[U-Boot] [PATCH] Adds driver for Xilinx' xps_spi SPI controller

[Graeme Smecher <graeme.smecher@mail.mcgill.ca>]

  Hi all,

I neglected to point out that this driver has been tested with Thomas 
Chou's mmc_spi patches, and appears to work with SPI flash (Winbond 
w25q64) as well.

A quick diff shows this driver is nearly identical to the altera_spi 
driver. The only differences are:

     * the CS register is active-low here, and
     * the control register requires some additional setup.

cheers,
Graeme Smecher

On 10-07-27 09:56 AM, Graeme Smecher wrote:
> ---
>   drivers/spi/Makefile     |    1 +
>   drivers/spi/xilinx_spi.c |  171 ++++++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 172 insertions(+), 0 deletions(-)
>   create mode 100644 drivers/spi/xilinx_spi.c
>
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index dfcbb8b..34e0f31 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -26,6 +26,7 @@ include $(TOPDIR)/config.mk
>   LIB	:= $(obj)libspi.a
>
>   COBJS-$(CONFIG_ALTERA_SPI) += altera_spi.o
> +COBJS-$(CONFIG_XILINX_SPI) += xilinx_spi.o
>   COBJS-$(CONFIG_ATMEL_DATAFLASH_SPI) += atmel_dataflash_spi.o
>   COBJS-$(CONFIG_ATMEL_SPI) += atmel_spi.o
>   COBJS-$(CONFIG_BFIN_SPI) += bfin_spi.o
> diff --git a/drivers/spi/xilinx_spi.c b/drivers/spi/xilinx_spi.c
> new file mode 100644
> index 0000000..99ce661
> --- /dev/null
> +++ b/drivers/spi/xilinx_spi.c
> @@ -0,0 +1,171 @@
> +/*
> + * Xilinx SPI driver
> + *
> + * based on bfin_spi.c, by way of altera_spi.c
> + * Copyright (c) 2005-2008 Analog Devices Inc.
> + * Copyright (c) 2010 Thomas Chou<thomas@wytron.com.tw>
> + * Copyright (c) 2010 Graeme Smecher<graeme.smecher@mail.mcgill.ca>
> + *
> + * Licensed under the GPL-2 or later.
> + */
> +#include<common.h>
> +#include<asm/io.h>
> +#include<malloc.h>
> +#include<spi.h>
> +
> +#define debug printf
> +
> +#define XILINX_SPI_RR			0x6c
> +#define XILINX_SPI_TR			0x68
> +#define XILINX_SPI_SR			0x64
> +#define XILINX_SPI_CR			0x60
> +#define XILINX_SPI_SSR			0x70
> +
> +#define XILINX_SPI_SR_RX_EMPTY_MSK	0x01
> +
> +#define XILINX_SPI_CR_DEFAULT		(0x0086)
> +
> +#if XPAR_XSPI_NUM_INSTANCES>  4
> +# warning "The xilinx_spi driver will ignore some of your SPI peripherals!"
> +#endif
> +
> +static ulong xilinx_spi_base_list[] = {
> +#ifdef XPAR_SPI_0_BASEADDR
> +	XPAR_SPI_0_BASEADDR,
> +#endif
> +#ifdef XPAR_SPI_1_BASEADDR
> +	XPAR_SPI_1_BASEADDR,
> +#endif
> +#ifdef XPAR_SPI_2_BASEADDR
> +	XPAR_SPI_2_BASEADDR,
> +#endif
> +#ifdef XPAR_SPI_3_BASEADDR
> +	XPAR_SPI_3_BASEADDR,
> +#endif
> +};
> +
> +struct xilinx_spi_slave {
> +	struct spi_slave slave;
> +	ulong base;
> +};
> +#define to_xilinx_spi_slave(s) container_of(s, struct xilinx_spi_slave, slave)
> +
> +__attribute__((weak))
> +int spi_cs_is_valid(unsigned int bus, unsigned int cs)
> +{
> +	return bus<  ARRAY_SIZE(xilinx_spi_base_list)&&  cs<  32;
> +}
> +
> +__attribute__((weak))
> +void spi_cs_activate(struct spi_slave *slave)
