target/linux/bcm53xx/patches-5.4/181-0002-firmware-bcm47xx_nvram-support-platform-device-brcm-.patch

   1 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   2 Date: Tue, 2 Mar 2021 08:33:13 +0100
   3 Subject: [PATCH] firmware: bcm47xx_nvram: support platform device "brcm,nvram"
   4
   5 Add support for platform device providing mapping resource. This allows
   6 reading NVRAM based on DT mapping binding. It's required for devices
   7 that boot depending on NVRAM stored setup and provides early access to
   8 NVRAM data.
   9
  10 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  11 ---
  12  drivers/firmware/broadcom/bcm47xx_nvram.c | 55 +++++++++++++++++++++++
  13  1 file changed, 55 insertions(+)
  14
  15 --- a/drivers/firmware/broadcom/bcm47xx_nvram.c
  16 +++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
  17 @@ -13,6 +13,7 @@
  18  #include <linux/kernel.h>
  19  #include <linux/string.h>
  20  #include <linux/mtd/mtd.h>
  21 +#include <linux/platform_device.h>
  22  #include <linux/bcm47xx_nvram.h>
  23
  24  #define NVRAM_MAGIC                    0x48534C46      /* 'FLSH' */
  25 @@ -162,6 +163,60 @@ static int nvram_init(void)
  26         return -ENXIO;
  27  }
  28
  29 +static int brcm_nvram_probe(struct platform_device *pdev)
  30 +{
  31 +       struct nvram_header __iomem *header;
  32 +       struct device *dev = &pdev->dev;
  33 +       struct resource *res;
  34 +       void __iomem *mmio;
  35 +       size_t copy_len;
  36 +
  37 +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  38 +       if (!res) {
  39 +               dev_err(dev, "Failed to get resource\n");
  40 +               return -ENODEV;
  41 +       }
  42 +
  43 +       mmio = ioremap(res->start, resource_size(res));
  44 +       if (!mmio)
  45 +               return -ENOMEM;
  46 +
  47 +       header = (struct nvram_header *)mmio;
  48 +       copy_len = DIV_ROUND_UP(sizeof(*header) + header->len, 4);
  49 +       if (header->magic != NVRAM_MAGIC) {
  50 +               dev_err(dev, "No NVRAM found at %pR\n", res);
  51 +               return -EPROTO;
  52 +       } else if (copy_len > resource_size(res)) {
  53 +               dev_err(dev, "NVRAM size exceeds %pR\n", res);
  54 +               return -ERANGE;
  55 +       } else if (copy_len >= NVRAM_SPACE) {
  56 +               dev_err(dev, "NVRAM size exceeds buffer size %d\n", NVRAM_SPACE);
  57 +               return -ENOMEM;
  58 +       }
  59 +
  60 +       __ioread32_copy(nvram_buf, mmio, copy_len);
  61 +       nvram_buf[NVRAM_SPACE - 1] = '\0';
  62 +
  63 +       iounmap(mmio);
  64 +
  65 +       return 0;
  66 +}
  67 +
  68 +static const struct of_device_id brcm_nvram_of_match[] = {
  69 +       { .compatible = "brcm,nvram "},
  70 +       {},
  71 +};
  72 +
  73 +static struct platform_driver brcm_nvram_driver = {
  74 +       .driver = {
  75 +               .name = "brcm_nvram",
  76 +               .of_match_table = brcm_nvram_of_match,
  77 +       },
  78 +       .probe  = brcm_nvram_probe,
  79 +};
  80 +
  81 +module_platform_driver(brcm_nvram_driver);
  82 +
  83  int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
  84  {
  85         char *var, *value, *end, *eq;