Merge tag 'spi-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi

Pull spi updates from Mark Brown:
 "The major highlight this release is a refactoring of the core to allow
  us to run synchronous transfers in the context of the caller when
  there is no contention for the bus.  This improves performance in the
  very common case by eliminating context switches and reducing the
  number of hardware setup and teardown operations we need to perform.

  Other changes:

   - New drivers for DLN-2 USB-SPI adapter and ST SPI controllers.

   - A big round of cleanups, performance and feature improvements for
     the xilinx driver from Ricardo Ribalda Delgado.

   - A wide range of smaller cleanups, fixes and feature improvements
     throughout the subsystem"

* tag 'spi-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (68 commits)
  spi: mxs: cleanup wait_for_completion return handling
  spi: ti-qspi: cleanup wait_for_completion return handling
  spi: spi-imx: cleanup wait_for_completion handling
  spi: sh-msiof: cleanup wait_for_completion return handling
  spi: match var type to return type of wait_for_completion
  spi: spi-pxa2xx: only include mach/dma.h for legacy DMA
  spi: atmel: cleanup wait_for_completion return handling
  spi: fsl-dspi: Remove possible memory leak of 'chip'
  spi: sh-msiof: Update calculation of frequency dividing
  spi: spidev: Convert buf pointers for 32-bit compat SPI_IOC_MESSAGE(n)
  spi/xilinx: Fix access invalid memory on xilinx_spi_tx
  spi: Revert "spi/xilinx: Remove iowrite/ioread wrappers"
  spi/xilinx: Check number of slaves range
  spi/xilinx: Use polling mode on small transfers
  spi/xilinx: Remove remaining_words driver data variable
  spi/xilinx: Remove iowrite/ioread wrappers
  spi/xilinx: Convert bits_per_word in bytes_per_word
  spi/xilinx: Convert remainding_bytes in remaining words
  spi/xilinx: Make spi_tx and spi_rx simmetric
  spi/xilinx: Remove rx_fn and tx_fn pointer
  ...

1 files changed, 163 insertions, 135 deletions

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 79bd84f4343..133f53a9c1d 100644
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -22,6 +22,8 @@
 #include <linux/spi/xilinx_spi.h>
 #include <linux/io.h>
 
+#define XILINX_SPI_MAX_CS	32
+
 #define XILINX_SPI_NAME "xilinx_spi"
 
 /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
@@ -34,7 +36,8 @@
 #define XSPI_CR_MASTER_MODE	0x04
 #define XSPI_CR_CPOL		0x08
 #define XSPI_CR_CPHA		0x10
-#define XSPI_CR_MODE_MASK	(XSPI_CR_CPHA | XSPI_CR_CPOL)
+#define XSPI_CR_MODE_MASK	(XSPI_CR_CPHA | XSPI_CR_CPOL | \
+				 XSPI_CR_LSB_FIRST | XSPI_CR_LOOP)
 #define XSPI_CR_TXFIFO_RESET	0x20
 #define XSPI_CR_RXFIFO_RESET	0x40
 #define XSPI_CR_MANUAL_SSELECT	0x80
@@ -85,12 +88,11 @@ struct xilinx_spi {
 
 	u8 *rx_ptr;		/* pointer in the Tx buffer */
 	const u8 *tx_ptr;	/* pointer in the Rx buffer */
-	int remaining_bytes;	/* the number of bytes left to transfer */
-	u8 bits_per_word;
+	u8 bytes_per_word;
+	int buffer_size;	/* buffer size in words */
+	u32 cs_inactive;	/* Level of the CS pins when inactive*/
 	unsigned int (*read_fn)(void __iomem *);
 	void (*write_fn)(u32, void __iomem *);
-	void (*tx_fn)(struct xilinx_spi *);
-	void (*rx_fn)(struct xilinx_spi *);
 };
 
 static void xspi_write32(u32 val, void __iomem *addr)
@@ -113,49 +115,51 @@ static unsigned int xspi_read32_be(void __iomem *addr)
 	return ioread32be(addr);
 }
 
-static void xspi_tx8(struct xilinx_spi *xspi)
+static void xilinx_spi_tx(struct xilinx_spi *xspi)
 {
-	xspi->write_fn(*xspi->tx_ptr, xspi->regs + XSPI_TXD_OFFSET);
-	xspi->tx_ptr++;
-}
-
-static void xspi_tx16(struct xilinx_spi *xspi)
-{
-	xspi->write_fn(*(u16 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
-	xspi->tx_ptr += 2;
-}
+	u32 data = 0;
 
