[PATCH 3/4] xilinx_spi: add support for the DS570 IP.
Grant Likely
grant.likely at secretlab.ca
Thu Nov 12 08:15:39 EST 2009
On Wed, Nov 11, 2009 at 7:39 AM, Richard Röjfors
<richard.rojfors at mocean-labs.com> wrote:
> This patch adds in support for the DS570 IP.
>
> It's register compatible with the DS464, but adds support for 8/16/32 SPI.
>
> Signed-off-by: Richard Röjfors <richard.rojfors at mocean-labs.com>
Needs some changes. Comments below....
> ---
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index 9667650..b956284 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -235,7 +235,7 @@ config SPI_TXX9
> SPI driver for Toshiba TXx9 MIPS SoCs
>
> config SPI_XILINX
> - tristate "Xilinx SPI controller"
> + tristate "Xilinx SPI controller common module"
> depends on HAS_IOMEM && EXPERIMENTAL
> select SPI_BITBANG
> help
> @@ -244,6 +244,8 @@ config SPI_XILINX
> See the "OPB Serial Peripheral Interface (SPI) (v1.00e)"
> Product Specification document (DS464) for hardware details.
>
> + Or for the DS570, see "XPS Serial Peripheral Interface (SPI) (v2.00b)"
> +
> config SPI_XILINX_OF
> tristate "Xilinx SPI controller OF device"
> depends on SPI_XILINX && (XILINX_VIRTEX || MICROBLAZE)
> diff --git a/drivers/spi/xilinx_spi.c b/drivers/spi/xilinx_spi.c
> index b00dabc..ae744ba 100644
> --- a/drivers/spi/xilinx_spi.c
> +++ b/drivers/spi/xilinx_spi.c
> @@ -24,7 +24,7 @@
> /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
> * Product Specification", DS464
> */
> -#define XSPI_CR_OFFSET 0x60 /* 16-bit Control Register */
> +#define XSPI_CR_OFFSET 0x60 /* Control Register */
>
> #define XSPI_CR_ENABLE 0x02
> #define XSPI_CR_MASTER_MODE 0x04
> @@ -35,8 +35,9 @@
> #define XSPI_CR_RXFIFO_RESET 0x40
> #define XSPI_CR_MANUAL_SSELECT 0x80
> #define XSPI_CR_TRANS_INHIBIT 0x100
> +#define XSPI_CR_LSB_FIRST 0x200
>
> -#define XSPI_SR_OFFSET 0x64 /* 8-bit Status Register */
> +#define XSPI_SR_OFFSET 0x64 /* Status Register */
>
> #define XSPI_SR_RX_EMPTY_MASK 0x01 /* Receive FIFO is empty */
> #define XSPI_SR_RX_FULL_MASK 0x02 /* Receive FIFO is full */
> @@ -44,8 +45,8 @@
> #define XSPI_SR_TX_FULL_MASK 0x08 /* Transmit FIFO is full */
> #define XSPI_SR_MODE_FAULT_MASK 0x10 /* Mode fault error */
>
> -#define XSPI_TXD_OFFSET 0x68 /* 8-bit Data Transmit Register */
> -#define XSPI_RXD_OFFSET 0x6c /* 8-bit Data Receive Register */
> +#define XSPI_TXD_OFFSET 0x68 /* Data Transmit Register */
> +#define XSPI_RXD_OFFSET 0x6c /* Data Receive Register */
>
> #define XSPI_SSR_OFFSET 0x70 /* 32-bit Slave Select Register */
>
> @@ -65,6 +66,7 @@
> #define XSPI_INTR_TX_UNDERRUN 0x08 /* TxFIFO was underrun */
> #define XSPI_INTR_RX_FULL 0x10 /* RxFIFO is full */
> #define XSPI_INTR_RX_OVERRUN 0x20 /* RxFIFO was overrun */
> +#define XSPI_INTR_TX_HALF_EMPTY 0x40 /* TxFIFO is half empty */
>
> #define XIPIF_V123B_RESETR_OFFSET 0x40 /* IPIF reset register */
> #define XIPIF_V123B_RESET_MASK 0x0a /* the value to write */
> @@ -86,6 +88,7 @@ struct xilinx_spi {
> bool big_endian; /* The device could be accessed big or little
> * endian
> */
> + u8 bits_per_word;
> };
>
> /* to follow are some functions that does little of big endian read and
> @@ -146,8 +149,9 @@ static void xspi_init_hw(struct xilinx_spi *xspi)
> /* Disable the transmitter, enable Manual Slave Select Assertion,
> * put SPI controller into master mode, and enable it */
> xspi_write16(xspi, XSPI_CR_OFFSET,
> - XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT
> - | XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE);
> + XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT |
> + XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET |
> + XSPI_CR_RXFIFO_RESET);
> }
>
> static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
> @@ -179,17 +183,20 @@ static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
>
> /* spi_bitbang requires custom setup_transfer() to be defined if there is a
> * custom txrx_bufs(). We have nothing to setup here as the SPI IP block
> - * supports just 8 bits per word, and SPI clock can't be changed in software.
> - * Check for 8 bits per word. Chip select delay calculations could be
> + * supports 8 or 16 bits per word, which can not be changed in software.
> + * SPI clock can't be changed in software.
> + * Check for correct bits per word. Chip select delay calculations could be
> * added here as soon as bitbang_work() can be made aware of the delay value.
