[PATCH] drivers: nvmem: atmel-secumod: New driver for Atmel Secumod nvram.

Finn Thain
2016-05-12T05:06:00Z

On Tue, 10 May 2016, David Mosberger-Tang wrote:

> Signed-off-by: David Mosberger <davidm@egauge.net>
> ---
> .../devicetree/bindings/nvmem/atmel-secumod.txt | 46 ++++++++
> arch/arm/boot/dts/sama5d2.dtsi | 20 ++++
> drivers/nvmem/Kconfig | 7 ++
> drivers/nvmem/Makefile | 2 +
> drivers/nvmem/atmel-secumod.c | 122 +++++++++++++++++++++
> 5 files changed, 197 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/nvmem/atmel-secumod.txt
> create mode 100644 drivers/nvmem/atmel-secumod.c
>
> diff --git a/Documentation/devicetree/bindings/nvmem/atmel-secumod.txt b/Documentation/devicetree/bindings/nvmem/atmel-secumod.txt
> new file mode 100644
> index 0000000..0bb7638
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/nvmem/atmel-secumod.txt
> @@ -0,0 +1,46 @@
> += Atmel Secumod device tree bindings =
> +
> +This binding is intended to represent Atmel's Secumod which is found
> +in SAMA5D2 and perhaps others.
> +
> +Required properties:
> +- compatible: should be "atmel,sama5d2-secumod"
> +- reg: Should contain registers location and length of the RAM, followed
> + by register location and length of the Secumod controller.
> +
> += Data cells =
> +Are child nodes of secumod, bindings of which as described in
> +bindings/nvmem/nvmem.txt
> +
> +Example:
> +
> + secumod at fc040000 {
> + compatible = "atmel,sama5d2-secumod";
> + reg = <0xf8044000 0x1420
> + 0xfc040000 0x4000>;
> + status = "okay";
> +
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + secram_auto_erasable at 0000 {
> + reg = <0x0000 0x1000>;
> + };
> + secram at 1000 {
> + reg = <0x1000 0x400>;
> + };
> + ram at 1400 {
> + reg = <0x1400 0x20>;
> + };
> + };
> +
> += Data consumers =
> +Are device nodes which consume nvmem data cells.
> +
> +For example:
> +
> + ram {
> + ...
> + nvmem-cells = <&ram>;
> + nvmem-cell-names = "calibration";
> + };
> diff --git a/arch/arm/boot/dts/sama5d2.dtsi b/arch/arm/boot/dts/sama5d2.dtsi
> index 78996bd..5856d6a 100644
> --- a/arch/arm/boot/dts/sama5d2.dtsi
> +++ b/arch/arm/boot/dts/sama5d2.dtsi
> @@ -1178,6 +1178,26 @@
> clocks = <&pioA_clk>;
> };
>
> + secumod at fc040000 {
> + compatible = "atmel,sama5d2-secumod";
> + reg = <0xf8044000 0x1420
> + 0xfc040000 0x4000>;
> + status = "okay";
> +
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + secram_auto_erasable at 0000 {
> + reg = <0x0000 0x1000>;
> + };
> + secram at 1000 {
> + reg = <0x1000 0x400>;
> + };
> + ram at 1400 {
> + reg = <0x1400 0x20>;
> + };
> + };
> +
> tdes at fc044000 {
> compatible = "atmel,at91sam9g46-tdes";
> reg = <0xfc044000 0x100>;
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index ca52952..3d34fbb 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -102,4 +102,11 @@ config NVMEM_VF610_OCOTP
> This driver can also be build as a module. If so, the module will
> be called nvmem-vf610-ocotp.
>
> +config NVMEM_ATMEL_SECUMOD
> + tristate "Atmel Secure Module driver"
> + depends on ARCH_AT91
> + help
> + Select this to get support for the secure module (SECUMOD) built
> + into the SAMA5D2 chips.
> +
> endif
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index 45ab1ae..9cbd950 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -22,3 +22,5 @@ obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem_sunxi_sid.o
> nvmem_sunxi_sid-y := sunxi_sid.o
> obj-$(CONFIG_NVMEM_VF610_OCOTP) += nvmem-vf610-ocotp.o
> nvmem-vf610-ocotp-y := vf610-ocotp.o
> +obj-$(CONFIG_NVMEM_ATMEL_SECUMOD) += nvmem-atmel-secumod.o
> +nvmem-atmel-secumod-y := atmel-secumod.o
> diff --git a/drivers/nvmem/atmel-secumod.c b/drivers/nvmem/atmel-secumod.c
> new file mode 100644
> index 0000000..a6b4574
> --- /dev/null
> +++ b/drivers/nvmem/atmel-secumod.c
> @@ -0,0 +1,122 @@
> +/*
> + * Driver for SAMA5D2 secure module (SECUMOD).
> + *
> + * Copyright (C) 2016 eGauge Systems LLC
> + *
> + * David Mosberger <davidm@egauge.net>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +#include <linux/delay.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>
> +
> +static struct regmap_config secumod_regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4
> +};
> +
> +static struct nvmem_config econfig = {
> + .name = "secumod",
> + .owner = THIS_MODULE,
> +};
> +
> +/*
> + * Security-module register definitions:
> + */
> +#define SECUMOD_RAMRDY 0x0014
> +
> +/*
> + * Since the secure module may need to automatically erase some of the
> + * RAM, it may take a while for it to be ready. As far as I know,
> + * it's not documented how long this might take in the worst-case.
> + */
> +static void
> +secumod_wait_ready (void *regs)
> +{
> + unsigned long start, stop;
> +
> + start = jiffies;
> + while (!(readl(regs + SECUMOD_RAMRDY) & 1))
> + msleep_interruptible(1);
> + stop = jiffies;
> + if (stop != start)
> + pr_info("nvmem-atmel-secumod: it took %u msec for SECUMOD "
> + "to become ready...\n", jiffies_to_msecs(stop - start));
> + else
> + pr_info("nvmem-atmel-secumod: ready\n");
> +}
> +
> +static int secumod_remove(struct platform_device *pdev)
> +{
> + struct nvmem_device *nvmem = platform_get_drvdata(pdev);
> +
> + return nvmem_unregister(nvmem);
> +}
> +
> +static int secumod_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct resource *res;
> + struct nvmem_device *nvmem;
> + struct regmap *regmap;
> + void __iomem *base;
> +
> + /*
> + * Map controller address temporarily so we can ensure that
> + * the hardware is ready:
> + */
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> + base = devm_ioremap_resource(dev, res);

