* [PATCH v6] soc: at91: Add Atmel SFR SN (Serial Number) support
@ 2019-10-04 15:18 Kamel Bouhara
2019-10-05 19:57 ` Alexandre Belloni
0 siblings, 1 reply; 2+ messages in thread
From: Kamel Bouhara @ 2019-10-04 15:18 UTC (permalink / raw)
To: Nicolas Ferre, Alexandre Belloni, Ludovic Desroches, linux-arm-kernel
Cc: Kamel Bouhara, Thomas Petazzoni, Tudor Ambarus
Add support to read SFR's read-only registers providing the SoC
Serial Numbers (SN0+SN1) to userspace.
~ # hexdump -n 8 -e'"%d\n"' /sys/bus/nvmem/devices/atmel-sfr0/nvmem
959527243
371539274
Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Tested-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
Changes in v2:
- updated atmel-sfr.c to sfr.c in Makefile
- fixed missing drvdata struct definition
- added missing syscon header
Changes in v3:
- Fixed typo: processor in Kconfig
- Renamed private struct sfr_priv to atmel_sfr_priv
- Dropped the drvdata structure as we have same size for both SN
registers in SAMA5D2/4, just hardcoded it for now.
- Cleaned up private struct from unused members
- Fixed misusage of devm_kzalloc
Changes in v5:
- Removed the blankline at EOF
- Feeded the entropy pool with the SoC SN using add_device_randomness()
and do it only once at probe().
Changes in v6:
- Fixed missing return of a possible error from atmel_sfr_read()
- Added T-b and R-b tags
drivers/soc/atmel/Kconfig | 11 +++++
drivers/soc/atmel/Makefile | 1 +
drivers/soc/atmel/sfr.c | 99 ++++++++++++++++++++++++++++++++++++++
3 files changed, 111 insertions(+)
create mode 100644 drivers/soc/atmel/sfr.c
diff --git a/drivers/soc/atmel/Kconfig b/drivers/soc/atmel/Kconfig
index 05528139b023..50caf6db9c0e 100644
--- a/drivers/soc/atmel/Kconfig
+++ b/drivers/soc/atmel/Kconfig
@@ -5,3 +5,14 @@ config AT91_SOC_ID
default ARCH_AT91
help
Include support for the SoC bus on the Atmel ARM SoCs.
+
+config AT91_SOC_SFR
+ tristate "Special Function Registers support"
+ depends on ARCH_AT91 || COMPILE_TEST
+ help
+ This is a driver for the Special Function Registers available on
+ Atmel SAMA5Dx SoCs, providing access to specific aspects of the
+ integrated memory, bridge implementations, processor etc.
+
+ This driver can also be built as a module. If so, the module
+ will be called sfr.
diff --git a/drivers/soc/atmel/Makefile b/drivers/soc/atmel/Makefile
index 7ca355d10553..d849a897cd77 100644
--- a/drivers/soc/atmel/Makefile
+++ b/drivers/soc/atmel/Makefile
@@ -1,2 +1,3 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_AT91_SOC_ID) += soc.o
+obj-$(CONFIG_AT91_SOC_SFR) += sfr.o
diff --git a/drivers/soc/atmel/sfr.c b/drivers/soc/atmel/sfr.c
new file mode 100644
index 000000000000..0525eef49d1a
--- /dev/null
+++ b/drivers/soc/atmel/sfr.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sfr.c - driver for special function registers
+ *
+ * Copyright (C) 2019 Bootlin.