> */
> static int xilinx_spi_setup_transfer(struct spi_device *spi,
> - struct spi_transfer *t)
> + struct spi_transfer *t)
> {
> u8 bits_per_word;
> + struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
>
> - bits_per_word = (t) ? t->bits_per_word : spi->bits_per_word;
> - if (bits_per_word != 8) {
> + bits_per_word = (t->bits_per_word) ? t->bits_per_word :
> + spi->bits_per_word;
> + if (bits_per_word != xspi->bits_per_word) {
> dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
> __func__, bits_per_word);
> return -EINVAL;
> @@ -200,33 +207,49 @@ static int xilinx_spi_setup_transfer(struct spi_device *spi,
>
> static int xilinx_spi_setup(struct spi_device *spi)
> {
> - struct spi_bitbang *bitbang;
> - struct xilinx_spi *xspi;
> - int retval;
> -
> - xspi = spi_master_get_devdata(spi->master);
> - bitbang = &xspi->bitbang;
> -
> - retval = xilinx_spi_setup_transfer(spi, NULL);
> - if (retval < 0)
> - return retval;
> -
> + /* always return 0, we can not check the number of bits.
> + * There are cases when SPI setup is called before any driver is
> + * there, in that case the SPI core defaults to 8 bits, which we
> + * do not support in some cases. But if we return an error, the
> + * SPI device would not be registered and no driver can get hold of it
> + * When the driver is there, it will call SPI setup again with the
> + * correct number of bits per transfer.
> + * If a driver setups with the wrong bit number, it will fail when
> + * it tries to do a transfer
> + */
> return 0;
> }
>
> static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi)
> {
> u8 sr;
> + u8 wsize;
> + if (xspi->bits_per_word == 8)
> + wsize = 1;
> + else if (xspi->bits_per_word == 16)
> + wsize = 2;
> + else
> + wsize = 4;
wsize = xspi->bits_per_word / 8 perhaps?
>
> /* Fill the Tx FIFO with as many bytes as possible */
> sr = xspi_read8(xspi, XSPI_SR_OFFSET);
> - while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) {
> + while ((sr & XSPI_SR_TX_FULL_MASK) == 0 &&
> + xspi->remaining_bytes > 0) {
> if (xspi->tx_ptr) {
> - xspi_write8(xspi, XSPI_TXD_OFFSET, *xspi->tx_ptr++);
> - } else {
> + if (wsize == 1)
> + xspi_write8(xspi, XSPI_TXD_OFFSET,
> + *xspi->tx_ptr);
> + else if (wsize == 2)
> + xspi_write16(xspi, XSPI_TXD_OFFSET,
> + *(u16 *)(xspi->tx_ptr));
> + else if (wsize == 4)
> + xspi_write32(xspi, XSPI_TXD_OFFSET,
> + *(u32 *)(xspi->tx_ptr));
> +
> + xspi->tx_ptr += wsize;
This would go better as a callback instead of performing the same test
*every time* through the loop. Make for simpler code too.
> + } else
> xspi_write8(xspi, XSPI_TXD_OFFSET, 0);
> - }
> - xspi->remaining_bytes--;
> + xspi->remaining_bytes -= wsize;
> sr = xspi_read8(xspi, XSPI_SR_OFFSET);
> }
> }
> @@ -283,6 +306,13 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
> if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */
> u16 cr;
> u8 sr;
> + u8 rsize;
> + if (xspi->bits_per_word == 8)
> + rsize = 1;
> + else if (xspi->bits_per_word == 16)
> + rsize = 2;
> + else
> + rsize = 4;
Ditto.
>
> /* A transmit has just completed. Process received data and
> * check for more data to transmit. Always inhibit the
> @@ -295,11 +325,22 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
> /* Read out all the data from the Rx FIFO */
> sr = xspi_read8(xspi, XSPI_SR_OFFSET);
> while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) {
> - u8 data;
> + u32 data;
> + if (rsize == 1)
> + data = xspi_read8(xspi, XSPI_RXD_OFFSET);
> + else if (rsize == 2)
> + data = xspi_read16(xspi, XSPI_RXD_OFFSET);
> + else
> + data = xspi_read32(xspi, XSPI_RXD_OFFSET);
>
> - data = xspi_read8(xspi, XSPI_RXD_OFFSET);
> if (xspi->rx_ptr) {
> - *xspi->rx_ptr++ = data;
> + if (rsize == 1)
> + *xspi->rx_ptr = data & 0xff;
> + else if (rsize == 2)
> + *(u16 *)(xspi->rx_ptr) = data & 0xffff;
> + else
> + *((u32 *)(xspi->rx_ptr)) = data;
> + xspi->rx_ptr += rsize;
ditto
> }
> sr = xspi_read8(xspi, XSPI_SR_OFFSET);
> }
> @@ -323,7 +364,8 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
> }
>
> struct spi_master *xilinx_spi_init(struct device *dev, struct resource *mem,
> - u32 irq, s16 bus_num, u16 num_chipselect, bool big_endian)
> + u32 irq, s16 bus_num, u16 num_chipselect, bool big_endian,
> + u8 bits_per_word)
As mentioned in my comments in patch 1/4; the increase to the
parameters to _init() would not be needed if the of_driver stowed
everything into a pdata structure.
Cheers,
g.
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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