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  • /*
     * Altera SPI driver
     *
     * based on bfin_spi.c
     * Copyright (c) 2005-2008 Analog Devices Inc.
     * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
     *
     * Licensed under the GPL-2 or later.
     */
    #include <common.h>
    #include <asm/io.h>
    #include <malloc.h>
    #include <spi.h>
    
    #define ALTERA_SPI_RXDATA	0
    #define ALTERA_SPI_TXDATA	4
    #define ALTERA_SPI_STATUS	8
    #define ALTERA_SPI_CONTROL	12
    #define ALTERA_SPI_SLAVE_SEL	20
    
    #define ALTERA_SPI_STATUS_ROE_MSK	(0x8)
    #define ALTERA_SPI_STATUS_TOE_MSK	(0x10)
    #define ALTERA_SPI_STATUS_TMT_MSK	(0x20)
    #define ALTERA_SPI_STATUS_TRDY_MSK	(0x40)
    #define ALTERA_SPI_STATUS_RRDY_MSK	(0x80)
    #define ALTERA_SPI_STATUS_E_MSK	(0x100)
    
    #define ALTERA_SPI_CONTROL_IROE_MSK	(0x8)
    #define ALTERA_SPI_CONTROL_ITOE_MSK	(0x10)
    #define ALTERA_SPI_CONTROL_ITRDY_MSK	(0x40)
    #define ALTERA_SPI_CONTROL_IRRDY_MSK	(0x80)
    #define ALTERA_SPI_CONTROL_IE_MSK	(0x100)
    #define ALTERA_SPI_CONTROL_SSO_MSK	(0x400)
    
    #ifndef CONFIG_SYS_ALTERA_SPI_LIST
    #define CONFIG_SYS_ALTERA_SPI_LIST { CONFIG_SYS_SPI_BASE }
    #endif
    
    static ulong altera_spi_base_list[] = CONFIG_SYS_ALTERA_SPI_LIST;
    
    struct altera_spi_slave {
    	struct spi_slave slave;
    	ulong base;
    };
    #define to_altera_spi_slave(s) container_of(s, struct altera_spi_slave, slave)
    
    __attribute__((weak))
    int spi_cs_is_valid(unsigned int bus, unsigned int cs)
    {
    	return bus < ARRAY_SIZE(altera_spi_base_list) && cs < 32;
    }
    
    __attribute__((weak))
    void spi_cs_activate(struct spi_slave *slave)
    {
    	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
    	writel(1 << slave->cs, altspi->base + ALTERA_SPI_SLAVE_SEL);
    	writel(ALTERA_SPI_CONTROL_SSO_MSK, altspi->base + ALTERA_SPI_CONTROL);
    }
    
    __attribute__((weak))
    void spi_cs_deactivate(struct spi_slave *slave)
    {
    	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
    	writel(0, altspi->base + ALTERA_SPI_CONTROL);
    	writel(0, altspi->base + ALTERA_SPI_SLAVE_SEL);
    }
    
    void spi_init(void)
    {
    }
    
    struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
    				  unsigned int max_hz, unsigned int mode)
    {
    	struct altera_spi_slave *altspi;
    
    	if (!spi_cs_is_valid(bus, cs))
    		return NULL;
    
    	altspi = malloc(sizeof(*altspi));
    	if (!altspi)
    		return NULL;
    
    	altspi->slave.bus = bus;
    	altspi->slave.cs = cs;
    	altspi->base = altera_spi_base_list[bus];
    	debug("%s: bus:%i cs:%i base:%lx\n", __func__,
    		bus, cs, altspi->base);
    
    	return &altspi->slave;
    }
    
    void spi_free_slave(struct spi_slave *slave)
    {
    	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
    	free(altspi);
    }
    
    int spi_claim_bus(struct spi_slave *slave)
    {
    	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
    
    	debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
    	writel(0, altspi->base + ALTERA_SPI_CONTROL);
    	writel(0, altspi->base + ALTERA_SPI_SLAVE_SEL);
    	return 0;
    }
    
    void spi_release_bus(struct spi_slave *slave)
    {
    	struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
    
    	debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
    	writel(0, altspi->base + ALTERA_SPI_SLAVE_SEL);
    }
    
    #ifndef CONFIG_ALTERA_SPI_IDLE_VAL
    # define CONFIG_ALTERA_SPI_IDLE_VAL 0xff
    #endif
    
    int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
    	     void *din, unsigned long flags)
    {
    	struct altera_spi_slave *altspi = to_altera_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 */
    	if (readl(altspi->base + ALTERA_SPI_STATUS) &
    	    ALTERA_SPI_STATUS_RRDY_MSK)
    		readl(altspi->base + ALTERA_SPI_RXDATA);
    	if (flags & SPI_XFER_BEGIN)
    		spi_cs_activate(slave);
    
    	while (bytes--) {
    		uchar d = txp ? *txp++ : CONFIG_ALTERA_SPI_IDLE_VAL;
    		debug("%s: tx:%x ", __func__, d);
    		writel(d, altspi->base + ALTERA_SPI_TXDATA);
    		while (!(readl(altspi->base + ALTERA_SPI_STATUS) &
    			 ALTERA_SPI_STATUS_RRDY_MSK))
    			;
    		d = readl(altspi->base + ALTERA_SPI_RXDATA);
    		if (rxp)
    			*rxp++ = d;
    		debug("rx:%x\n", d);
    	}
     done:
    	if (flags & SPI_XFER_END)
    		spi_cs_deactivate(slave);
    
    	return 0;
    }