drivers/fpga/ts73xx-fpga.c

   1 /*
   2  * Technologic Systems TS-73xx SBC FPGA loader
   3  *
   4  * Copyright (C) 2016 Florian Fainelli <f.fainelli@gmail.com>
   5  *
   6  * FPGA Manager Driver for the on-board Altera Cyclone II FPGA found on
   7  * TS-7300, heavily based on load_fpga.c in their vendor tree.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; version 2 of the License.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/delay.h>
  20 #include <linux/io.h>
  21 #include <linux/module.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/string.h>
  24 #include <linux/iopoll.h>
  25 #include <linux/fpga/fpga-mgr.h>
  26
  27 #define TS73XX_FPGA_DATA_REG            0
  28 #define TS73XX_FPGA_CONFIG_REG          1
  29
  30 #define TS73XX_FPGA_WRITE_DONE          0x1
  31 #define TS73XX_FPGA_WRITE_DONE_TIMEOUT  1000    /* us */
  32 #define TS73XX_FPGA_RESET               0x2
  33 #define TS73XX_FPGA_RESET_LOW_DELAY     30      /* us */
  34 #define TS73XX_FPGA_RESET_HIGH_DELAY    80      /* us */
  35 #define TS73XX_FPGA_LOAD_OK             0x4
  36 #define TS73XX_FPGA_CONFIG_LOAD         0x8
  37
  38 struct ts73xx_fpga_priv {
  39         void __iomem    *io_base;
  40         struct device   *dev;
  41 };
  42
  43 static enum fpga_mgr_states ts73xx_fpga_state(struct fpga_manager *mgr)
  44 {
  45         return FPGA_MGR_STATE_UNKNOWN;
  46 }
  47
  48 static int ts73xx_fpga_write_init(struct fpga_manager *mgr,
  49                                   struct fpga_image_info *info,
  50                                   const char *buf, size_t count)
  51 {
  52         struct ts73xx_fpga_priv *priv = mgr->priv;
  53
  54         /* Reset the FPGA */
  55         writeb(0, priv->io_base + TS73XX_FPGA_CONFIG_REG);
  56         udelay(TS73XX_FPGA_RESET_LOW_DELAY);
  57         writeb(TS73XX_FPGA_RESET, priv->io_base + TS73XX_FPGA_CONFIG_REG);
  58         udelay(TS73XX_FPGA_RESET_HIGH_DELAY);
  59
  60         return 0;
  61 }
  62
  63 static int ts73xx_fpga_write(struct fpga_manager *mgr, const char *buf,
  64                              size_t count)
  65 {
  66         struct ts73xx_fpga_priv *priv = mgr->priv;
  67         size_t i = 0;
  68         int ret;
  69         u8 reg;
  70
  71         while (count--) {
  72                 ret = readb_poll_timeout(priv->io_base + TS73XX_FPGA_CONFIG_REG,
  73                                          reg, !(reg & TS73XX_FPGA_WRITE_DONE),
  74                                          1, TS73XX_FPGA_WRITE_DONE_TIMEOUT);
  75                 if (ret < 0)
  76                         return ret;
  77
  78                 writeb(buf[i], priv->io_base + TS73XX_FPGA_DATA_REG);
  79                 i++;
  80         }
  81
  82         return 0;
  83 }
  84
  85 static int ts73xx_fpga_write_complete(struct fpga_manager *mgr,
  86                                       struct fpga_image_info *info)
  87 {
  88         struct ts73xx_fpga_priv *priv = mgr->priv;
  89         u8 reg;
  90
  91         usleep_range(1000, 2000);
  92         reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
  93         reg |= TS73XX_FPGA_CONFIG_LOAD;
  94         writeb(reg, priv->io_base + TS73XX_FPGA_CONFIG_REG);
  95
  96         usleep_range(1000, 2000);
  97         reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
  98         reg &= ~TS73XX_FPGA_CONFIG_LOAD;
  99         writeb(reg, priv->io_base + TS73XX_FPGA_CONFIG_REG);
 100
 101         reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
 102         if ((reg & TS73XX_FPGA_LOAD_OK) != TS73XX_FPGA_LOAD_OK)
 103                 return -ETIMEDOUT;
 104
 105         return 0;
 106 }
 107
 108 static const struct fpga_manager_ops ts73xx_fpga_ops = {
 109         .state          = ts73xx_fpga_state,
 110         .write_init     = ts73xx_fpga_write_init,
 111         .write          = ts73xx_fpga_write,
 112         .write_complete = ts73xx_fpga_write_complete,
 113 };
 114
 115 static int ts73xx_fpga_probe(struct platform_device *pdev)
 116 {
 117         struct device *kdev = &pdev->dev;
 118         struct ts73xx_fpga_priv *priv;
 119         struct resource *res;
 120
 121         priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL);
 122         if (!priv)
 123                 return -ENOMEM;
 124
 125         priv->dev = kdev;
 126
 127         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 128         priv->io_base = devm_ioremap_resource(kdev, res);
 129         if (IS_ERR(priv->io_base)) {
 130                 dev_err(kdev, "unable to remap registers\n");
 131                 return PTR_ERR(priv->io_base);
 132         }
 133
 134         return fpga_mgr_register(kdev, "TS-73xx FPGA Manager",
 135                                  &ts73xx_fpga_ops, priv);
 136 }
 137
 138 static int ts73xx_fpga_remove(struct platform_device *pdev)
 139 {
 140         fpga_mgr_unregister(&pdev->dev);
 141
 142         return 0;
 143 }
 144
 145 static struct platform_driver ts73xx_fpga_driver = {
 146         .driver = {
 147                 .name   = "ts73xx-fpga-mgr",
 148         },
 149         .probe  = ts73xx_fpga_probe,
 150         .remove = ts73xx_fpga_remove,
 151 };
 152 module_platform_driver(ts73xx_fpga_driver);
 153
 154 MODULE_AUTHOR("Florian Fainelli <f.fainelli@gmail.com>");
 155 MODULE_DESCRIPTION("TS-73xx FPGA Manager driver");
 156 MODULE_LICENSE("GPL v2");