read STM32 unique device identifier

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to OpenEMC will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 0.6.2 - 2023-04-08
+### Added
+- read unique device identifier
+
 ## 0.6.1 - 2023-03-07
 ### Fixed
 - system not powering on after watchdog reset

openemc-driver/openemc.c

@@ -362,6 +362,28 @@ int openemc_read_u64(struct openemc *emc, u8 command, u64 *value)
 }
 EXPORT_SYMBOL_GPL(openemc_read_u64);
 
+int openemc_read_u128(struct openemc *emc, u8 command, u64 *value_lo,
+		      u64 *value_hi)
+{
+	u8 buf[16];
+	int ret;
+
+	ret = openemc_request(emc, REQ_READ, command, ARRAY_SIZE(buf), buf);
+	if (ret < 0)
+		return ret;
+
+	*value_lo = (u64)buf[0] | (u64)buf[1] << 8 | (u64)buf[2] << 16 |
+		    (u64)buf[3] << 24 | (u64)buf[4] << 32 | (u64)buf[5] << 40 |
+		    (u64)buf[6] << 48 | (u64)buf[7] << 56;
+	*value_hi = (u64)buf[8] | (u64)buf[9] << 8 | (u64)buf[10] << 16 |
+		    (u64)buf[11] << 24 | (u64)buf[12] << 32 |
+		    (u64)buf[13] << 40 | (u64)buf[14] << 48 |
+		    (u64)buf[15] << 56;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(openemc_read_u128);
+
 int openemc_write_u64(struct openemc *emc, u8 command, u64 value)
 {
 	u8 buf[8];
@@ -1290,6 +1312,15 @@ static ssize_t openemc_board_model_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(openemc_board_model);
 
+static ssize_t openemc_unique_id_show(struct device *dev,
+				      struct device_attribute *attr, char *buf)
+{
+	struct openemc *emc = dev_get_drvdata(dev);
+	return sprintf(buf, "%08llx%016llx", emc->unique_id[1],
+		       emc->unique_id[0]);
+}
+static DEVICE_ATTR_RO(openemc_unique_id);
+
 static ssize_t openemc_boot_reason_show(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
@@ -1466,6 +1497,7 @@ static struct attribute *openemc_attrs[] = {
 	&dev_attr_openemc_flashable.attr,
 	&dev_attr_openemc_emc_model.attr,
 	&dev_attr_openemc_board_model.attr,
+	&dev_attr_openemc_unique_id.attr,
 	&dev_attr_openemc_boot_reason.attr,
 	&dev_attr_openemc_reset_status.attr,
 	&dev_attr_openemc_start_reason.attr,
@@ -1565,6 +1597,11 @@ static int openemc_get_info(struct openemc *emc)
 	if (ret < 0)
 		return ret;
 
+	ret = openemc_read_u128(emc, OPENEMC_UNIQUE_ID, &emc->unique_id[0],
+				&emc->unique_id[1]);
+	if (ret < 0)
+		return ret;
+
 	ret = openemc_read_u16(emc, OPENEMC_BOOT_REASON, &emc->boot_reason);
 	if (ret < 0)
 		return ret;
@@ -1696,7 +1733,11 @@ static int openemc_i2c_probe(struct i2c_client *i2c)
 	return 0;
 }
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0)
+static void openemc_i2c_remove(struct i2c_client *i2c)
+#else
 static int openemc_i2c_remove(struct i2c_client *i2c)
+#endif
 {
 	struct openemc *emc = i2c_get_clientdata(i2c);
 
@@ -1705,7 +1746,9 @@ static int openemc_i2c_remove(struct i2c_client *i2c)
 		irq_domain_remove(emc->irq_domain);
 	}
 
+#if !(LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0))
 	return 0;
+#endif
 }
 
 static struct i2c_driver openemc_i2c_driver = {

openemc-driver/openemc.h

@@ -25,6 +25,7 @@
 #define OPENEMC_EMC_MODEL 0x02
 #define OPENEMC_BOARD_MODEL 0x03
 #define OPENEMC_BOOTLOADER_VERSION 0x04
+#define OPENEMC_UNIQUE_ID 0x05
 #define OPENEMC_COPYRIGHT 0x06
 #define OPENEMC_MFD_CELL 0x07
 #define OPENEMC_BOOT_REASON 0x08
@@ -224,6 +225,7 @@ struct openemc {
 	char copyright[8 * OPENEMC_MAX_DATA_SIZE];
 	u8 emc_model;
 	char board_model[OPENEMC_MAX_DATA_SIZE + 1];
+	u64 unique_id[2];
 	u16 boot_reason;
 	u8 reset_status;
 	u8 start_reason;
@@ -261,6 +263,8 @@ int openemc_read_u32(struct openemc *emc, u8 command, u32 *value);
 int openemc_write_u32(struct openemc *emc, u8 command, u32 value);
 int openemc_read_u64(struct openemc *emc, u8 command, u64 *value);
 int openemc_write_u64(struct openemc *emc, u8 command, u64 value);
+int openemc_read_u128(struct openemc *emc, u8 command, u64 *value_lo,
+		      u64 *value_hi);
 int openemc_read_data(struct openemc *emc, u8 command, u8 len, u8 *data);
 int openemc_write_data(struct openemc *emc, u8 command, u8 len, const u8 *data);
 

