1 files changed, 118 insertions, 88 deletions

diff --git a/drivers/staging/mt7621-spi/spi-mt7621.c b/drivers/staging/mt7621-spi/spi-mt7621.c
index 37f299080410..d045b5568e0f 100644
--- a/drivers/staging/mt7621-spi/spi-mt7621.c
+++ b/drivers/staging/mt7621-spi/spi-mt7621.c
@@ -55,7 +55,8 @@
 #define MT7621_CPOL		BIT(4)
 #define MT7621_LSB_FIRST	BIT(3)
 
-#define RT2880_SPI_MODE_BITS	(SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_CS_HIGH)
+#define RT2880_SPI_MODE_BITS	(SPI_CPOL | SPI_CPHA |		\
+				 SPI_LSB_FIRST | SPI_CS_HIGH)
 
 struct mt7621_spi;
 
@@ -65,6 +66,7 @@ struct mt7621_spi {
 	unsigned int		sys_freq;
 	unsigned int		speed;
 	struct clk		*clk;
+	int			pending_write;
 
 	struct mt7621_spi_ops	*ops;
 };
@@ -96,6 +98,7 @@ static void mt7621_spi_reset(struct mt7621_spi *rs, int duplex)
 		master &= ~(1 << 10);
 
 	mt7621_spi_write(rs, MT7621_SPI_MASTER, master);
+	rs->pending_write = 0;
 }
 
 static void mt7621_spi_set_cs(struct spi_device *spi, int enable)
@@ -104,7 +107,7 @@ static void mt7621_spi_set_cs(struct spi_device *spi, int enable)
 	int cs = spi->chip_select;
 	u32 polar = 0;
 
-        mt7621_spi_reset(rs, cs);
+	mt7621_spi_reset(rs, cs);
 	if (enable)
 		polar = BIT(cs);
 	mt7621_spi_write(rs, MT7621_SPI_POLAR, polar);
@@ -137,36 +140,34 @@ static int mt7621_spi_prepare(struct spi_device *spi, unsigned int speed)
 		reg |= MT7621_LSB_FIRST;
 
 	reg &= ~(MT7621_CPHA | MT7621_CPOL);
-	switch(spi->mode & (SPI_CPOL | SPI_CPHA)) {
-		case SPI_MODE_0:
-			break;
-		case SPI_MODE_1:
-			reg |= MT7621_CPHA;
-			break;
-		case SPI_MODE_2:
-			reg |= MT7621_CPOL;
-			break;
-		case SPI_MODE_3:
-			reg |= MT7621_CPOL | MT7621_CPHA;
-			break;
+	switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
+	case SPI_MODE_0:
+		break;
+	case SPI_MODE_1:
+		reg |= MT7621_CPHA;
+		break;
+	case SPI_MODE_2:
+		reg |= MT7621_CPOL;
+		break;
+	case SPI_MODE_3:
+		reg |= MT7621_CPOL | MT7621_CPHA;
+		break;
 	}
 	mt7621_spi_write(rs, MT7621_SPI_MASTER, reg);
 
 	return 0;
 }
 
-static inline int mt7621_spi_wait_till_ready(struct spi_device *spi)
+static inline int mt7621_spi_wait_till_ready(struct mt7621_spi *rs)
 {
-	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
 	int i;
 
 	for (i = 0; i < RALINK_SPI_WAIT_MAX_LOOP; i++) {
 		u32 status;
 
 		status = mt7621_spi_read(rs, MT7621_SPI_TRANS);
-		if ((status & SPITRANS_BUSY) == 0) {
+		if ((status & SPITRANS_BUSY) == 0)
 			return 0;
-		}
 		cpu_relax();
 		udelay(1);
 	}
@@ -174,90 +175,124 @@ static inline int mt7621_spi_wait_till_ready(struct spi_device *spi)
 	return -ETIMEDOUT;
 }
 
