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Message-Id: <1532613556-5398-1-git-send-email-narmstrong@baylibre.com>
Date: Thu, 26 Jul 2018 15:59:16 +0200
From: Neil Armstrong <narmstrong@...libre.com>
To: khilman@...libre.com, carlo@...one.org
Cc: Neil Armstrong <narmstrong@...libre.com>,
linux-amlogic@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] firmware: meson_sm: Add serial number sysfs entry
The Amlogic Meson SoC Secure Monitor implements a call to retrieve an unique
SoC ID starting from the GX Family and all new families.
The serial number is simply exposed as a sysfs entry under the firmware
sysfs directory.
Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
---
drivers/firmware/meson/meson_sm.c | 56 +++++++++++++++++++++++++++++++++
include/linux/firmware/meson/meson_sm.h | 1 +
2 files changed, 57 insertions(+)
diff --git a/drivers/firmware/meson/meson_sm.c b/drivers/firmware/meson/meson_sm.c
index 0ec2ca8..29fbc81 100644
--- a/drivers/firmware/meson/meson_sm.c
+++ b/drivers/firmware/meson/meson_sm.c
@@ -24,6 +24,7 @@
#include <linux/printk.h>
#include <linux/types.h>
#include <linux/sizes.h>
+ #include <linux/slab.h>
#include <linux/firmware/meson/meson_sm.h>
@@ -48,6 +49,7 @@ struct meson_sm_chip gxbb_chip = {
CMD(SM_EFUSE_READ, 0x82000030),
CMD(SM_EFUSE_WRITE, 0x82000031),
CMD(SM_EFUSE_USER_MAX, 0x82000033),
+ CMD(SM_GET_CHIP_ID, 0x82000044),
{ /* sentinel */ },
},
};
@@ -214,6 +216,57 @@ int meson_sm_call_write(void *buffer, unsigned int size, unsigned int cmd_index,
}
EXPORT_SYMBOL(meson_sm_call_write);
+#define SM_CHIP_ID_LENGTH 119
+#define SM_CHIP_ID_OFFSET 4
+#define SM_CHIP_ID_SIZE 12
+
+static ssize_t serial_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ uint8_t *id_buf;
+ int ret;
+
+ id_buf = kmalloc(SM_CHIP_ID_LENGTH, GFP_KERNEL);
+ if (!id_buf)
+ return -ENOMEM;
+
+ ret = meson_sm_call_read(id_buf, SM_CHIP_ID_LENGTH, SM_GET_CHIP_ID,
+ 0, 0, 0, 0, 0);
+ if (ret < 0) {
+ kfree(id_buf);
+ return ret;
+ }
+
+ ret = sprintf(buf, "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n",
+ id_buf[SM_CHIP_ID_OFFSET + 0],
+ id_buf[SM_CHIP_ID_OFFSET + 1],
+ id_buf[SM_CHIP_ID_OFFSET + 2],
+ id_buf[SM_CHIP_ID_OFFSET + 3],
+ id_buf[SM_CHIP_ID_OFFSET + 4],
+ id_buf[SM_CHIP_ID_OFFSET + 5],
+ id_buf[SM_CHIP_ID_OFFSET + 6],
+ id_buf[SM_CHIP_ID_OFFSET + 7],
+ id_buf[SM_CHIP_ID_OFFSET + 8],
+ id_buf[SM_CHIP_ID_OFFSET + 9],
+ id_buf[SM_CHIP_ID_OFFSET + 10],
+ id_buf[SM_CHIP_ID_OFFSET + 11]);
+
+ kfree(id_buf);
+
+ return ret;
+}
+
+static DEVICE_ATTR_RO(serial);
+
+static struct attribute *meson_sm_sysfs_attributes[] = {
+ &dev_attr_serial.attr,
+ NULL,
+};
+
+static const struct attribute_group meson_sm_sysfs_attr_group = {
+ .attrs = meson_sm_sysfs_attributes,
+};
+
static const struct of_device_id meson_sm_ids[] = {
{ .compatible = "amlogic,meson-gxbb-sm", .data = &gxbb_chip },
{ /* sentinel */ },
@@ -242,6 +295,9 @@ static int __init meson_sm_probe(struct platform_device *pdev)
fw.chip = chip;
pr_info("secure-monitor enabled\n");
+ if (sysfs_create_group(&pdev->dev.kobj, &meson_sm_sysfs_attr_group))
+ goto out_in_base;
+
return 0;
out_in_base:
diff --git a/include/linux/firmware/meson/meson_sm.h b/include/linux/firmware/meson/meson_sm.h
index 37a5eae..f98c20d 100644
--- a/include/linux/firmware/meson/meson_sm.h
+++ b/include/linux/firmware/meson/meson_sm.h
@@ -17,6 +17,7 @@ enum {
SM_EFUSE_READ,
SM_EFUSE_WRITE,
SM_EFUSE_USER_MAX,
+ SM_GET_CHIP_ID,
};
struct meson_sm_firmware;
--
2.7.4
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