vexpress_config.c 3.0 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130
  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright (C) 2018 Arm Ltd
  4. * Author: Liviu Dudau <liviu.dudau@foss.arm.com>
  5. *
  6. */
  7. #include <common.h>
  8. #include <dm.h>
  9. #include <malloc.h>
  10. #include <dm/read.h>
  11. #include <asm/io.h>
  12. #include <linux/bitops.h>
  13. #include <linux/delay.h>
  14. #include <misc.h>
  15. #define SYS_CFGDATA 0xa0
  16. #define SYS_CFGCTRL 0xa4
  17. #define SYS_CFGCTRL_START BIT(31)
  18. #define SYS_CFGCTRL_WRITE BIT(30)
  19. #define SYS_CFGSTAT 0xa8
  20. #define SYS_CFGSTAT_ERR BIT(1)
  21. #define SYS_CFGSTAT_COMPLETE BIT(0)
  22. struct vexpress_config_sysreg {
  23. phys_addr_t addr;
  24. u32 site;
  25. };
  26. static int vexpress_config_exec(struct vexpress_config_sysreg *syscfg,
  27. bool write, void *buf, int size)
  28. {
  29. u32 cmd, status, tries = 100;
  30. cmd = (*(u32 *)buf) | SYS_CFGCTRL_START | (syscfg->site << 16);
  31. if (!write) {
  32. /* write a canary in the data register for reads */
  33. writel(0xdeadbeef, syscfg->addr + SYS_CFGDATA);
  34. } else {
  35. cmd |= SYS_CFGCTRL_WRITE;
  36. writel(((u32 *)buf)[1], syscfg->addr + SYS_CFGDATA);
  37. }
  38. writel(0, syscfg->addr + SYS_CFGSTAT);
  39. writel(cmd, syscfg->addr + SYS_CFGCTRL);
  40. /* completion of command takes ages, go to sleep (150us) */
  41. do {
  42. udelay(150);
  43. status = readl(syscfg->addr + SYS_CFGSTAT);
  44. if (status & SYS_CFGSTAT_ERR)
  45. return -EFAULT;
  46. } while (--tries && !(status & SYS_CFGSTAT_COMPLETE));
  47. if (!tries)
  48. return -ETIMEDOUT;
  49. if (!write)
  50. (*(u32 *)buf) = readl(syscfg->addr + SYS_CFGDATA);
  51. return 0;
  52. }
  53. static int vexpress_config_read(struct udevice *dev,
  54. int offset, void *buf, int size)
  55. {
  56. struct vexpress_config_sysreg *priv = dev_get_uclass_priv(dev);
  57. if (size != sizeof(u32))
  58. return -EINVAL;
  59. return vexpress_config_exec(priv, false, buf, size);
  60. }
  61. static int vexpress_config_write(struct udevice *dev,
  62. int offset, const void *buf, int size)
  63. {
  64. struct vexpress_config_sysreg *priv = dev_get_uclass_priv(dev);
  65. if (size != sizeof(u32) * 2)
  66. return -EINVAL;
  67. return vexpress_config_exec(priv, true, (void *)buf, size);
  68. }
  69. static struct misc_ops vexpress_config_ops = {
  70. .read = vexpress_config_read,
  71. .write = vexpress_config_write,
  72. };
  73. static int vexpress_config_probe(struct udevice *dev)
  74. {
  75. struct ofnode_phandle_args args;
  76. struct vexpress_config_sysreg *priv;
  77. const char *prop;
  78. int err, prop_size;
  79. err = dev_read_phandle_with_args(dev, "arm,vexpress,config-bridge",
  80. NULL, 0, 0, &args);
  81. if (err)
  82. return err;
  83. prop = ofnode_get_property(args.node, "compatible", &prop_size);
  84. if (!prop || (strncmp(prop, "arm,vexpress-sysreg", 19) != 0))
  85. return -ENOENT;
  86. priv = calloc(1, sizeof(*priv));
  87. if (!priv)
  88. return -ENOMEM;
  89. dev_get_uclass_priv(dev) = priv;
  90. priv->addr = ofnode_get_addr(args.node);
  91. return dev_read_u32(dev, "arm,vexpress,site", &priv->site);
  92. }
  93. static const struct udevice_id vexpress_config_ids[] = {
  94. { .compatible = "arm,vexpress,config-bus" },
  95. { }
  96. };
  97. U_BOOT_DRIVER(vexpress_config_drv) = {
  98. .name = "vexpress_config_bus",
  99. .id = UCLASS_MISC,
  100. .of_match = vexpress_config_ids,
  101. .bind = dm_scan_fdt_dev,
  102. .probe = vexpress_config_probe,
  103. .ops = &vexpress_config_ops,
  104. };