dev,
+					"Force to dummy cs mode. Reduce the speed to %dHz",
+					t->speed_hz);
+			}
+		}
+
 		status = bcm63xx_hsspi_do_txrx(spi, t);
 		if (status)
 			break;
@@ -396,6 +646,35 @@ static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
 	if (status || !keep_cs)
 		bcm63xx_hsspi_set_cs(bs, spi->chip_select, false);
 
+	return status;
+}
+
+static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
+				      struct spi_message *msg)
+{
+	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
+	struct spi_device *spi = msg->spi;
+	int status = -EINVAL;
+	bool prependable = false;
+	struct spi_transfer t_prepend;
+
+	mutex_lock(&bs->msg_mutex);
+
+	if (bs->xfer_mode != HSSPI_XFER_MODE_DUMMYCS)
+		prependable = bcm63xx_prepare_prepend_transfer(master, msg, &t_prepend);
+
+	if (prependable) {
+		status = bcm63xx_hsspi_do_prepend_txrx(spi, &t_prepend);
+		msg->actual_length = (t_prepend.len + bs->prepend_cnt);
+	} else {
+		if (bs->xfer_mode == HSSPI_XFER_MODE_PREPEND) {
+			dev_err(&bs->pdev->dev,
+				"User sets prepend mode but msg not prependable! Abort transfer\n");
+			status = -EINVAL;
+		} else
+			status = bcm63xx_hsspi_do_dummy_cs_txrx(spi, msg);
+	}
+
 	mutex_unlock(&bs->msg_mutex);
 	msg->status = status;
 	spi_finalize_current_message(master);
@@ -490,6 +769,11 @@ static int bcm63xx_hsspi_probe(struct platform_device *pdev)
 	bs->speed_hz = rate;
 	bs->fifo = (u8 __iomem *)(bs->regs + HSSPI_FIFO_REG(0));
 	bs->wait_mode = HSSPI_WAIT_MODE_POLLING;
+	bs->prepend_buf = devm_kzalloc(dev, HSSPI_BUFFER_LEN, GFP_KERNEL);
+	if (!bs->prepend_buf) {
+		ret = -ENOMEM;
+		goto out_put_master;
+	}
 
 	mutex_init(&bs->bus_mutex);
 	mutex_init(&bs->msg_mutex);
@@ -508,6 +792,9 @@ static int bcm63xx_hsspi_probe(struct platform_device *pdev)
 	master->num_chipselect = num_cs;
 	master->setup = bcm63xx_hsspi_setup;
 	master->transfer_one_message = bcm63xx_hsspi_transfer_one;
+	master->max_transfer_size = bcm63xx_hsspi_max_message_size;
+	master->max_message_size = bcm63xx_hsspi_max_message_size;
+
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH |
 			    SPI_RX_DUAL | SPI_TX_DUAL;
 	master->bits_per_word_mask = SPI_BPW_MASK(8);