1 files changed, 79 insertions, 66 deletions

diff --git a/drivers/fpga/microchip-spi.c b/drivers/fpga/microchip-spi.c
index 7436976ea904..d6070e7f5205 100644
--- a/drivers/fpga/microchip-spi.c
+++ b/drivers/fpga/microchip-spi.c
@@ -6,6 +6,7 @@
 #include <asm/unaligned.h>
 #include <linux/delay.h>
 #include <linux/fpga/fpga-mgr.h>
+#include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/spi/spi.h>
@@ -33,7 +34,7 @@
 
 #define	MPF_BITS_PER_COMPONENT_SIZE	22
 
-#define	MPF_STATUS_POLL_RETRIES		10000
+#define	MPF_STATUS_POLL_TIMEOUT		(2 * USEC_PER_SEC)
 #define	MPF_STATUS_BUSY			BIT(0)
 #define	MPF_STATUS_READY		BIT(1)
 #define	MPF_STATUS_SPI_VIOLATION	BIT(2)
@@ -42,46 +43,55 @@
 struct mpf_priv {
 	struct spi_device *spi;
 	bool program_mode;
+	u8 tx __aligned(ARCH_KMALLOC_MINALIGN);
+	u8 rx;
 };
 
-static int mpf_read_status(struct spi_device *spi)
+static int mpf_read_status(struct mpf_priv *priv)
 {
-	u8 status = 0, status_command = MPF_SPI_READ_STATUS;
-	struct spi_transfer xfers[2] = { 0 };
-	int ret;
-
 	/*
 	 * HW status is returned on MISO in the first byte after CS went
 	 * active. However, first reading can be inadequate, so we submit
 	 * two identical SPI transfers and use result of the later one.
 	 */
-	xfers[0].tx_buf = &status_command;
-	xfers[1].tx_buf = &status_command;
-	xfers[0].rx_buf = &status;
-	xfers[1].rx_buf = &status;
-	xfers[0].len = 1;
-	xfers[1].len = 1;
-	xfers[0].cs_change = 1;
+	struct spi_transfer xfers[2] = {
+		{
+			.tx_buf = &priv->tx,
+			.rx_buf = &priv->rx,
+			.len = 1,
+			.cs_change = 1,
+		}, {
+			.tx_buf = &priv->tx,
+			.rx_buf = &priv->rx,
+			.len = 1,
+		},
+	};
+	u8 status;
+	int ret;
 
-	ret = spi_sync_transfer(spi, xfers, 2);
+	priv->tx = MPF_SPI_READ_STATUS;
+
+	ret = spi_sync_transfer(priv->spi, xfers, 2);
+	if (ret)
+		return ret;
+
+	status = priv->rx;
 
 	if ((status & MPF_STATUS_SPI_VIOLATION) ||
 	    (status & MPF_STATUS_SPI_ERROR))
-		ret = -EIO;
+		return -EIO;
 
-	return ret ? : status;
+	return status;
 }
 
 static enum fpga_mgr_states mpf_ops_state(struct fpga_manager *mgr)
 {
 	struct mpf_priv *priv = mgr->priv;
-	struct spi_device *spi;
 	bool program_mode;
 	int status;
 
-	spi = priv->spi;
 	program_mode = priv->program_mode;
-	status = mpf_read_status(spi);
+	status = mpf_read_status(priv);
 
 	if (!program_mode && !status)
 		return FPGA_MGR_STATE_OPERATING;
@@ -185,52 +195,53 @@ static int mpf_ops_parse_header(struct fpga_manager *mgr,
 	return 0;
 }
 
-/* Poll HW status until busy bit is cleared and mask bits are set. */
-static int mpf_poll_status(struct spi_device *spi, u8 mask)
+static int mpf_poll_status(struct mpf_priv *priv, u8 mask)
 {
-	int status, retries = MPF_STATUS_POLL_RETRIES;
-
-	while (retries--) {
-		status = mpf_read_status(spi);
-		if (status < 0)
-			return status;
+	int ret, status;
 
-		if (status & MPF_STATUS_BUSY)
-			continue;
-
-		if (!mask || (status & mask))
-			return status;
-	}
+	/*
+	 * Busy poll HW status. Polling stops if any of the following
+	 * conditions are met:
+	 *  - timeout is reached
+	 *  - mpf_read_status() returns an error
+	 *  - busy bit is cleared AND mask bits are set
+	 */
+	ret = read_poll_timeout(mpf_read_status, status,
+				(status < 0) ||
+				((status & (MPF_STATUS_BUSY | mask)) == mask),
+				0, MPF_STATUS_POLL_TIMEOUT, false, priv);
+	if (ret < 0)
+		return ret;
 
-	return -EBUSY;
+	return status;
 }
 
-static int mpf_spi_write(struct spi_device *spi, const void *buf, size_t buf_size)
+static int mpf_spi_write(struct mpf_priv *priv, const void *buf, size_t buf_size)
 {
-	int status = mpf_poll_status(spi, 0);
+	int status = mpf_poll_status(priv, 0);
 
 	if (status < 0)
 		return status;
 
-	return spi_write(spi, buf, buf_size);
+	return spi_write_then_read(priv->spi, buf, buf_size, NULL, 0);
 }
 
-static int mpf_spi_write_then_read(struct spi_device *spi,
+static int mpf_spi_write_then_read(struct mpf_priv *priv,
 				   const void *txbuf, size_t txbuf_size,
 				   void *rxbuf, size_t rxbuf_size)
 {
 	const u8 read_command[] = { MPF_SPI_READ_DATA };
 	int ret;
 
