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-rw-r--r--drivers/spi/spi-xilinx.c298
1 files changed, 163 insertions, 135 deletions
diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 79bd84f43430..133f53a9c1d4 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) {
generated by cgit v1.2.3 (git 2.39.0) at 2024-10-30 12:19:14 +0300