nvmem: add driver for Layerscape SFP (Security Fuse Processor)

Add support for the Security Fuse Processor found on Layerscape SoCs.
This driver implements basic read access.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220220151527.17216-10-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index da41461..4063ea1 100644 (file)
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -300,4 +300,16 @@ config NVMEM_BRCM_NVRAM
          This driver provides support for Broadcom's NVRAM that can be accessed
          using I/O mapping.
 
+config NVMEM_LAYERSCAPE_SFP
+       tristate "Layerscape SFP (Security Fuse Processor) support"
+       depends on ARCH_LAYERSCAPE || COMPILE_TEST
+       depends on HAS_IOMEM
+       help
+         This driver provides support to read the eFuses on Freescale
+         Layerscape SoC's. For example, the vendor provides a per part
+         unique ID there.
+
+         This driver can also be built as a module. If so, the module
+         will be called layerscape-sfp.
+
 endif

diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index dcbbde3..d4e1052 100644 (file)
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -61,3 +61,5 @@ obj-$(CONFIG_NVMEM_RMEM)      += nvmem-rmem.o
 nvmem-rmem-y                   := rmem.o
 obj-$(CONFIG_NVMEM_BRCM_NVRAM) += nvmem_brcm_nvram.o
 nvmem_brcm_nvram-y             := brcm_nvram.o
+obj-$(CONFIG_NVMEM_LAYERSCAPE_SFP)     += nvmem-layerscape-sfp.o
+nvmem-layerscape-sfp-y         := layerscape-sfp.o

diff --git a/drivers/nvmem/layerscape-sfp.c b/drivers/nvmem/layerscape-sfp.c
new file mode 100644 (file)
index 0000000..e591c15
--- /dev/null
+++ b/drivers/nvmem/layerscape-sfp.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Layerscape SFP driver
+ *
+ * Copyright (c) 2022 Michael Walle <michael@walle.cc>
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define LAYERSCAPE_SFP_OTP_OFFSET      0x0200
+
+struct layerscape_sfp_priv {
+       void __iomem *base;
+};
+
+struct layerscape_sfp_data {
+       int size;
+};
+
+static int layerscape_sfp_read(void *context, unsigned int offset, void *val,
+                              size_t bytes)
+{
+       struct layerscape_sfp_priv *priv = context;
+
+       memcpy_fromio(val, priv->base + LAYERSCAPE_SFP_OTP_OFFSET + offset,
+                     bytes);
+
+       return 0;
+}
+
+static struct nvmem_config layerscape_sfp_nvmem_config = {
+       .name = "fsl-sfp",
+       .reg_read = layerscape_sfp_read,
+};
+
+static int layerscape_sfp_probe(struct platform_device *pdev)
+{
+       const struct layerscape_sfp_data *data;
+       struct layerscape_sfp_priv *priv;
+       struct nvmem_device *nvmem;
+
+       priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+
+       priv->base = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(priv->base))
+               return PTR_ERR(priv->base);
+
+       data = device_get_match_data(&pdev->dev);
+
+       layerscape_sfp_nvmem_config.size = data->size;
+       layerscape_sfp_nvmem_config.dev = &pdev->dev;
+       layerscape_sfp_nvmem_config.priv = priv;
+
+       nvmem = devm_nvmem_register(&pdev->dev, &layerscape_sfp_nvmem_config);
+
+       return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static const struct layerscape_sfp_data ls1028a_data = {
+       .size = 0x88,
+};
+
+static const struct of_device_id layerscape_sfp_dt_ids[] = {
+       { .compatible = "fsl,ls1028a-sfp", .data = &ls1028a_data },
+       {},
+};
+MODULE_DEVICE_TABLE(of, layerscape_sfp_dt_ids);
+
+static struct platform_driver layerscape_sfp_driver = {
+       .probe  = layerscape_sfp_probe,
+       .driver = {
+               .name   = "layerscape_sfp",
+               .of_match_table = layerscape_sfp_dt_ids,
+       },
+};
+module_platform_driver(layerscape_sfp_driver);
+
+MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
+MODULE_DESCRIPTION("Layerscape Security Fuse Processor driver");
+MODULE_LICENSE("GPL");