drivers/spi/altera_spi.c

   1 /*
   2  * Altera SPI driver
   3  *
   4  * based on bfin_spi.c
   5  * Copyright (c) 2005-2008 Analog Devices Inc.
   6  * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
   7  *
   8  * Licensed under the GPL-2 or later.
   9  */
  10 #include <common.h>
  11 #include <asm/io.h>
  12 #include <malloc.h>
  13 #include <spi.h>
  14
  15 #define ALTERA_SPI_RXDATA       0
  16 #define ALTERA_SPI_TXDATA       4
  17 #define ALTERA_SPI_STATUS       8
  18 #define ALTERA_SPI_CONTROL      12
  19 #define ALTERA_SPI_SLAVE_SEL    20
  20
  21 #define ALTERA_SPI_STATUS_ROE_MSK       (0x8)
  22 #define ALTERA_SPI_STATUS_TOE_MSK       (0x10)
  23 #define ALTERA_SPI_STATUS_TMT_MSK       (0x20)
  24 #define ALTERA_SPI_STATUS_TRDY_MSK      (0x40)
  25 #define ALTERA_SPI_STATUS_RRDY_MSK      (0x80)
  26 #define ALTERA_SPI_STATUS_E_MSK (0x100)
  27
  28 #define ALTERA_SPI_CONTROL_IROE_MSK     (0x8)
  29 #define ALTERA_SPI_CONTROL_ITOE_MSK     (0x10)
  30 #define ALTERA_SPI_CONTROL_ITRDY_MSK    (0x40)
  31 #define ALTERA_SPI_CONTROL_IRRDY_MSK    (0x80)
  32 #define ALTERA_SPI_CONTROL_IE_MSK       (0x100)
  33 #define ALTERA_SPI_CONTROL_SSO_MSK      (0x400)
  34
  35 #ifndef CONFIG_SYS_ALTERA_SPI_LIST
  36 #define CONFIG_SYS_ALTERA_SPI_LIST { CONFIG_SYS_SPI_BASE }
  37 #endif
  38
  39 static ulong altera_spi_base_list[] = CONFIG_SYS_ALTERA_SPI_LIST;
  40
  41 struct altera_spi_slave {
  42         struct spi_slave slave;
  43         ulong base;
  44 };
  45 #define to_altera_spi_slave(s) container_of(s, struct altera_spi_slave, slave)
  46
  47 __attribute__((weak))
  48 int spi_cs_is_valid(unsigned int bus, unsigned int cs)
  49 {
  50         return bus < ARRAY_SIZE(altera_spi_base_list) && cs < 32;
  51 }
  52
  53 __attribute__((weak))
  54 void spi_cs_activate(struct spi_slave *slave)
  55 {
  56         struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
  57         writel(1 << slave->cs, altspi->base + ALTERA_SPI_SLAVE_SEL);
  58         writel(ALTERA_SPI_CONTROL_SSO_MSK, altspi->base + ALTERA_SPI_CONTROL);
  59 }
  60
  61 __attribute__((weak))
  62 void spi_cs_deactivate(struct spi_slave *slave)
  63 {
  64         struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
  65         writel(0, altspi->base + ALTERA_SPI_CONTROL);
  66         writel(0, altspi->base + ALTERA_SPI_SLAVE_SEL);
  67 }
  68
  69 void spi_init(void)
  70 {
  71 }
  72
  73 void spi_set_speed(struct spi_slave *slave, uint hz)
  74 {
  75         /* altera spi core does not support programmable speed */
  76 }
  77
  78 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  79                                   unsigned int max_hz, unsigned int mode)
  80 {
  81         struct altera_spi_slave *altspi;
  82
  83         if (!spi_cs_is_valid(bus, cs))
  84                 return NULL;
  85
  86         altspi = spi_alloc_slave(struct altera_spi_slave, bus, cs);
  87         if (!altspi)
  88                 return NULL;
  89
  90         altspi->base = altera_spi_base_list[bus];
  91         debug("%s: bus:%i cs:%i base:%lx\n", __func__,
  92                 bus, cs, altspi->base);
  93
  94         return &altspi->slave;
  95 }
  96
  97 void spi_free_slave(struct spi_slave *slave)
  98 {
  99         struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
 100         free(altspi);
 101 }
 102
 103 int spi_claim_bus(struct spi_slave *slave)
 104 {
 105         struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
 106
 107         debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
 108         writel(0, altspi->base + ALTERA_SPI_CONTROL);
 109         writel(0, altspi->base + ALTERA_SPI_SLAVE_SEL);
 110         return 0;
 111 }
 112
 113 void spi_release_bus(struct spi_slave *slave)
 114 {
 115         struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
 116
 117         debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
 118         writel(0, altspi->base + ALTERA_SPI_SLAVE_SEL);
 119 }
 120
 121 #ifndef CONFIG_ALTERA_SPI_IDLE_VAL
 122 # define CONFIG_ALTERA_SPI_IDLE_VAL 0xff
 123 #endif
 124
 125 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
 126              void *din, unsigned long flags)
 127 {
 128         struct altera_spi_slave *altspi = to_altera_spi_slave(slave);
 129         /* assume spi core configured to do 8 bit transfers */
 130         uint bytes = bitlen / 8;
 131         const uchar *txp = dout;
 132         uchar *rxp = din;
 133
 134         debug("%s: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n", __func__,
 135                 slave->bus, slave->cs, bitlen, bytes, flags);
 136         if (bitlen == 0)
 137                 goto done;
 138
 139         if (bitlen % 8) {
 140                 flags |= SPI_XFER_END;
 141                 goto done;
 142         }
 143
 144         /* empty read buffer */
 145         if (readl(altspi->base + ALTERA_SPI_STATUS) &
 146             ALTERA_SPI_STATUS_RRDY_MSK)
 147                 readl(altspi->base + ALTERA_SPI_RXDATA);
 148         if (flags & SPI_XFER_BEGIN)
 149                 spi_cs_activate(slave);
 150
 151         while (bytes--) {
 152                 uchar d = txp ? *txp++ : CONFIG_ALTERA_SPI_IDLE_VAL;
 153                 debug("%s: tx:%x ", __func__, d);
 154                 writel(d, altspi->base + ALTERA_SPI_TXDATA);
 155                 while (!(readl(altspi->base + ALTERA_SPI_STATUS) &
 156                          ALTERA_SPI_STATUS_RRDY_MSK))
 157                         ;
 158                 d = readl(altspi->base + ALTERA_SPI_RXDATA);
 159                 if (rxp)
 160                         *rxp++ = d;
 161                 debug("rx:%x\n", d);
 162         }
 163  done:
 164         if (flags & SPI_XFER_END)
 165                 spi_cs_deactivate(slave);
 166
 167         return 0;
 168 }