I would check IS_ERR(base) here...

> + secumod_wait_ready(base);
> + devm_iounmap(dev, base);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + base = devm_ioremap_resource(dev, res);
> +
> + if (IS_ERR(base))
> + return PTR_ERR(base);

...just like you did here.

When you send v2, you should address it to all of the relevant maintainers
and mailing lists in order to get the necessary Acked-by tags. My tags
aren't useful here. Please see,

$ scripts/get_maintainer.pl this.patch

--

> +
> + secumod_regmap_config.max_register = resource_size(res) - 1;
> +
> + regmap = devm_regmap_init_mmio(dev, base, &secumod_regmap_config);
> + if (IS_ERR(regmap)) {
> + dev_err(dev, "%s: regmap init failed\n", __func__);
> + return PTR_ERR(regmap);
> + }
> + econfig.dev = dev;
> + nvmem = nvmem_register(&econfig);
> + if (IS_ERR(nvmem))
> + return PTR_ERR(nvmem);
> +
> + platform_set_drvdata(pdev, nvmem);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id secumod_of_match[] = {
> + { .compatible = "atmel,sama5d2-secumod",},
> + {/* sentinel */},
> +};
> +MODULE_DEVICE_TABLE(of, secumod_of_match);
> +
> +static struct platform_driver secumod_driver = {
> + .probe = secumod_probe,
> + .remove = secumod_remove,
> + .driver = {
> + .name = "atmel,sama5d2-secumod",
> + .of_match_table = secumod_of_match,
> + },
> +};
> +module_platform_driver(secumod_driver);
> +MODULE_AUTHOR("David Mosberger <davidm@egauge.net>");
> +MODULE_DESCRIPTION("Atmel Secumod driver");
> +MODULE_LICENSE("GPL v2");
>