-	ret = mpf_spi_write(spi, txbuf, txbuf_size);
+	ret = mpf_spi_write(priv, txbuf, txbuf_size);
 	if (ret)
 		return ret;
 
-	ret = mpf_poll_status(spi, MPF_STATUS_READY);
+	ret = mpf_poll_status(priv, MPF_STATUS_READY);
 	if (ret < 0)
 		return ret;
 
-	return spi_write_then_read(spi, read_command, sizeof(read_command),
+	return spi_write_then_read(priv->spi, read_command, sizeof(read_command),
 				   rxbuf, rxbuf_size);
 }
 
@@ -242,7 +253,6 @@ static int mpf_ops_write_init(struct fpga_manager *mgr,
 	const u8 isc_en_command[] = { MPF_SPI_ISC_ENABLE };
 	struct mpf_priv *priv = mgr->priv;
 	struct device *dev = &mgr->dev;
-	struct spi_device *spi;
 	u32 isc_ret = 0;
 	int ret;
 
@@ -251,9 +261,7 @@ static int mpf_ops_write_init(struct fpga_manager *mgr,
 		return -EOPNOTSUPP;
 	}
 
-	spi = priv->spi;
-
-	ret = mpf_spi_write_then_read(spi, isc_en_command, sizeof(isc_en_command),
+	ret = mpf_spi_write_then_read(priv, isc_en_command, sizeof(isc_en_command),
 				      &isc_ret, sizeof(isc_ret));
 	if (ret || isc_ret) {
 		dev_err(dev, "Failed to enable ISC: spi_ret %d, isc_ret %u\n",
@@ -261,7 +269,7 @@ static int mpf_ops_write_init(struct fpga_manager *mgr,
 		return -EFAULT;
 	}
 
-	ret = mpf_spi_write(spi, program_mode, sizeof(program_mode));
+	ret = mpf_spi_write(priv, program_mode, sizeof(program_mode));
 	if (ret) {
 		dev_err(dev, "Failed to enter program mode: %d\n", ret);
 		return ret;
@@ -272,13 +280,32 @@ static int mpf_ops_write_init(struct fpga_manager *mgr,
 	return 0;
 }
 
+static int mpf_spi_frame_write(struct mpf_priv *priv, const char *buf)
+{
+	struct spi_transfer xfers[2] = {
+		{
+			.tx_buf = &priv->tx,
+			.len = 1,
+		}, {
+			.tx_buf = buf,
+			.len = MPF_SPI_FRAME_SIZE,
+		},
+	};
+	int ret;
+
+	ret = mpf_poll_status(priv, 0);
+	if (ret < 0)
+		return ret;
+
+	priv->tx = MPF_SPI_FRAME;
+
+	return spi_sync_transfer(priv->spi, xfers, ARRAY_SIZE(xfers));
+}
+
 static int mpf_ops_write(struct fpga_manager *mgr, const char *buf, size_t count)
 {
-	u8 spi_frame_command[] = { MPF_SPI_FRAME };
-	struct spi_transfer xfers[2] = { 0 };
 	struct mpf_priv *priv = mgr->priv;
 	struct device *dev = &mgr->dev;
-	struct spi_device *spi;
 	int ret, i;
 
 	if (count % MPF_SPI_FRAME_SIZE) {
@@ -287,19 +314,8 @@ static int mpf_ops_write(struct fpga_manager *mgr, const char *buf, size_t count
 		return -EINVAL;
 	}
 
-	spi = priv->spi;
-
-	xfers[0].tx_buf = spi_frame_command;
-	xfers[0].len = sizeof(spi_frame_command);
-
 	for (i = 0; i < count / MPF_SPI_FRAME_SIZE; i++) {
-		xfers[1].tx_buf = buf + i * MPF_SPI_FRAME_SIZE;
-		xfers[1].len = MPF_SPI_FRAME_SIZE;
-
-		ret = mpf_poll_status(spi, 0);
-		if (ret >= 0)
-			ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));
-
+		ret = mpf_spi_frame_write(priv, buf + i * MPF_SPI_FRAME_SIZE);
 		if (ret) {
 			dev_err(dev, "Failed to write bitstream frame %d/%zu\n",
 				i, count / MPF_SPI_FRAME_SIZE);
@@ -317,12 +333,9 @@ static int mpf_ops_write_complete(struct fpga_manager *mgr,
 	const u8 release_command[] = { MPF_SPI_RELEASE };
 	struct mpf_priv *priv = mgr->priv;
 	struct device *dev = &mgr->dev;
-	struct spi_device *spi;
 	int ret;
 
-	spi = priv->spi;
-
-	ret = mpf_spi_write(spi, isc_dis_command, sizeof(isc_dis_command));
+	ret = mpf_spi_write(priv, isc_dis_command, sizeof(isc_dis_command));
 	if (ret) {
 		dev_err(dev, "Failed to disable ISC: %d\n", ret);
 		return ret;
@@ -330,7 +343,7 @@ static int mpf_ops_write_complete(struct fpga_manager *mgr,
 
 	usleep_range(1000, 2000);
 
-	ret = mpf_spi_write(spi, release_command, sizeof(release_command));
+	ret = mpf_spi_write(priv, release_command, sizeof(release_command));
 	if (ret) {
 		dev_err(dev, "Failed to exit program mode: %d\n", ret);
 		return ret;