-static void xspi_tx32(struct xilinx_spi *xspi)
-{
-	xspi->write_fn(*(u32 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
-	xspi->tx_ptr += 4;
-}
-
-static void xspi_rx8(struct xilinx_spi *xspi)
-{
-	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
-	if (xspi->rx_ptr) {
-		*xspi->rx_ptr = data & 0xff;
-		xspi->rx_ptr++;
+	if (!xspi->tx_ptr) {
+		xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
+		return;
 	}
-}
 
-static void xspi_rx16(struct xilinx_spi *xspi)
-{
-	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
-	if (xspi->rx_ptr) {
-		*(u16 *)(xspi->rx_ptr) = data & 0xffff;
-		xspi->rx_ptr += 2;
+	switch (xspi->bytes_per_word) {
+	case 1:
+		data = *(u8 *)(xspi->tx_ptr);
+		break;
+	case 2:
+		data = *(u16 *)(xspi->tx_ptr);
+		break;
+	case 4:
+		data = *(u32 *)(xspi->tx_ptr);
+		break;
 	}
+
+	xspi->write_fn(data, xspi->regs + XSPI_TXD_OFFSET);
+	xspi->tx_ptr += xspi->bytes_per_word;
 }
 
-static void xspi_rx32(struct xilinx_spi *xspi)
+static void xilinx_spi_rx(struct xilinx_spi *xspi)
 {
 	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
-	if (xspi->rx_ptr) {
+
+	if (!xspi->rx_ptr)
+		return;
+
+	switch (xspi->bytes_per_word) {
+	case 1:
+		*(u8 *)(xspi->rx_ptr) = data;
+		break;
+	case 2:
+		*(u16 *)(xspi->rx_ptr) = data;
+		break;
+	case 4:
 		*(u32 *)(xspi->rx_ptr) = data;
-		xspi->rx_ptr += 4;
+		break;
 	}
+
+	xspi->rx_ptr += xspi->bytes_per_word;
 }
 
 static void xspi_init_hw(struct xilinx_spi *xspi)
@@ -165,46 +169,56 @@ static void xspi_init_hw(struct xilinx_spi *xspi)
 	/* Reset the SPI device */
 	xspi->write_fn(XIPIF_V123B_RESET_MASK,
 		regs_base + XIPIF_V123B_RESETR_OFFSET);
-	/* Disable all the interrupts just in case */
-	xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
-	/* Enable the global IPIF interrupt */
-	xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
-		regs_base + XIPIF_V123B_DGIER_OFFSET);
+	/* Enable the transmit empty interrupt, which we use to determine
+	 * progress on the transmission.
+	 */
+	xspi->write_fn(XSPI_INTR_TX_EMPTY,
+			regs_base + XIPIF_V123B_IIER_OFFSET);
+	/* Disable the global IPIF interrupt */
+	xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
 	/* Deselect the slave on the SPI bus */
 	xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
 	/* Disable the transmitter, enable Manual Slave Select Assertion,
 	 * put SPI controller into master mode, and enable it */
-	xspi->write_fn(XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT |
-		XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET |
-		XSPI_CR_RXFIFO_RESET, regs_base + XSPI_CR_OFFSET);
+	xspi->write_fn(XSPI_CR_MANUAL_SSELECT |	XSPI_CR_MASTER_MODE |
+		XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET |	XSPI_CR_RXFIFO_RESET,
+		regs_base + XSPI_CR_OFFSET);
 }
 
 static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
 {
 	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+	u16 cr;
+	u32 cs;
 