> +{
> +	struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave);
> +	writel(~(1<<  slave->cs), xilspi->base + XILINX_SPI_SSR);
> +}
> +
> +__attribute__((weak))
> +void spi_cs_deactivate(struct spi_slave *slave)
> +{
> +	struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave);
> +	writel(~0, xilspi->base + XILINX_SPI_SSR);
> +}
> +
> +void spi_init(void)
> +{
> +}
> +
> +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
> +				  unsigned int max_hz, unsigned int mode)
> +{
> +	struct xilinx_spi_slave *xilspi;
> +
> +	if (!spi_cs_is_valid(bus, cs))
> +		return NULL;
> +
> +	xilspi = malloc(sizeof(*xilspi));
> +	if (!xilspi)
> +		return NULL;
> +
> +	xilspi->slave.bus = bus;
> +	xilspi->slave.cs = cs;
> +	xilspi->base = xilinx_spi_base_list[bus];
> +	debug("%s: bus:%i cs:%i base:%lx\n", __func__,
> +		bus, cs, xilspi->base);
> +
> +	writel(XILINX_SPI_CR_DEFAULT, xilspi->base + XILINX_SPI_CR);
> +
> +	return&xilspi->slave;
> +}
> +
> +void spi_free_slave(struct spi_slave *slave)
> +{
> +	struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave);
> +	free(xilspi);
> +}
> +
> +int spi_claim_bus(struct spi_slave *slave)
> +{
> +	struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave);
> +
> +	debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
> +	writel(~0, xilspi->base + XILINX_SPI_SSR);
> +	return 0;
> +}
> +
> +void spi_release_bus(struct spi_slave *slave)
> +{
> +	struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave);
> +
> +	debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
> +	writel(~0, xilspi->base + XILINX_SPI_SSR);
> +}
> +
> +#ifndef CONFIG_XILINX_SPI_IDLE_VAL
> +# define CONFIG_XILINX_SPI_IDLE_VAL 0xff
> +#endif
> +
> +int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
> +	     void *din, unsigned long flags)
> +{
> +	struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave);
> +	/* assume spi core configured to do 8 bit transfers */
> +	uint bytes = bitlen / 8;
> +	const uchar *txp = dout;
> +	uchar *rxp = din;
> +
> +	debug("%s: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n", __func__,
> +		slave->bus, slave->cs, bitlen, bytes, flags);
> +	if (bitlen == 0)
> +		goto done;
> +
> +	if (bitlen % 8) {
> +		flags |= SPI_XFER_END;
> +		goto done;
> +	}
> +
> +	/* empty read buffer */
> +	while (!(readl(xilspi->base + XILINX_SPI_SR)&
> +	    XILINX_SPI_SR_RX_EMPTY_MSK))
> +		readl(xilspi->base + XILINX_SPI_RR);
> +
> +	if (flags&  SPI_XFER_BEGIN)
> +		spi_cs_activate(slave);
> +
> +	while (bytes--) {
> +		uchar d = txp ? *txp++ : CONFIG_XILINX_SPI_IDLE_VAL;
> +		debug("%s: tx:%x ", __func__, d);
> +		writel(d, xilspi->base + XILINX_SPI_TR);
> +		while (readl(xilspi->base + XILINX_SPI_SR)&
> +			 XILINX_SPI_SR_RX_EMPTY_MSK)
> +			;
> +		d = readl(xilspi->base + XILINX_SPI_RR);
> +		if (rxp)
> +			*rxp++ = d;
> +		debug("rx:%x\n", d);
> +	}
> + done:
> +	if (flags&  SPI_XFER_END)
> +		spi_cs_deactivate(slave);
> +
> +	return 0;
> +}