[PATCH v1 2/3] nvmem: add driver for Layerscape SFP (Security Fuse Processor)

From: Michael Walle
Date: Thu Jan 27 2022 - 11:38:00 EST


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

Signed-off-by: Michael Walle <michael@xxxxxxxx>
---
drivers/nvmem/Kconfig | 12 +++++
drivers/nvmem/Makefile | 2 +
drivers/nvmem/layerscape-sfp.c | 91 ++++++++++++++++++++++++++++++++++
3 files changed, 105 insertions(+)
create mode 100644 drivers/nvmem/layerscape-sfp.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 94dd60b2654e..63792082e476 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -307,4 +307,16 @@ 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 4e6d877fdfaf..914358fcdb37 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -62,3 +62,5 @@ 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
index 000000000000..4aa94e03d8d1
--- /dev/null
+++ b/drivers/nvmem/layerscape-sfp.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Layerscape SFP driver
+ *
+ * Copyright (c) 2022 Michael Walle <michael@xxxxxxxx>
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/delay.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@xxxxxxxx>");
+MODULE_DESCRIPTION("Layerscape Security Fuse Processor driver");
+MODULE_LICENSE("GPL v2");
--
2.30.2