drivers/fpga/lattice-sysconfig-spi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Lattice FPGA programming over slave SPI sysCONFIG interface.
   4  */
   5
   6 #include <linux/of.h>
   7 #include <linux/spi/spi.h>
   8
   9 #include "lattice-sysconfig.h"
  10
  11 static const u32 ecp5_spi_max_speed_hz = 60000000;
  12
  13 static int sysconfig_spi_cmd_transfer(struct sysconfig_priv *priv,
  14                                       const void *tx_buf, size_t tx_len,
  15                                       void *rx_buf, size_t rx_len)
  16 {
  17         struct spi_device *spi = to_spi_device(priv->dev);
  18
  19         return spi_write_then_read(spi, tx_buf, tx_len, rx_buf, rx_len);
  20 }
  21
  22 static int sysconfig_spi_bitstream_burst_init(struct sysconfig_priv *priv)
  23 {
  24         const u8 lsc_bitstream_burst[] = SYSCONFIG_LSC_BITSTREAM_BURST;
  25         struct spi_device *spi = to_spi_device(priv->dev);
  26         struct spi_transfer xfer = {};
  27         struct spi_message msg;
  28         size_t buf_len;
  29         void *buf;
  30         int ret;
  31
  32         buf_len = sizeof(lsc_bitstream_burst);
  33
  34         buf = kmemdup(lsc_bitstream_burst, buf_len, GFP_KERNEL);
  35         if (!buf)
  36                 return -ENOMEM;
  37
  38         xfer.len = buf_len;
  39         xfer.tx_buf = buf;
  40         xfer.cs_change = 1;
  41
  42         spi_message_init_with_transfers(&msg, &xfer, 1);
  43
  44         /*
  45          * Lock SPI bus for exclusive usage until FPGA programming is done.
  46          * SPI bus will be released in sysconfig_spi_bitstream_burst_complete().
  47          */
  48         spi_bus_lock(spi->controller);
  49
  50         ret = spi_sync_locked(spi, &msg);
  51         if (ret)
  52                 spi_bus_unlock(spi->controller);
  53
  54         kfree(buf);
  55
  56         return ret;
  57 }
  58
  59 static int sysconfig_spi_bitstream_burst_write(struct sysconfig_priv *priv,
  60                                                const char *buf, size_t len)
  61 {
  62         struct spi_device *spi = to_spi_device(priv->dev);
  63         struct spi_transfer xfer = {
  64                 .tx_buf = buf,
  65                 .len = len,
  66                 .cs_change = 1,
  67         };
  68         struct spi_message msg;
  69
  70         spi_message_init_with_transfers(&msg, &xfer, 1);
  71
  72         return spi_sync_locked(spi, &msg);
  73 }
  74
  75 static int sysconfig_spi_bitstream_burst_complete(struct sysconfig_priv *priv)
  76 {
  77         struct spi_device *spi = to_spi_device(priv->dev);
  78
  79         /* Bitstream burst write is done, release SPI bus */
  80         spi_bus_unlock(spi->controller);
  81
  82         /* Toggle CS to finish bitstream write */
  83         return spi_write(spi, NULL, 0);
  84 }
  85
  86 static int sysconfig_spi_probe(struct spi_device *spi)
  87 {
  88         const struct spi_device_id *dev_id;
  89         struct device *dev = &spi->dev;
  90         struct sysconfig_priv *priv;
  91         const u32 *spi_max_speed;
  92
  93         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  94         if (!priv)
  95                 return -ENOMEM;
  96
  97         spi_max_speed = device_get_match_data(dev);
  98         if (!spi_max_speed) {
  99                 dev_id = spi_get_device_id(spi);
 100                 if (!dev_id)
 101                         return -ENODEV;
 102
 103                 spi_max_speed = (const u32 *)dev_id->driver_data;
 104         }
 105
 106         if (!spi_max_speed)
 107                 return -EINVAL;
 108
 109         if (spi->max_speed_hz > *spi_max_speed) {
 110                 dev_err(dev, "SPI speed %u is too high, maximum speed is %u\n",
 111                         spi->max_speed_hz, *spi_max_speed);
 112                 return -EINVAL;
 113         }
 114
 115         priv->dev = dev;
 116         priv->command_transfer = sysconfig_spi_cmd_transfer;
 117         priv->bitstream_burst_write_init = sysconfig_spi_bitstream_burst_init;
 118         priv->bitstream_burst_write = sysconfig_spi_bitstream_burst_write;
 119         priv->bitstream_burst_write_complete = sysconfig_spi_bitstream_burst_complete;
 120
 121         return sysconfig_probe(priv);
 122 }
 123
 124 static const struct spi_device_id sysconfig_spi_ids[] = {
 125         {
 126                 .name = "sysconfig-ecp5",
 127                 .driver_data = (kernel_ulong_t)&ecp5_spi_max_speed_hz,
 128         }, {},
 129 };
 130 MODULE_DEVICE_TABLE(spi, sysconfig_spi_ids);
 131
 132 #if IS_ENABLED(CONFIG_OF)
 133 static const struct of_device_id sysconfig_of_ids[] = {
 134         {
 135                 .compatible = "lattice,sysconfig-ecp5",
 136                 .data = &ecp5_spi_max_speed_hz,
 137         }, {},
 138 };
 139 MODULE_DEVICE_TABLE(of, sysconfig_of_ids);
 140 #endif /* IS_ENABLED(CONFIG_OF) */
 141
 142 static struct spi_driver lattice_sysconfig_driver = {
 143         .probe = sysconfig_spi_probe,
 144         .id_table = sysconfig_spi_ids,
 145         .driver = {
 146                 .name = "lattice_sysconfig_spi_fpga_mgr",
 147                 .of_match_table = of_match_ptr(sysconfig_of_ids),
 148         },
 149 };
 150 module_spi_driver(lattice_sysconfig_driver);
 151
 152 MODULE_DESCRIPTION("Lattice sysCONFIG Slave SPI FPGA Manager");
 153 MODULE_LICENSE("GPL");