+ *
+ */
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/random.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define SFR_SN0 0x4c
+#define SFR_SN_SIZE 8
+
+struct atmel_sfr_priv {
+ struct regmap *regmap;
+};
+
+static int atmel_sfr_read(void *context, unsigned int offset,
+ void *buf, size_t bytes)
+{
+ struct atmel_sfr_priv *priv = context;
+
+ return regmap_bulk_read(priv->regmap, SFR_SN0 + offset,
+ buf, bytes / 4);
+}
+
+static struct nvmem_config atmel_sfr_nvmem_config = {
+ .name = "atmel-sfr",
+ .read_only = true,
+ .word_size = 4,
+ .stride = 4,
+ .size = SFR_SN_SIZE,
+ .reg_read = atmel_sfr_read,
+};
+
+static int atmel_sfr_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct nvmem_device *nvmem;
+ struct atmel_sfr_priv *priv;
+ u8 sn[SFR_SN_SIZE];
+ int ret;
+
+ priv = devm_kmalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->regmap = syscon_node_to_regmap(np);
+ if (IS_ERR(priv->regmap)) {
+ dev_err(dev, "cannot get parent's regmap\n");
+ return PTR_ERR(priv->regmap);
+ }
+
+ atmel_sfr_nvmem_config.dev = dev;
+ atmel_sfr_nvmem_config.priv = priv;
+
+ nvmem = devm_nvmem_register(dev, &atmel_sfr_nvmem_config);
+ if (IS_ERR(nvmem)) {
+ dev_err(dev, "error registering nvmem config\n");
+ return PTR_ERR(nvmem);
+ }
+
+ ret = atmel_sfr_read(priv, 0, sn, SFR_SN_SIZE);
+ if (ret == 0)
+ add_device_randomness(sn, SFR_SN_SIZE);
+
+ return ret;
+}
+
+static const struct of_device_id atmel_sfr_dt_ids[] = {
+ {
+ .compatible = "atmel,sama5d2-sfr",
+ }, {
+ .compatible = "atmel,sama5d4-sfr",
+ }, {
+ /* sentinel */
+ },
+};
+MODULE_DEVICE_TABLE(of, atmel_sfr_dt_ids);
+
+static struct platform_driver atmel_sfr_driver = {
+ .probe = atmel_sfr_probe,
+ .driver = {
+ .name = "atmel-sfr",
+ .of_match_table = atmel_sfr_dt_ids,
+ },
+};
+module_platform_driver(atmel_sfr_driver);
+
+MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
+MODULE_DESCRIPTION("Atmel SFR SN driver for SAMA5D2/4 SoC family");
+MODULE_LICENSE("GPL v2");
--
2.23.0
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v6] soc: at91: Add Atmel SFR SN (Serial Number) support
2019-10-04 15:18 [PATCH v6] soc: at91: Add Atmel SFR SN (Serial Number) support Kamel Bouhara
@ 2019-10-05 19:57 ` Alexandre Belloni
0 siblings, 0 replies; 2+ messages in thread
From: Alexandre Belloni @ 2019-10-05 19:57 UTC (permalink / raw)
To: Kamel Bouhara
Cc: Thomas Petazzoni, Ludovic Desroches, linux-arm-kernel, Tudor Ambarus
On 04/10/2019 17:18:02+0200, Kamel Bouhara wrote:
> Add support to read SFR's read-only registers providing the SoC
> Serial Numbers (SN0+SN1) to userspace.
>
> ~ # hexdump -n 8 -e'"%d\n"' /sys/bus/nvmem/devices/atmel-sfr0/nvmem
> 959527243
> 371539274
>
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Tested-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
> Changes in v2:
> - updated atmel-sfr.c to sfr.c in Makefile
> - fixed missing drvdata struct definition
> - added missing syscon header
> Changes in v3:
> - Fixed typo: processor in Kconfig
> - Renamed private struct sfr_priv to atmel_sfr_priv
> - Dropped the drvdata structure as we have same size for both SN
> registers in SAMA5D2/4, just hardcoded it for now.
> - Cleaned up private struct from unused members
> - Fixed misusage of devm_kzalloc
> Changes in v5:
> - Removed the blankline at EOF
> - Feeded the entropy pool with the SoC SN using add_device_randomness()
> and do it only once at probe().
> Changes in v6:
> - Fixed missing return of a possible error from atmel_sfr_read()
> - Added T-b and R-b tags
>
> drivers/soc/atmel/Kconfig | 11 +++++
> drivers/soc/atmel/Makefile | 1 +
> drivers/soc/atmel/sfr.c | 99 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 111 insertions(+)
> create mode 100644 drivers/soc/atmel/sfr.c
>
Applied, thanks.
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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