drivers/spi/mpc8xxx_spi.c

   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  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9
  10 #include <malloc.h>
  11 #include <spi.h>
  12 #include <asm/mpc8xxx_spi.h>
  13
  14 #define SPI_EV_NE       (0x80000000 >> 22)      /* Receiver Not Empty */
  15 #define SPI_EV_NF       (0x80000000 >> 23)      /* Transmitter Not Full */
  16
  17 #define SPI_MODE_LOOP   (0x80000000 >> 1)       /* Loopback mode */
  18 #define SPI_MODE_REV    (0x80000000 >> 5)       /* Reverse mode - MSB first */
  19 #define SPI_MODE_MS     (0x80000000 >> 6)       /* Always master */
  20 #define SPI_MODE_EN     (0x80000000 >> 7)       /* Enable interface */
  21
  22 #define SPI_TIMEOUT     1000
  23
  24 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  25                 unsigned int max_hz, unsigned int mode)
  26 {
  27         struct spi_slave *slave;
  28
  29         if (!spi_cs_is_valid(bus, cs))
  30                 return NULL;
  31
  32         slave = spi_alloc_slave_base(bus, cs);
  33         if (!slave)
  34                 return NULL;
  35
  36         /*
  37          * TODO: Some of the code in spi_init() should probably move
  38          * here, or into spi_claim_bus() below.
  39          */
  40
  41         return slave;
  42 }
  43
  44 void spi_free_slave(struct spi_slave *slave)
  45 {
  46         free(slave);
  47 }
  48
  49 void spi_init(void)
  50 {
  51         volatile spi8xxx_t *spi = &((immap_t *) (CONFIG_SYS_IMMR))->spi;
  52
  53         /*
  54          * SPI pins on the MPC83xx are not muxed, so all we do is initialize
  55          * some registers
  56          */
  57         spi->mode = SPI_MODE_REV | SPI_MODE_MS | SPI_MODE_EN;
  58         spi->mode = (spi->mode & 0xfff0ffff) | (1 << 16); /* Use SYSCLK / 8
  59                                                              (16.67MHz typ.) */
  60         spi->event = 0xffffffff;        /* Clear all SPI events */
  61         spi->mask = 0x00000000; /* Mask  all SPI interrupts */
  62         spi->com = 0;           /* LST bit doesn't do anything, so disregard */
  63 }
  64
  65 int spi_claim_bus(struct spi_slave *slave)
  66 {
  67         return 0;
  68 }
  69
  70 void spi_release_bus(struct spi_slave *slave)
  71 {
  72
  73 }
  74
  75 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
  76                 void *din, unsigned long flags)
  77 {
  78         volatile spi8xxx_t *spi = &((immap_t *) (CONFIG_SYS_IMMR))->spi;
  79         unsigned int tmpdout, tmpdin, event;
  80         int numBlks = DIV_ROUND_UP(bitlen, 32);
  81         int tm, isRead = 0;
  82         unsigned char charSize = 32;
  83
  84         debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
  85               slave->bus, slave->cs, *(uint *) dout, *(uint *) din, bitlen);
  86
  87         if (flags & SPI_XFER_BEGIN)
  88                 spi_cs_activate(slave);
  89
  90         spi->event = 0xffffffff;        /* Clear all SPI events */
  91
  92         /* handle data in 32-bit chunks */
  93         while (numBlks--) {
  94                 tmpdout = 0;
  95                 charSize = (bitlen >= 32 ? 32 : bitlen);
  96
  97                 /* Shift data so it's msb-justified */
  98                 tmpdout = *(u32 *) dout >> (32 - charSize);
  99
 100                 /* The LEN field of the SPMODE register is set as follows:
 101                  *
 102                  * Bit length             setting
 103                  * len <= 4               3
 104                  * 4 < len <= 16          len - 1
 105                  * len > 16               0
 106                  */
 107
 108                 spi->mode &= ~SPI_MODE_EN;
 109
 110                 if (bitlen <= 16) {
 111                         if (bitlen <= 4)
 112                                 spi->mode = (spi->mode & 0xff0fffff) |
 113                                             (3 << 20);
 114                         else
 115                                 spi->mode = (spi->mode & 0xff0fffff) |
 116                                             ((bitlen - 1) << 20);
 117                 } else {
 118                         spi->mode = (spi->mode & 0xff0fffff);
 119                         /* Set up the next iteration if sending > 32 bits */
 120                         bitlen -= 32;
 121                         dout += 4;
 122                 }
 123
 124                 spi->mode |= SPI_MODE_EN;
 125
 126                 spi->tx = tmpdout;      /* Write the data out */
 127                 debug("*** spi_xfer: ... %08x written\n", tmpdout);
 128
 129                 /*
 130                  * Wait for SPI transmit to get out
 131                  * or time out (1 second = 1000 ms)
 132                  * The NE event must be read and cleared first
 133                  */
 134                 for (tm = 0, isRead = 0; tm < SPI_TIMEOUT; ++tm) {
 135                         event = spi->event;
 136                         if (event & SPI_EV_NE) {
 137                                 tmpdin = spi->rx;
 138                                 spi->event |= SPI_EV_NE;
 139                                 isRead = 1;
 140
 141                                 *(u32 *) din = (tmpdin << (32 - charSize));
 142                                 if (charSize == 32) {
 143                                         /* Advance output buffer by 32 bits */
 144                                         din += 4;
 145                                 }
 146                         }
 147                         /*
 148                          * Only bail when we've had both NE and NF events.
 149                          * This will cause timeouts on RO devices, so maybe
 150                          * in the future put an arbitrary delay after writing
 151                          * the device.  Arbitrary delays suck, though...
 152                          */
 153                         if (isRead && (event & SPI_EV_NF))
 154                                 break;
 155                 }
 156                 if (tm >= SPI_TIMEOUT)
 157                         puts("*** spi_xfer: Time out during SPI transfer");
 158
 159                 debug("*** spi_xfer: transfer ended. Value=%08x\n", tmpdin);
 160         }
 161
 162         if (flags & SPI_XFER_END)
 163                 spi_cs_deactivate(slave);
 164
 165         return 0;
 166 }