drivers/spi/sandbox_spi.c

   1 /*
   2  * Simulate a SPI port
   3  *
   4  * Copyright (c) 2011-2013 The Chromium OS Authors.
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * Licensed under the GPL-2 or later.
   9  */
  10
  11 #include <common.h>
  12 #include <dm.h>
  13 #include <malloc.h>
  14 #include <spi.h>
  15 #include <spi_flash.h>
  16 #include <os.h>
  17
  18 #include <linux/errno.h>
  19 #include <asm/spi.h>
  20 #include <asm/state.h>
  21 #include <dm/device-internal.h>
  22
  23 DECLARE_GLOBAL_DATA_PTR;
  24
  25 #ifndef CONFIG_SPI_IDLE_VAL
  26 # define CONFIG_SPI_IDLE_VAL 0xFF
  27 #endif
  28
  29 const char *sandbox_spi_parse_spec(const char *arg, unsigned long *bus,
  30                                    unsigned long *cs)
  31 {
  32         char *endp;
  33
  34         *bus = simple_strtoul(arg, &endp, 0);
  35         if (*endp != ':' || *bus >= CONFIG_SANDBOX_SPI_MAX_BUS)
  36                 return NULL;
  37
  38         *cs = simple_strtoul(endp + 1, &endp, 0);
  39         if (*endp != ':' || *cs >= CONFIG_SANDBOX_SPI_MAX_CS)
  40                 return NULL;
  41
  42         return endp + 1;
  43 }
  44
  45 __weak int sandbox_spi_get_emul(struct sandbox_state *state,
  46                                 struct udevice *bus, struct udevice *slave,
  47                                 struct udevice **emulp)
  48 {
  49         return -ENOENT;
  50 }
  51
  52 static int sandbox_spi_xfer(struct udevice *slave, unsigned int bitlen,
  53                             const void *dout, void *din, unsigned long flags)
  54 {
  55         struct udevice *bus = slave->parent;
  56         struct sandbox_state *state = state_get_current();
  57         struct dm_spi_emul_ops *ops;
  58         struct udevice *emul;
  59         uint bytes = bitlen / 8, i;
  60         int ret;
  61         u8 *tx = (void *)dout, *rx = din;
  62         uint busnum, cs;
  63
  64         if (bitlen == 0)
  65                 return 0;
  66
  67         /* we can only do 8 bit transfers */
  68         if (bitlen % 8) {
  69                 printf("sandbox_spi: xfer: invalid bitlen size %u; needs to be 8bit\n",
  70                        bitlen);
  71                 return -EINVAL;
  72         }
  73
  74         busnum = bus->seq;
  75         cs = spi_chip_select(slave);
  76         if (busnum >= CONFIG_SANDBOX_SPI_MAX_BUS ||
  77             cs >= CONFIG_SANDBOX_SPI_MAX_CS) {
  78                 printf("%s: busnum=%u, cs=%u: out of range\n", __func__,
  79                        busnum, cs);
  80                 return -ENOENT;
  81         }
  82         ret = sandbox_spi_get_emul(state, bus, slave, &emul);
  83         if (ret) {
  84                 printf("%s: busnum=%u, cs=%u: no emulation available (err=%d)\n",
  85                        __func__, busnum, cs, ret);
  86                 return -ENOENT;
  87         }
  88         ret = device_probe(emul);
  89         if (ret)
  90                 return ret;
  91
  92         /* make sure rx/tx buffers are full so clients can assume */
  93         if (!tx) {
  94                 debug("sandbox_spi: xfer: auto-allocating tx scratch buffer\n");
  95                 tx = malloc(bytes);
  96                 if (!tx) {
  97                         debug("sandbox_spi: Out of memory\n");
  98                         return -ENOMEM;
  99                 }
 100         }
 101         if (!rx) {
 102                 debug("sandbox_spi: xfer: auto-allocating rx scratch buffer\n");
 103                 rx = malloc(bytes);
 104                 if (!rx) {
 105                         debug("sandbox_spi: Out of memory\n");
 106                         return -ENOMEM;
 107                 }
 108         }
 109
 110         ops = spi_emul_get_ops(emul);
 111         ret = ops->xfer(emul, bitlen, dout, din, flags);
 112
 113         debug("sandbox_spi: xfer: got back %i (that's %s)\n rx:",
 114               ret, ret ? "bad" : "good");
 115         for (i = 0; i < bytes; ++i)
 116                 debug(" %u:%02x", i, rx[i]);
 117         debug("\n");
 118
 119         if (tx != dout)
 120                 free(tx);
 121         if (rx != din)
 122                 free(rx);
 123
 124         return ret;
 125 }
 126
 127 static int sandbox_spi_set_speed(struct udevice *bus, uint speed)
 128 {
 129         return 0;
 130 }
 131
 132 static int sandbox_spi_set_mode(struct udevice *bus, uint mode)
 133 {
 134         return 0;
 135 }
 136
 137 static int sandbox_cs_info(struct udevice *bus, uint cs,
 138                            struct spi_cs_info *info)
 139 {
 140         /* Always allow activity on CS 0 */
 141         if (cs >= 1)
 142                 return -ENODEV;
 143
 144         return 0;
 145 }
 146
 147 static const struct dm_spi_ops sandbox_spi_ops = {
 148         .xfer           = sandbox_spi_xfer,
 149         .set_speed      = sandbox_spi_set_speed,
 150         .set_mode       = sandbox_spi_set_mode,
 151         .cs_info        = sandbox_cs_info,
 152 };
 153
 154 static const struct udevice_id sandbox_spi_ids[] = {
 155         { .compatible = "sandbox,spi" },
 156         { }
 157 };
 158
 159 U_BOOT_DRIVER(spi_sandbox) = {
 160         .name   = "spi_sandbox",
 161         .id     = UCLASS_SPI,
 162         .of_match = sandbox_spi_ids,
 163         .ops    = &sandbox_spi_ops,
 164 };