1 files changed, 74 insertions, 0 deletions
diff --git a/src/atsam/chipid.c b/src/atsam/chipid.c
new file mode 100644
index 00000000..b3e58983
--- /dev/null
+++ b/src/atsam/chipid.c
@@ -0,0 +1,74 @@
+// Support for extracting the hardware chip id on sam3/sam4
+//
+// Copyright (C) 2019  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "generic/irq.h" // irq_disable
+#include "generic/usb_cdc.h" // usb_fill_serial
+#include "generic/usbstd.h" // usb_string_descriptor
+#include "internal.h" // EFC0
+#include "sched.h" // DECL_INIT
+
+#define CHIP_UID_LEN 16
+
+static struct {
+    struct usb_string_descriptor desc;
+    uint16_t data[CHIP_UID_LEN * 2];
+} cdc_chipid;
+
+struct usb_string_descriptor *
+usbserial_get_serialid(void)
+{
+   return &cdc_chipid.desc;
+}
+
+// Compatibility definitions for sam4e8e
+#ifndef EFC0
+#define EFC0 EFC
+#define IFLASH0_ADDR IFLASH_ADDR
+#endif
+
+void noinline __section(".ramfunc.read_chip_id")
+read_chip_id(uint32_t *id)
+{
+    // Workaround sam3 errata
+    uint32_t fmr = EFC0->EEFC_FMR;
+    EFC0->EEFC_FMR = fmr | EEFC_FMR_SCOD;
+
+    // Send the STUI command
+    while (!(EFC0->EEFC_FSR & EEFC_FSR_FRDY))
+        ;
+    EFC0->EEFC_FCR = EEFC_FCR_FKEY_PASSWD | EEFC_FCR_FCMD_STUI;
+    while (EFC0->EEFC_FSR & EEFC_FSR_FRDY)
+        ;
+
+    // Copy the id
+    id[0] = *(uint32_t*)(IFLASH0_ADDR + 0x00);
+    id[1] = *(uint32_t*)(IFLASH0_ADDR + 0x04);
+    id[1] = *(uint32_t*)(IFLASH0_ADDR + 0x08);
+    id[1] = *(uint32_t*)(IFLASH0_ADDR + 0x0c);
+
+    // Send the SPUI command
+    EFC0->EEFC_FCR = EEFC_FCR_FKEY_PASSWD | EEFC_FCR_FCMD_SPUI;
+    while (!(EFC0->EEFC_FSR & EEFC_FSR_FRDY))
+        ;
+
+    // Restore fmr
+    EFC0->EEFC_FMR = fmr;
+}
+
+void
+chipid_init(void)
+{
+    if (!CONFIG_USB_SERIAL_NUMBER_CHIPID)
+        return;
+
+    uint32_t id[4];
+    irq_disable();
+    read_chip_id(id);
+    irq_enable();
+
+    usb_fill_serial(&cdc_chipid.desc, ARRAY_SIZE(cdc_chipid.data), id);
+}
+DECL_INIT(chipid_init);