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Subject[PATCH 2/4] nvmem: Add driver for STM32 factory-programmed read only mem
Date
Add a read only nvmem driver for STM32 factory-programmed memory area
(on-chip non-volatile storage).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
drivers/nvmem/Kconfig | 10 ++++++
drivers/nvmem/Makefile | 2 ++
drivers/nvmem/stm32-romem.c | 78 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 90 insertions(+)
create mode 100644 drivers/nvmem/stm32-romem.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 0a7a470e..f398b18 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -113,6 +113,16 @@ config NVMEM_BCM_OCOTP
This driver can also be built as a module. If so, the module
will be called nvmem-bcm-ocotp.

+config NVMEM_STM32_ROMEM
+ tristate "STMicroelectronics STM32 factory-programmed memory support"
+ depends on ARCH_STM32 || COMPILE_TEST
+ help
+ Say y here to enable read-only access for STMicroelectronics STM32
+ factory-programmed memory area.
+
+ This driver can also be built as a module. If so, the module
+ will be called nvmem-stm32-romem.
+
config NVMEM_SUNXI_SID
tristate "Allwinner SoCs SID support"
depends on ARCH_SUNXI
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 4e8c616..e85c946 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -26,6 +26,8 @@ nvmem_qfprom-y := qfprom.o
obj-$(CONFIG_ROCKCHIP_EFUSE) += nvmem_rockchip_efuse.o
nvmem_rockchip_efuse-y := rockchip-efuse.o
obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem_sunxi_sid.o
+nvmem_stm32_romem-y := stm32-romem.o
+obj-$(CONFIG_NVMEM_STM32_ROMEM) += nvmem_stm32_romem.o
nvmem_sunxi_sid-y := sunxi_sid.o
obj-$(CONFIG_UNIPHIER_EFUSE) += nvmem-uniphier-efuse.o
nvmem-uniphier-efuse-y := uniphier-efuse.o
diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
new file mode 100644
index 0000000..dadbcc2
--- /dev/null
+++ b/drivers/nvmem/stm32-romem.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * STM32 Factory-programmed memory read access driver
+ *
+ * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
+ * Author: Fabrice Gasnier <fabrice.gasnier@st.com> for STMicroelectronics.
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of_device.h>
+
+struct stm32_romem_priv {
+ void __iomem *base;
+ struct nvmem_config cfg;
+};
+
+static int stm32_romem_read(void *context, unsigned int offset, void *buf,
+ size_t bytes)
+{
+ struct stm32_romem_priv *priv = context;
+ u8 *buf8 = buf;
+ int i;
+
+ for (i = offset; i < offset + bytes; i++)
+ *buf8++ = readb_relaxed(priv->base + i);
+
+ return 0;
+}
+
+static int stm32_romem_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct stm32_romem_priv *priv;
+ struct resource *res;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ priv->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ priv->cfg.name = "stm32-romem";
+ priv->cfg.read_only = true;
+ priv->cfg.word_size = 1;
+ priv->cfg.stride = 1;
+ priv->cfg.size = resource_size(res);
+ priv->cfg.reg_read = stm32_romem_read;
+ priv->cfg.dev = dev;
+ priv->cfg.priv = priv;
+ priv->cfg.owner = THIS_MODULE;
+
+ return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &priv->cfg));
+}
+
+static const struct of_device_id stm32_romem_of_match[] = {
+ { .compatible = "st,stm32-romem", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, stm32_romem_of_match);
+
+static struct platform_driver stm32_romem_driver = {
+ .probe = stm32_romem_probe,
+ .driver = {
+ .name = "stm32-romem",
+ .of_match_table = of_match_ptr(stm32_romem_of_match),
+ },
+};
+module_platform_driver(stm32_romem_driver);
+
+MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM");
+MODULE_ALIAS("platform:nvmem-stm32-romem");
+MODULE_LICENSE("GPL v2");
--
1.9.1
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