-static int mt7621_spi_transfer_half_duplex(struct spi_master *master,
-					   struct spi_message *m)
+static void mt7621_spi_read_half_duplex(struct mt7621_spi *rs,
+					int rx_len, u8 *buf)
 {
-	struct mt7621_spi *rs = spi_master_get_devdata(master);
-	struct spi_device *spi = m->spi;
-	unsigned int speed = spi->max_speed_hz;
-	struct spi_transfer *t = NULL;
-	int status = 0;
-	int i, len = 0;
-	int rx_len = 0;
-	u32 data[9] = { 0 };
-	u32 val;
+	/* Combine with any pending write, and perform one or
+	 * more half-duplex transactions reading 'len' bytes.
+	 * Data to be written is already in MT7621_SPI_DATA*
+	 */
+	int tx_len = rs->pending_write;
 
-	mt7621_spi_wait_till_ready(spi);
+	rs->pending_write = 0;
 
-	list_for_each_entry(t, &m->transfers, transfer_list) {
-		const u8 *buf = t->tx_buf;
+	while (rx_len || tx_len) {
+		int i;
+		u32 val = (min(tx_len, 4) * 8) << 24;
+		int rx = min(rx_len, 32);
 
-		if (t->rx_buf)
-			rx_len += t->len;
+		if (tx_len > 4)
+			val |= (tx_len - 4) * 8;
+		val |= (rx * 8) << 12;
+		mt7621_spi_write(rs, MT7621_SPI_MOREBUF, val);
 
-		if (!buf)
-			continue;
+		tx_len = 0;
 
-		if (t->speed_hz < speed)
-			speed = t->speed_hz;
+		val = mt7621_spi_read(rs, MT7621_SPI_TRANS);
+		val |= SPI_CTL_START;
+		mt7621_spi_write(rs, MT7621_SPI_TRANS, val);
 
-		if (WARN_ON(len + t->len > 36)) {
-			status = -EIO;
-			goto msg_done;
-		}
+		mt7621_spi_wait_till_ready(rs);
 
-		for (i = 0; i < t->len; i++, len++)
-			data[len / 4] |= buf[i] << (8 * (len & 3));
+		for (i = 0; i < rx; i++) {
+			if ((i % 4) == 0)
+				val = mt7621_spi_read(rs, MT7621_SPI_DATA0 + i);
+			*buf++ = val & 0xff;
+			val >>= 8;
+		}
+		rx_len -= i;
 	}
+}
 
-	if (WARN_ON(rx_len > 32)) {
-		status = -EIO;
-		goto msg_done;
-	}
+static inline void mt7621_spi_flush(struct mt7621_spi *rs)
+{
+	mt7621_spi_read_half_duplex(rs, 0, NULL);
+}
 
-	if (mt7621_spi_prepare(spi, speed)) {
-		status = -EIO;
-		goto msg_done;
+static void mt7621_spi_write_half_duplex(struct mt7621_spi *rs,
+					 int tx_len, const u8 *buf)
+{
+	int val = 0;
+	int len = rs->pending_write;
+
+	if (len & 3) {
+		val = mt7621_spi_read(rs, MT7621_SPI_OPCODE + (len & ~3));
+		if (len < 4) {
+			val <<= (4 - len) * 8;
+			val = swab32(val);
+		}
 	}
-	data[0] = swab32(data[0]);
-	if (len < 4)
-		data[0] >>= (4 - len) * 8;
-
-	for (i = 0; i < len; i += 4)
-		mt7621_spi_write(rs, MT7621_SPI_OPCODE + i, data[i / 4]);
-
-	val = (min_t(int, len, 4) * 8) << 24;
-	if (len > 4)
-		val |= (len - 4) * 8;
-	val |= (rx_len * 8) << 12;
-	mt7621_spi_write(rs, MT7621_SPI_MOREBUF, val);
 
-	mt7621_spi_set_cs(spi, 1);
+	while (tx_len > 0) {
+		if (len >= 36) {
+			rs->pending_write = len;
+			mt7621_spi_flush(rs);
+			len = 0;
+		}
 
-	val = mt7621_spi_read(rs, MT7621_SPI_TRANS);
-	val |= SPI_CTL_START;
-	mt7621_spi_write(rs, MT7621_SPI_TRANS, val);
+		val |= *buf++ << (8 * (len & 3));
+		len++;
+		if ((len & 3) == 0) {
+			if (len == 4)
+				/* The byte-order of the opcode is weird! */
+				val = swab32(val);
+			mt7621_spi_write(rs, MT7621_SPI_OPCODE + len - 4, val);
+			val = 0;
+		}
+		tx_len -= 1;
+	}
+	if (len & 3) {
+		if (len < 4) {
+			val = swab32(val);
+			val >>= (4 - len) * 8;
+		}
+		mt7621_spi_write(rs, MT7621_SPI_OPCODE + (len & ~3), val);
+	}
+	rs->pending_write = len;
+}
 