 	if (is_on == BITBANG_CS_INACTIVE) {
 		/* Deselect the slave on the SPI bus */
-		xspi->write_fn(0xffff, xspi->regs + XSPI_SSR_OFFSET);
-	} else if (is_on == BITBANG_CS_ACTIVE) {
-		/* Set the SPI clock phase and polarity */
-		u16 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)
-			 & ~XSPI_CR_MODE_MASK;
-		if (spi->mode & SPI_CPHA)
-			cr |= XSPI_CR_CPHA;
-		if (spi->mode & SPI_CPOL)
-			cr |= XSPI_CR_CPOL;
-		xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
-
-		/* We do not check spi->max_speed_hz here as the SPI clock
-		 * frequency is not software programmable (the IP block design
-		 * parameter)
-		 */
-
-		/* Activate the chip select */
-		xspi->write_fn(~(0x0001 << spi->chip_select),
-			xspi->regs + XSPI_SSR_OFFSET);
+		xspi->write_fn(xspi->cs_inactive, xspi->regs + XSPI_SSR_OFFSET);
+		return;
 	}
+
+	/* Set the SPI clock phase and polarity */
+	cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)	& ~XSPI_CR_MODE_MASK;
+	if (spi->mode & SPI_CPHA)
+		cr |= XSPI_CR_CPHA;
+	if (spi->mode & SPI_CPOL)
+		cr |= XSPI_CR_CPOL;
+	if (spi->mode & SPI_LSB_FIRST)
+		cr |= XSPI_CR_LSB_FIRST;
+	if (spi->mode & SPI_LOOP)
+		cr |= XSPI_CR_LOOP;
+	xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
+
+	/* We do not check spi->max_speed_hz here as the SPI clock
+	 * frequency is not software programmable (the IP block design
+	 * parameter)
+	 */
+
+	cs = xspi->cs_inactive;
+	cs ^= BIT(spi->chip_select);
+
+	/* Activate the chip select */
+	xspi->write_fn(cs, xspi->regs + XSPI_SSR_OFFSET);
 }
 
 /* spi_bitbang requires custom setup_transfer() to be defined if there is a
@@ -213,85 +227,85 @@ static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
 static int xilinx_spi_setup_transfer(struct spi_device *spi,
 		struct spi_transfer *t)
 {
-	return 0;
-}
+	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
 
-static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi)
-{
-	u8 sr;
+	if (spi->mode & SPI_CS_HIGH)
+		xspi->cs_inactive &= ~BIT(spi->chip_select);
+	else
+		xspi->cs_inactive |= BIT(spi->chip_select);
 
-	/* Fill the Tx FIFO with as many bytes as possible */
-	sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
-	while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) {
-		if (xspi->tx_ptr)
-			xspi->tx_fn(xspi);
-		else
-			xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
-		xspi->remaining_bytes -= xspi->bits_per_word / 8;
-		sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
-	}
+	return 0;
 }
 
 static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
 {
 	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
-	u32 ipif_ier;
+	int remaining_words;	/* the number of words left to transfer */
+	bool use_irq = false;
+	u16 cr = 0;
 
 	/* We get here with transmitter inhibited */
 
 	xspi->tx_ptr = t->tx_buf;
 	xspi->rx_ptr = t->rx_buf;
-	xspi->remaining_bytes = t->len;
+	remaining_words = t->len / xspi->bytes_per_word;
 	reinit_completion(&xspi->done);
 
+	if (xspi->irq >= 0 &&  remaining_words > xspi->buffer_size) {
+		use_irq = true;
+		xspi->write_fn(XSPI_INTR_TX_EMPTY,
+				xspi->regs + XIPIF_V123B_IISR_OFFSET);
+		/* Enable the global IPIF interrupt */
+		xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
+				xspi->regs + XIPIF_V123B_DGIER_OFFSET);
+		/* Inhibit irq to avoid spurious irqs on tx_empty*/
+		cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
+		xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
+			       xspi->regs + XSPI_CR_OFFSET);
+	}
 
-	/* Enable the transmit empty interrupt, which we use to determine
-	 * progress on the transmission.
-	 */
-	ipif_ier = xspi->read_fn(xspi->regs + XIPIF_V123B_IIER_OFFSET);
-	xspi->write_fn(ipif_ier | XSPI_INTR_TX_EMPTY,
-		xspi->regs + XIPIF_V123B_IIER_OFFSET);
+	while (remaining_words) {
+		int n_words, tx_words, rx_words;
 
-	for (;;) {
-		u16 cr;
-		u8 sr;
+		n_words = min(remaining_words, xspi->buffer_size);
 
-		xilinx_spi_fill_tx_fifo(xspi);
+		tx_words = n_words;
+		while (tx_words--)
+			xilinx_spi_tx(xspi);
 
 		/* Start the transfer by not inhibiting the transmitter any
 		 * longer
 		 */
-		cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) &
-							~XSPI_CR_TRANS_INHIBIT;
-		xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
 
-		wait_for_completion(&xspi->done);
+		if (use_irq) {
+			xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
+			wait_for_completion(&xspi->done);
+		} else
+			while (!(xspi->read_fn(xspi->regs + XSPI_SR_OFFSET) &
+						XSPI_SR_TX_EMPTY_MASK))
+				;
 
