src/drivers/spi/spi-generic.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <assert.h>
  16 #include <commonlib/helpers.h>
  17 #include <spi-generic.h>
  18 #include <stddef.h>
  19 #include <string.h>
  20
  21 int spi_claim_bus(const struct spi_slave *slave)
  22 {
  23         const struct spi_ctrlr *ctrlr = slave->ctrlr;
  24         if (ctrlr && ctrlr->claim_bus)
  25                 return ctrlr->claim_bus(slave);
  26         return 0;
  27 }
  28
  29 void spi_release_bus(const struct spi_slave *slave)
  30 {
  31         const struct spi_ctrlr *ctrlr = slave->ctrlr;
  32         if (ctrlr && ctrlr->release_bus)
  33                 ctrlr->release_bus(slave);
  34 }
  35
  36 static int spi_xfer_single_op(const struct spi_slave *slave,
  37                         struct spi_op *op)
  38 {
  39         const struct spi_ctrlr *ctrlr = slave->ctrlr;
  40         int ret;
  41
  42         if (!ctrlr || !ctrlr->xfer)
  43                 return -1;
  44
  45         ret = ctrlr->xfer(slave, op->dout, op->bytesout, op->din, op->bytesin);
  46         if (ret)
  47                 op->status = SPI_OP_FAILURE;
  48         else
  49                 op->status = SPI_OP_SUCCESS;
  50
  51         return ret;
  52 }
  53
  54 static int spi_xfer_vector_default(const struct spi_slave *slave,
  55                                 struct spi_op vectors[], size_t count)
  56 {
  57         size_t i;
  58         int ret;
  59
  60         for (i = 0; i < count; i++) {
  61                 ret = spi_xfer_single_op(slave, &vectors[i]);
  62                 if (ret)
  63                         return ret;
  64         }
  65
  66         return 0;
  67 }
  68
  69 int spi_xfer_vector(const struct spi_slave *slave,
  70                 struct spi_op vectors[], size_t count)
  71 {
  72         const struct spi_ctrlr *ctrlr = slave->ctrlr;
  73
  74         if (ctrlr && ctrlr->xfer_vector)
  75                 return ctrlr->xfer_vector(slave, vectors, count);
  76
  77         return spi_xfer_vector_default(slave, vectors, count);
  78 }
  79
  80 int spi_xfer(const struct spi_slave *slave, const void *dout, size_t bytesout,
  81              void *din, size_t bytesin)
  82 {
  83         const struct spi_ctrlr *ctrlr = slave->ctrlr;
  84
  85         if (ctrlr && ctrlr->xfer)
  86                 return ctrlr->xfer(slave, dout, bytesout, din, bytesin);
  87
  88         return -1;
  89 }
  90
  91 unsigned int spi_crop_chunk(const struct spi_slave *slave, unsigned int cmd_len,
  92                         unsigned int buf_len)
  93 {
  94         const struct spi_ctrlr *ctrlr = slave->ctrlr;
  95         unsigned int ctrlr_max;
  96         bool deduct_cmd_len;
  97         bool deduct_opcode_len;
  98
  99         if (!ctrlr)
 100                 return 0;
 101
 102         deduct_cmd_len = !!(ctrlr->flags & SPI_CNTRLR_DEDUCT_CMD_LEN);
 103         deduct_opcode_len = !!(ctrlr->flags & SPI_CNTRLR_DEDUCT_OPCODE_LEN);
 104         ctrlr_max = ctrlr->max_xfer_size;
 105
 106         assert (ctrlr_max != 0);
 107
 108         /* Assume opcode is always one byte and deduct it from the cmd_len
 109            as the hardware has a separate register for the opcode. */
 110         if (deduct_opcode_len)
 111                 cmd_len--;
 112
 113         if (deduct_cmd_len && (ctrlr_max > cmd_len))
 114                 ctrlr_max -= cmd_len;
 115
 116         return MIN(ctrlr_max, buf_len);
 117 }
 118
 119 void __weak spi_init(void)
 120 {
 121         /* Default weak implementation - do nothing. */
 122 }
 123
 124 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)
 125 {
 126         size_t i;
 127
 128         memset(slave, 0, sizeof(*slave));
 129
 130         for (i = 0; i < spi_ctrlr_bus_map_count; i++) {
 131                 if ((spi_ctrlr_bus_map[i].bus_start <= bus) &&
 132                     (spi_ctrlr_bus_map[i].bus_end >= bus)) {
 133                         slave->ctrlr = spi_ctrlr_bus_map[i].ctrlr;
 134                         break;
 135                 }
 136         }
 137
 138         if (slave->ctrlr == NULL)
 139                 return -1;
 140
 141         slave->bus = bus;
 142         slave->cs = cs;
 143
 144         if (slave->ctrlr->setup)
 145                 return slave->ctrlr->setup(slave);
 146
 147         return 0;
 148 }