-	mt7621_spi_wait_till_ready(spi);
+static int mt7621_spi_transfer_half_duplex(struct spi_master *master,
+					   struct spi_message *m)
+{
+	struct mt7621_spi *rs = spi_master_get_devdata(master);
+	struct spi_device *spi = m->spi;
+	unsigned int speed = spi->max_speed_hz;
+	struct spi_transfer *t = NULL;
+	int status = 0;
 
-	mt7621_spi_set_cs(spi, 0);
+	mt7621_spi_wait_till_ready(rs);
 
-	for (i = 0; i < rx_len; i += 4)
-		data[i / 4] = mt7621_spi_read(rs, MT7621_SPI_DATA0 + i);
+	list_for_each_entry(t, &m->transfers, transfer_list)
+		if (t->speed_hz < speed)
+			speed = t->speed_hz;
 
-	m->actual_length = len + rx_len;
+	if (mt7621_spi_prepare(spi, speed)) {
+		status = -EIO;
+		goto msg_done;
+	}
 
-	len = 0;
+	mt7621_spi_set_cs(spi, 1);
+	m->actual_length = 0;
 	list_for_each_entry(t, &m->transfers, transfer_list) {
-		u8 *buf = t->rx_buf;
-
-		if (!buf)
-			continue;
-
-		for (i = 0; i < t->len; i++, len++)
-			buf[i] = data[len / 4] >> (8 * (len & 3));
+		if (t->rx_buf)
+			mt7621_spi_read_half_duplex(rs, t->len, t->rx_buf);
+		else if (t->tx_buf)
+			mt7621_spi_write_half_duplex(rs, t->len, t->tx_buf);
+		m->actual_length += t->len;
 	}
+	mt7621_spi_flush(rs);
 
+	mt7621_spi_set_cs(spi, 0);
 msg_done:
 	m->status = status;
 	spi_finalize_current_message(master);
@@ -278,7 +313,7 @@ static int mt7621_spi_transfer_full_duplex(struct spi_master *master,
 	u32 data[9] = { 0 };
 	u32 val = 0;
 
-	mt7621_spi_wait_till_ready(spi);
+	mt7621_spi_wait_till_ready(rs);
 
 	list_for_each_entry(t, &m->transfers, transfer_list) {
 		const u8 *buf = t->tx_buf;
@@ -323,7 +358,7 @@ static int mt7621_spi_transfer_full_duplex(struct spi_master *master,
 	val |= SPI_CTL_START;
 	mt7621_spi_write(rs, MT7621_SPI_TRANS, val);
 
-	mt7621_spi_wait_till_ready(spi);
+	mt7621_spi_wait_till_ready(rs);
 
 	mt7621_spi_set_cs(spi, 0);
 
@@ -384,11 +419,6 @@ static const struct of_device_id mt7621_spi_match[] = {
 };
 MODULE_DEVICE_TABLE(of, mt7621_spi_match);
 
-static size_t max_transfer_size(struct spi_device *spi)
-{
-	return 32;
-}
-
 static int mt7621_spi_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *match;
@@ -434,7 +464,6 @@ static int mt7621_spi_probe(struct platform_device *pdev)
 	master->bits_per_word_mask = SPI_BPW_MASK(8);
 	master->dev.of_node = pdev->dev.of_node;
 	master->num_chipselect = 2;
-	master->max_transfer_size = max_transfer_size;
 
 	dev_set_drvdata(&pdev->dev, master);
 
@@ -444,6 +473,7 @@ static int mt7621_spi_probe(struct platform_device *pdev)
 	rs->master = master;
 	rs->sys_freq = clk_get_rate(rs->clk);
 	rs->ops = ops;
+	rs->pending_write = 0;
 	dev_info(&pdev->dev, "sys_freq: %u\n", rs->sys_freq);
 
 	device_reset(&pdev->dev);