 		/* A transmit has just completed. Process received data and
 		 * check for more data to transmit. Always inhibit the
 		 * transmitter while the Isr refills the transmit register/FIFO,
 		 * or make sure it is stopped if we're done.
 		 */
-		cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
-		xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
+		if (use_irq)
+			xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
 			       xspi->regs + XSPI_CR_OFFSET);
 
 		/* Read out all the data from the Rx FIFO */
-		sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
-		while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) {
-			xspi->rx_fn(xspi);
-			sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
-		}
-
-		/* See if there is more data to send */
-		if (xspi->remaining_bytes <= 0)
-			break;
+		rx_words = n_words;
+		while (rx_words--)
+			xilinx_spi_rx(xspi);
+
+		remaining_words -= n_words;
 	}
 
-	/* Disable the transmit empty interrupt */
-	xspi->write_fn(ipif_ier, xspi->regs + XIPIF_V123B_IIER_OFFSET);
+	if (use_irq)
+		xspi->write_fn(0, xspi->regs + XIPIF_V123B_DGIER_OFFSET);
 
-	return t->len - xspi->remaining_bytes;
+	return t->len;
 }
 
 
@@ -316,6 +330,28 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static int xilinx_spi_find_buffer_size(struct xilinx_spi *xspi)
+{
+	u8 sr;
+	int n_words = 0;
+
+	/*
+	 * Before the buffer_size detection we reset the core
+	 * to make sure we start with a clean state.
+	 */
+	xspi->write_fn(XIPIF_V123B_RESET_MASK,
+		xspi->regs + XIPIF_V123B_RESETR_OFFSET);
+
+	/* Fill the Tx FIFO with as many words as possible */
+	do {
+		xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
+		sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
+		n_words++;
+	} while (!(sr & XSPI_SR_TX_FULL_MASK));
+
+	return n_words;
+}
+
 static const struct of_device_id xilinx_spi_of_match[] = {
 	{ .compatible = "xlnx,xps-spi-2.00.a", },
 	{ .compatible = "xlnx,xps-spi-2.00.b", },
@@ -348,14 +384,21 @@ static int xilinx_spi_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	if (num_cs > XILINX_SPI_MAX_CS) {
+		dev_err(&pdev->dev, "Invalid number of spi slaves\n");
+		return -EINVAL;
+	}
+
 	master = spi_alloc_master(&pdev->dev, sizeof(struct xilinx_spi));
 	if (!master)
 		return -ENODEV;
 
 	/* the spi->mode bits understood by this driver: */
-	master->mode_bits = SPI_CPOL | SPI_CPHA;
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_LOOP |
+			    SPI_CS_HIGH;
 
 	xspi = spi_master_get_devdata(master);
+	xspi->cs_inactive = 0xffffffff;
 	xspi->bitbang.master = master;
 	xspi->bitbang.chipselect = xilinx_spi_chipselect;
 	xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
@@ -392,35 +435,20 @@ static int xilinx_spi_probe(struct platform_device *pdev)
 	}
 
 	master->bits_per_word_mask = SPI_BPW_MASK(bits_per_word);
-	xspi->bits_per_word = bits_per_word;
-	if (xspi->bits_per_word == 8) {
-		xspi->tx_fn = xspi_tx8;
-		xspi->rx_fn = xspi_rx8;
-	} else if (xspi->bits_per_word == 16) {
-		xspi->tx_fn = xspi_tx16;
-		xspi->rx_fn = xspi_rx16;
-	} else if (xspi->bits_per_word == 32) {
-		xspi->tx_fn = xspi_tx32;
-		xspi->rx_fn = xspi_rx32;
-	} else {
-		ret = -EINVAL;
-		goto put_master;
-	}
-
-	/* SPI controller initializations */
-	xspi_init_hw(xspi);
+	xspi->bytes_per_word = bits_per_word / 8;
+	xspi->buffer_size = xilinx_spi_find_buffer_size(xspi);
 
 	xspi->irq = platform_get_irq(pdev, 0);
-	if (xspi->irq < 0) {
-		ret = xspi->irq;
-		goto put_master;
+	if (xspi->irq >= 0) {
+		/* Register for SPI Interrupt */
+		ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
+				dev_name(&pdev->dev), xspi);
+		if (ret)
+			goto put_master;
 	}
 
-	/* Register for SPI Interrupt */
-	ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
-			       dev_name(&pdev->dev), xspi);
-	if (ret)
-		goto put_master;
+	/* SPI controller initializations */
+	xspi_init_hw(xspi);
 
 	ret = spi_bitbang_start(&xspi->bitbang);
 	if (ret) {