The Amlogic Meson SoC Secure Monitor implements a call to retrieve an
unique CHIP ID with CPU ID (128 bits length) starting from the GX
Family and all new families.

The chipid string is simply exposed as a sysfs entry under the firmware
sysfs directory.

Signed-off-by: Viacheslav Bocharov <adeep@lexina.in>
---
 drivers/firmware/meson/meson_sm.c | 54 ++++++++++++++++++++++++++++++-
 1 file changed, 53 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/meson/meson_sm.c b/drivers/firmware/meson/meson_sm.c
index c1c694b485ee..2820f4ac871b 100644
--- a/drivers/firmware/meson/meson_sm.c
+++ b/drivers/firmware/meson/meson_sm.c
@@ -240,9 +240,10 @@ struct meson_sm_firmware *meson_sm_get(struct device_node *sm_node)
 }
 EXPORT_SYMBOL_GPL(meson_sm_get);
 
-#define SM_CHIP_ID_LENGTH	119
+#define SM_CHIP_ID_LENGTH	128
 #define SM_CHIP_ID_OFFSET	4
 #define SM_CHIP_ID_SIZE		12
+#define SM_CHIP_IDv2_SIZE	16
 
 static ssize_t serial_show(struct device *dev, struct device_attribute *attr,
 			 char *buf)
@@ -274,8 +275,59 @@ static ssize_t serial_show(struct device *dev, struct device_attribute *attr,
 
 static DEVICE_ATTR_RO(serial);
 
+static ssize_t chipid_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct meson_sm_firmware *fw;
+	uint8_t *id_buf;
+	int ret;
+
+	fw = platform_get_drvdata(pdev);
+
+	id_buf = kmalloc(SM_CHIP_ID_LENGTH, GFP_KERNEL);
+	if (!id_buf)
+		return -ENOMEM;
+
+	ret = meson_sm_call_read(fw, id_buf, SM_CHIP_ID_LENGTH, SM_GET_CHIP_ID,
+				 2, 0, 0, 0, 0);
+	if (ret < 0) {
+		kfree(id_buf);
+		return ret;
+	}
+
+	int version = *((unsigned int *)id_buf);
+
+	if (version == 2)
+		ret = scnprintf(buf, PAGE_SIZE, "%16phN\n", &id_buf[SM_CHIP_ID_OFFSET]);
+	else {
+		/**
+		 * Legacy 12-byte chip ID read out, transform data
+		 * to expected order format.
+		 */
+		uint8_t *buff;
+
+		buff = kmalloc(SM_CHIP_ID_LENGTH, GFP_KERNEL);
+		if (!buff)
+			return -ENOMEM;
+		((uint32_t *)buff)[0] = 0; // CPU_ID is empty
+		/* Transform into expected order for display */
+		ch = (uint8_t *)(id_buf + 4);
+		for (i = 0; i < 12; i++)
+			buff[i + 4] = ch[11 - i];
+		ret = scnprintf(buf, PAGE_SIZE, "%16phN\n", &buff);
+		kfree(buff);
+	}
+
+	kfree(id_buf);
+	return ret;
+}
+
+static DEVICE_ATTR_RO(chipid);
+
 static struct attribute *meson_sm_sysfs_attributes[] = {
 	&dev_attr_serial.attr,
+	&dev_attr_chipid.attr,
 	NULL,
 };
 
-- 
2.34.1

Hi Viacheslav,

kernel test robot noticed the following build errors:

[auto build test ERROR on soc/for-next]
[also build test ERROR on linus/master v6.6 next-20231102]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Viacheslav-Bocharov/firmware-meson-sm-change-sprintf-to-scnprintf/20231102-172556
base:   https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
patch link:    https://lore.kernel.org/r/20231102074916.3280809-3-adeep%40lexina.in
patch subject: [PATCH 2/4] firmware: meson_sm: Add chipid number sysfs entry
config: arm64-randconfig-003-20231103 (https://download.01.org/0day-ci/archive/20231103/202311030513.HxyDUCuc-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231103/202311030513.HxyDUCuc-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311030513.HxyDUCuc-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/firmware/meson/meson_sm.c: In function 'chipid_show':
>> drivers/firmware/meson/meson_sm.c:315:17: error: 'ch' undeclared (first use in this function)
     315 |                 ch = (uint8_t *)(id_buf + 4);
         |                 ^~
   drivers/firmware/meson/meson_sm.c:315:17: note: each undeclared identifier is reported only once for each function it appears in
>> drivers/firmware/meson/meson_sm.c:316:22: error: 'i' undeclared (first use in this function)
     316 |                 for (i = 0; i < 12; i++)
         |                      ^


vim +/ch +315 drivers/firmware/meson/meson_sm.c

   277	
   278	static ssize_t chipid_show(struct device *dev, struct device_attribute *attr,
   279				 char *buf)
   280	{
   281		struct platform_device *pdev = to_platform_device(dev);
   282		struct meson_sm_firmware *fw;
   283		uint8_t *id_buf;
   284		int ret;
   285	
   286		fw = platform_get_drvdata(pdev);
   287	
   288		id_buf = kmalloc(SM_CHIP_ID_LENGTH, GFP_KERNEL);
   289		if (!id_buf)
   290			return -ENOMEM;
   291	
   292		ret = meson_sm_call_read(fw, id_buf, SM_CHIP_ID_LENGTH, SM_GET_CHIP_ID,
   293					 2, 0, 0, 0, 0);
   294		if (ret < 0) {
   295			kfree(id_buf);
   296			return ret;
   297		}
   298	
   299		int version = *((unsigned int *)id_buf);
   300	
   301		if (version == 2)
   302			ret = scnprintf(buf, PAGE_SIZE, "%16phN\n", &id_buf[SM_CHIP_ID_OFFSET]);
   303		else {
   304			/**
   305			 * Legacy 12-byte chip ID read out, transform data
   306			 * to expected order format.
   307			 */
   308			uint8_t *buff;
   309	
   310			buff = kmalloc(SM_CHIP_ID_LENGTH, GFP_KERNEL);
   311			if (!buff)
   312				return -ENOMEM;
   313			((uint32_t *)buff)[0] = 0; // CPU_ID is empty
   314			/* Transform into expected order for display */
 > 315			ch = (uint8_t *)(id_buf + 4);
 > 316			for (i = 0; i < 12; i++)
   317				buff[i + 4] = ch[11 - i];
   318			ret = scnprintf(buf, PAGE_SIZE, "%16phN\n", &buff);
   319			kfree(buff);
   320		}
   321	
   322		kfree(id_buf);
   323		return ret;
   324	}
   325	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki