drivers/fpga/xilinx-spi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Xilinx Spartan6 and 7 Series Slave Serial SPI Driver
   4  *
   5  * Copyright (C) 2017 DENX Software Engineering
   6  *
   7  * Anatolij Gustschin <[email protected]>
   8  *
   9  * Manage Xilinx FPGA firmware that is loaded over SPI using
  10  * the slave serial configuration interface.
  11  */
  12
  13 #include "xilinx-core.h"
  14
  15 #include <linux/module.h>
  16 #include <linux/mod_devicetable.h>
  17 #include <linux/of.h>
  18 #include <linux/spi/spi.h>
  19
  20 static int xilinx_spi_write(struct xilinx_fpga_core *core, const char *buf,
  21                             size_t count)
  22 {
  23         struct spi_device *spi = to_spi_device(core->dev);
  24         const char *fw_data = buf;
  25         const char *fw_data_end = fw_data + count;
  26
  27         while (fw_data < fw_data_end) {
  28                 size_t remaining, stride;
  29                 int ret;
  30
  31                 remaining = fw_data_end - fw_data;
  32                 stride = min_t(size_t, remaining, SZ_4K);
  33
  34                 ret = spi_write(spi, fw_data, stride);
  35                 if (ret) {
  36                         dev_err(core->dev, "SPI error in firmware write: %d\n",
  37                                 ret);
  38                         return ret;
  39                 }
  40                 fw_data += stride;
  41         }
  42
  43         return 0;
  44 }
  45
  46 static int xilinx_spi_probe(struct spi_device *spi)
  47 {
  48         struct xilinx_fpga_core *core;
  49
  50         core = devm_kzalloc(&spi->dev, sizeof(*core), GFP_KERNEL);
  51         if (!core)
  52                 return -ENOMEM;
  53
  54         core->dev = &spi->dev;
  55         core->write = xilinx_spi_write;
  56
  57         return xilinx_core_probe(core);
  58 }
  59
  60 #ifdef CONFIG_OF
  61 static const struct of_device_id xlnx_spi_of_match[] = {
  62         {
  63                 .compatible = "xlnx,fpga-slave-serial",
  64         },
  65         {}
  66 };
  67 MODULE_DEVICE_TABLE(of, xlnx_spi_of_match);
  68 #endif
  69
  70 static struct spi_driver xilinx_slave_spi_driver = {
  71         .driver = {
  72                 .name = "xlnx-slave-spi",
  73                 .of_match_table = of_match_ptr(xlnx_spi_of_match),
  74         },
  75         .probe = xilinx_spi_probe,
  76 };
  77
  78 module_spi_driver(xilinx_slave_spi_driver)
  79
  80 MODULE_LICENSE("GPL v2");
  81 MODULE_AUTHOR("Anatolij Gustschin <[email protected]>");
  82 MODULE_DESCRIPTION("Load Xilinx FPGA firmware over SPI");