drivers/fpga/ts73xx-fpga.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Technologic Systems TS-73xx SBC FPGA loader
   4  *
   5  * Copyright (C) 2016 Florian Fainelli <f.fainelli@gmail.com>
   6  *
   7  * FPGA Manager Driver for the on-board Altera Cyclone II FPGA found on
   8  * TS-7300, heavily based on load_fpga.c in their vendor tree.
   9  */
  10
  11 #include <linux/delay.h>
  12 #include <linux/io.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/string.h>
  16 #include <linux/iopoll.h>
  17 #include <linux/fpga/fpga-mgr.h>
  18
  19 #define TS73XX_FPGA_DATA_REG            0
  20 #define TS73XX_FPGA_CONFIG_REG          1
  21
  22 #define TS73XX_FPGA_WRITE_DONE          0x1
  23 #define TS73XX_FPGA_WRITE_DONE_TIMEOUT  1000    /* us */
  24 #define TS73XX_FPGA_RESET               0x2
  25 #define TS73XX_FPGA_RESET_LOW_DELAY     30      /* us */
  26 #define TS73XX_FPGA_RESET_HIGH_DELAY    80      /* us */
  27 #define TS73XX_FPGA_LOAD_OK             0x4
  28 #define TS73XX_FPGA_CONFIG_LOAD         0x8
  29
  30 struct ts73xx_fpga_priv {
  31         void __iomem    *io_base;
  32         struct device   *dev;
  33 };
  34
  35 static int ts73xx_fpga_write_init(struct fpga_manager *mgr,
  36                                   struct fpga_image_info *info,
  37                                   const char *buf, size_t count)
  38 {
  39         struct ts73xx_fpga_priv *priv = mgr->priv;
  40
  41         /* Reset the FPGA */
  42         writeb(0, priv->io_base + TS73XX_FPGA_CONFIG_REG);
  43         udelay(TS73XX_FPGA_RESET_LOW_DELAY);
  44         writeb(TS73XX_FPGA_RESET, priv->io_base + TS73XX_FPGA_CONFIG_REG);
  45         udelay(TS73XX_FPGA_RESET_HIGH_DELAY);
  46
  47         return 0;
  48 }
  49
  50 static int ts73xx_fpga_write(struct fpga_manager *mgr, const char *buf,
  51                              size_t count)
  52 {
  53         struct ts73xx_fpga_priv *priv = mgr->priv;
  54         size_t i = 0;
  55         int ret;
  56         u8 reg;
  57
  58         while (count--) {
  59                 ret = readb_poll_timeout(priv->io_base + TS73XX_FPGA_CONFIG_REG,
  60                                          reg, !(reg & TS73XX_FPGA_WRITE_DONE),
  61                                          1, TS73XX_FPGA_WRITE_DONE_TIMEOUT);
  62                 if (ret < 0)
  63                         return ret;
  64
  65                 writeb(buf[i], priv->io_base + TS73XX_FPGA_DATA_REG);
  66                 i++;
  67         }
  68
  69         return 0;
  70 }
  71
  72 static int ts73xx_fpga_write_complete(struct fpga_manager *mgr,
  73                                       struct fpga_image_info *info)
  74 {
  75         struct ts73xx_fpga_priv *priv = mgr->priv;
  76         u8 reg;
  77
  78         usleep_range(1000, 2000);
  79         reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
  80         reg |= TS73XX_FPGA_CONFIG_LOAD;
  81         writeb(reg, priv->io_base + TS73XX_FPGA_CONFIG_REG);
  82
  83         usleep_range(1000, 2000);
  84         reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
  85         reg &= ~TS73XX_FPGA_CONFIG_LOAD;
  86         writeb(reg, priv->io_base + TS73XX_FPGA_CONFIG_REG);
  87
  88         reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
  89         if ((reg & TS73XX_FPGA_LOAD_OK) != TS73XX_FPGA_LOAD_OK)
  90                 return -ETIMEDOUT;
  91
  92         return 0;
  93 }
  94
  95 static const struct fpga_manager_ops ts73xx_fpga_ops = {
  96         .write_init     = ts73xx_fpga_write_init,
  97         .write          = ts73xx_fpga_write,
  98         .write_complete = ts73xx_fpga_write_complete,
  99 };
 100
 101 static int ts73xx_fpga_probe(struct platform_device *pdev)
 102 {
 103         struct device *kdev = &pdev->dev;
 104         struct ts73xx_fpga_priv *priv;
 105         struct fpga_manager *mgr;
 106
 107         priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL);
 108         if (!priv)
 109                 return -ENOMEM;
 110
 111         priv->dev = kdev;
 112
 113         priv->io_base = devm_platform_ioremap_resource(pdev, 0);
 114         if (IS_ERR(priv->io_base))
 115                 return PTR_ERR(priv->io_base);
 116
 117         mgr = devm_fpga_mgr_register(kdev, "TS-73xx FPGA Manager",
 118                                      &ts73xx_fpga_ops, priv);
 119         return PTR_ERR_OR_ZERO(mgr);
 120 }
 121
 122 static struct platform_driver ts73xx_fpga_driver = {
 123         .driver = {
 124                 .name   = "ts73xx-fpga-mgr",
 125         },
 126         .probe  = ts73xx_fpga_probe,
 127 };
 128 module_platform_driver(ts73xx_fpga_driver);
 129
 130 MODULE_AUTHOR("Florian Fainelli <f.fainelli@gmail.com>");
 131 MODULE_DESCRIPTION("TS-73xx FPGA Manager driver");
 132 MODULE_LICENSE("GPL v2");