These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / drivers / nvmem / sunxi_sid.c

diff --git a/kernel/drivers/nvmem/sunxi_sid.c b/kernel/drivers/nvmem/sunxi_sid.c
new file mode 100644 (file)
index 0000000..cfa3b85
--- /dev/null
+++ b/kernel/drivers/nvmem/sunxi_sid.c
@@ -0,0 +1,180 @@
+/*
+ * Allwinner sunXi SoCs Security ID support.
+ *
+ * Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl>
+ * Copyright (C) 2014 Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+
+
+static struct nvmem_config econfig = {
+       .name = "sunxi-sid",
+       .read_only = true,
+       .owner = THIS_MODULE,
+};
+
+struct sunxi_sid {
+       void __iomem            *base;
+};
+
+/* We read the entire key, due to a 32 bit read alignment requirement. Since we
+ * want to return the requested byte, this results in somewhat slower code and
+ * uses 4 times more reads as needed but keeps code simpler. Since the SID is
+ * only very rarely probed, this is not really an issue.
+ */
+static u8 sunxi_sid_read_byte(const struct sunxi_sid *sid,
+                             const unsigned int offset)
+{
+       u32 sid_key;
+
+       sid_key = ioread32be(sid->base + round_down(offset, 4));
+       sid_key >>= (offset % 4) * 8;
+
+       return sid_key; /* Only return the last byte */
+}
+
+static int sunxi_sid_read(void *context,
+                           const void *reg, size_t reg_size,
+                           void *val, size_t val_size)
+{
+       struct sunxi_sid *sid = context;
+       unsigned int offset = *(u32 *)reg;
+       u8 *buf = val;
+
+       while (val_size) {
+               *buf++ = sunxi_sid_read_byte(sid, offset);
+               val_size--;
+               offset++;
+       }
+
+       return 0;
+}
+
+static int sunxi_sid_write(void *context, const void *data, size_t count)
+{
+       /* Unimplemented, dummy to keep regmap core happy */
+       return 0;
+}
+
+static struct regmap_bus sunxi_sid_bus = {
+       .read = sunxi_sid_read,
+       .write = sunxi_sid_write,
+       .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
+       .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
+};
+
+static bool sunxi_sid_writeable_reg(struct device *dev, unsigned int reg)
+{
+       return false;
+}
+
+static struct regmap_config sunxi_sid_regmap_config = {
+       .reg_bits = 32,
+       .val_bits = 8,
+       .reg_stride = 1,
+       .writeable_reg = sunxi_sid_writeable_reg,
+};
+
+static int sunxi_sid_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct resource *res;
+       struct nvmem_device *nvmem;
+       struct regmap *regmap;
+       struct sunxi_sid *sid;
+       int ret, i, size;
+       char *randomness;
+
+       sid = devm_kzalloc(dev, sizeof(*sid), GFP_KERNEL);
+       if (!sid)
+               return -ENOMEM;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       sid->base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(sid->base))
+               return PTR_ERR(sid->base);
+
+       size = resource_size(res) - 1;
+       sunxi_sid_regmap_config.max_register = size;
+
+       regmap = devm_regmap_init(dev, &sunxi_sid_bus, sid,
+                                 &sunxi_sid_regmap_config);
+       if (IS_ERR(regmap)) {
+               dev_err(dev, "regmap init failed\n");
+               return PTR_ERR(regmap);
+       }
+
+       econfig.dev = dev;
+       nvmem = nvmem_register(&econfig);
+       if (IS_ERR(nvmem))
+               return PTR_ERR(nvmem);
+
+       randomness = kzalloc(sizeof(u8) * size, GFP_KERNEL);
+       if (!randomness) {
+               ret = -EINVAL;
+               goto err_unreg_nvmem;
+       }
+
+       for (i = 0; i < size; i++)
+               randomness[i] = sunxi_sid_read_byte(sid, i);
+
+       add_device_randomness(randomness, size);
+       kfree(randomness);
+
+       platform_set_drvdata(pdev, nvmem);
+
+       return 0;
+
+err_unreg_nvmem:
+       nvmem_unregister(nvmem);
+       return ret;
+}
+
+static int sunxi_sid_remove(struct platform_device *pdev)
+{
+       struct nvmem_device *nvmem = platform_get_drvdata(pdev);
+
+       return nvmem_unregister(nvmem);
+}
+
+static const struct of_device_id sunxi_sid_of_match[] = {
+       { .compatible = "allwinner,sun4i-a10-sid" },
+       { .compatible = "allwinner,sun7i-a20-sid" },
+       {/* sentinel */},
+};
+MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
+
+static struct platform_driver sunxi_sid_driver = {
+       .probe = sunxi_sid_probe,
+       .remove = sunxi_sid_remove,
+       .driver = {
+               .name = "eeprom-sunxi-sid",
+               .of_match_table = sunxi_sid_of_match,
+       },
+};
+module_platform_driver(sunxi_sid_driver);
+
+MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>");
+MODULE_DESCRIPTION("Allwinner sunxi security id driver");
+MODULE_LICENSE("GPL");