openemc-firmware/Cargo.toml

@@ -3,7 +3,7 @@ name = "openemc-firmware"
 description = "OpenEMC Firmware"
 authors = ["Sebastian Urban <[email protected]>"]
 license = "GPL-3.0"
-version = "0.6.1"
+version = "0.6.2"
 publish = false
 edition = "2021"
 

openemc-firmware/src/i2c_reg_slave.rs

@@ -326,4 +326,26 @@ impl<const BUFFER: usize> Response<BUFFER> {
             ((value >> 56) & 0xff) as u8,
         ])
     }
+
+    /// Sets the register value to an u128 with LSB first.
+    pub fn set_u128(value: u128) -> Self {
+        Self::set(&[
+            (value & 0xff) as u8,
+            ((value >> 8) & 0xff) as u8,
+            ((value >> 16) & 0xff) as u8,
+            ((value >> 24) & 0xff) as u8,
+            ((value >> 32) & 0xff) as u8,
+            ((value >> 40) & 0xff) as u8,
+            ((value >> 48) & 0xff) as u8,
+            ((value >> 56) & 0xff) as u8,
+            ((value >> 64) & 0xff) as u8,
+            ((value >> 72) & 0xff) as u8,
+            ((value >> 80) & 0xff) as u8,
+            ((value >> 88) & 0xff) as u8,
+            ((value >> 96) & 0xff) as u8,
+            ((value >> 104) & 0xff) as u8,
+            ((value >> 112) & 0xff) as u8,
+            ((value >> 120) & 0xff) as u8,
+        ])
+    }
 }

openemc-firmware/src/main.rs

@@ -82,7 +82,7 @@ use crate::{
     pwm::PwmTimer,
     rtc::{ClockSrc, Rtc},
     supply::{max14636::Max14636, stusb4500::StUsb4500, PowerSupply},
-    util::{array_from_u16, array_from_u64, array_to_u16, array_to_u64},
+    util::{array_from_u16, array_from_u64, array_to_u16, array_to_u64, unique_device_id},
     watchman::Watchman,
 };
 use openemc_shared::{BootInfo, BootReason};
@@ -338,6 +338,7 @@ mod app {
         }
         defmt::info!("EMC model:      0x{:02x}", bi.emc_model);
         defmt::info!("board model:    {:a}", bi.board_model());
+        defmt::info!("unique id:      {:024x}", unique_device_id());
         defmt::info!("I2C address:    0x{:02x} (pins remapped: {:?})", ThisBoard::I2C_ADDR, ThisBoard::I2C_REMAP);
         defmt::info!("IRQ pin:        {} (mode: 0b{:04b})", ThisBoard::IRQ_PIN, ThisBoard::IRQ_PIN_CFG);
         BootReason::log(bi.boot_reason);
@@ -1110,6 +1111,7 @@ mod app {
         let respond_u16 = |response: u16| respond(Response::set_u16(response));
         let respond_u32 = |response: u32| respond(Response::set_u32(response));
         let respond_u64 = |response: u64| respond(Response::set_u64(response));
+        let respond_u128 = |response: u128| respond(Response::set_u128(response));
 
         match evt {
             Event::Read { reg: reg::ID } => {
@@ -1122,6 +1124,7 @@ mod app {
                 Some(v) => respond_slice(v),
                 None => respond_slice(&[0]),
             },
+            Event::Read { reg: reg::UNIQUE_ID } => respond_u128(unique_device_id()),
             Event::Read { reg: reg::COPYRIGHT } => {
                 respond_clipped(COPYRIGHT.get(*cx.local.copyright_offset..).unwrap_or_default())
             }

openemc-firmware/src/reg.rs

@@ -15,6 +15,9 @@ pub const BOARD_MODEL: u8 = 0x03;
 /// Read bootloader version (string).
 pub const BOOTLOADER_VERSION: u8 = 0x04;
 
+/// Read 96-bit unique device identifier (u128).
+pub const UNIQUE_ID: u8 = 0x05;
+
 /// Copyright.
 /// Read: string starting at offset.
 /// Write u8: set offset.

openemc-firmware/src/util.rs

@@ -1,6 +1,6 @@
 //! Debug functions.
 
-use core::mem::size_of;
+use core::{mem::size_of, ptr};
 use defmt::unwrap;
 
 // use crate::CPU_CLOCK;
@@ -66,3 +66,15 @@ pub fn array_to_u16<const D: usize>(flat: &[u8]) -> [u16; D] {
     }
     data
 }
+
+/// 96-bit unique device identifier.
+pub fn unique_device_id() -> u128 {
+    const BASE: usize = 0x1FFFF7E8;
+    unsafe {
+        let a = ptr::read_unaligned(BASE as *const u16) as u128;
+        let b = ptr::read_unaligned((BASE + 2) as *const u16) as u128;
+        let c = ptr::read_unaligned((BASE + 4) as *const u32) as u128;
+        let d = ptr::read_unaligned((BASE + 8) as *const u32) as u128;
+        a | (b << 16) | (c << 32) | (d << 64)
+    }
+}