LXR uboot/drivers/spi/mpc8xxx

   1/*
   2 * Copyright (c) 2006 Ben Warren, Qstreams Networks Inc.
   3 * With help from the common/soft_spi and arch/powerpc/cpu/mpc8260 drivers
   4 *
   5 * See file CREDITS for list of people who contributed to this
   6 * project.
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License as
  10 * published by the Free Software Foundation; either version 2 of
  11 * the License, or (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21 * MA 02111-1307 USA
  22 */
  23
  24#include <common.h>
  25
  26#include <malloc.h>
  27#include <spi.h>
  28#include <asm/mpc8xxx_spi.h>
  29
  30#define SPI_EV_NE       (0x80000000 >> 22)      /* Receiver Not Empty */
  31#define SPI_EV_NF       (0x80000000 >> 23)      /* Transmitter Not Full */
  32
  33#define SPI_MODE_LOOP   (0x80000000 >> 1)       /* Loopback mode */
  34#define SPI_MODE_REV    (0x80000000 >> 5)       /* Reverse mode - MSB first */
  35#define SPI_MODE_MS     (0x80000000 >> 6)       /* Always master */
  36#define SPI_MODE_EN     (0x80000000 >> 7)       /* Enable interface */
  37
  38#define SPI_TIMEOUT     1000
  39
  40struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  41                unsigned int max_hz, unsigned int mode)
  42{
  43        struct spi_slave *slave;
  44
  45        if (!spi_cs_is_valid(bus, cs))
  46                return NULL;
  47
  48        slave = malloc(sizeof(struct spi_slave));
  49        if (!slave)
  50                return NULL;
  51
  52        slave->bus = bus;
  53        slave->cs = cs;
  54
  55        /*
  56         * TODO: Some of the code in spi_init() should probably move
  57         * here, or into spi_claim_bus() below.
  58         */
  59
  60        return slave;
  61}
  62
  63void spi_free_slave(struct spi_slave *slave)
  64{
  65        free(slave);
  66}
  67
  68void spi_init(void)
  69{
  70        volatile spi8xxx_t *spi = &((immap_t *) (CONFIG_SYS_IMMR))->spi;
  71
  72        /*
  73         * SPI pins on the MPC83xx are not muxed, so all we do is initialize
  74         * some registers
  75         */
  76        spi->mode = SPI_MODE_REV | SPI_MODE_MS | SPI_MODE_EN;
  77        spi->mode = (spi->mode & 0xfff0ffff) | (1 << 16); /* Use SYSCLK / 8
  78                                                             (16.67MHz typ.) */
  79        spi->event = 0xffffffff;        /* Clear all SPI events */
  80        spi->mask = 0x00000000; /* Mask  all SPI interrupts */
  81        spi->com = 0;           /* LST bit doesn't do anything, so disregard */
  82}
  83
  84int spi_claim_bus(struct spi_slave *slave)
  85{
  86        return 0;
  87}
  88
  89void spi_release_bus(struct spi_slave *slave)
  90{
  91
  92}
  93
  94int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
  95                void *din, unsigned long flags)
  96{
  97        volatile spi8xxx_t *spi = &((immap_t *) (CONFIG_SYS_IMMR))->spi;
  98        unsigned int tmpdout, tmpdin, event;
  99        int numBlks = bitlen / 32 + (bitlen % 32 ? 1 : 0);
 100        int tm, isRead = 0;
 101        unsigned char charSize = 32;
 102
 103        debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
 104              slave->bus, slave->cs, *(uint *) dout, *(uint *) din, bitlen);
 105
 106        if (flags & SPI_XFER_BEGIN)
 107                spi_cs_activate(slave);
 108
 109        spi->event = 0xffffffff;        /* Clear all SPI events */
 110
 111        /* handle data in 32-bit chunks */
 112        while (numBlks--) {
 113                tmpdout = 0;
 114                charSize = (bitlen >= 32 ? 32 : bitlen);
 115
 116                /* Shift data so it's msb-justified */
 117                tmpdout = *(u32 *) dout >> (32 - charSize);
 118
 119                /* The LEN field of the SPMODE register is set as follows:
 120                 *
 121                 * Bit length             setting
 122                 * len <= 4               3
 123                 * 4 < len <= 16          len - 1
 124                 * len > 16               0
 125                 */
 126
 127                if (bitlen <= 16) {
 128                        if (bitlen <= 4)
 129                                spi->mode = (spi->mode & 0xff0fffff) |
 130                                            (3 << 20);
 131                        else
 132                                spi->mode = (spi->mode & 0xff0fffff) |
 133                                            ((bitlen - 1) << 20);
 134                } else {
 135                        spi->mode = (spi->mode & 0xff0fffff);
 136                        /* Set up the next iteration if sending > 32 bits */
 137                        bitlen -= 32;
 138                        dout += 4;
 139                }
 140
 141                spi->tx = tmpdout;      /* Write the data out */
 142                debug("*** spi_xfer: ... %08x written\n", tmpdout);
 143
 144                /*
 145                 * Wait for SPI transmit to get out
 146                 * or time out (1 second = 1000 ms)
 147                 * The NE event must be read and cleared first
 148                 */
 149                for (tm = 0, isRead = 0; tm < SPI_TIMEOUT; ++tm) {
 150                        event = spi->event;
 151                        if (event & SPI_EV_NE) {
 152                                tmpdin = spi->rx;
 153                                spi->event |= SPI_EV_NE;
 154                                isRead = 1;
 155
 156                                *(u32 *) din = (tmpdin << (32 - charSize));
 157                                if (charSize == 32) {
 158                                        /* Advance output buffer by 32 bits */
 159                                        din += 4;
 160                                }
 161                        }
 162                        /*
 163                         * Only bail when we've had both NE and NF events.
 164                         * This will cause timeouts on RO devices, so maybe
 165                         * in the future put an arbitrary delay after writing
 166                         * the device.  Arbitrary delays suck, though...
 167                         */
 168                        if (isRead && (event & SPI_EV_NF))
 169                                break;
 170                }
 171                if (tm >= SPI_TIMEOUT)
 172                        puts("*** spi_xfer: Time out during SPI transfer");
 173
 174                debug("*** spi_xfer: transfer ended. Value=%08x\n", tmpdin);
 175        }
 176
 177        if (flags & SPI_XFER_END)
 178                spi_cs_deactivate(slave);
 179
 180        return 0;
 181}
 182