lpc176x: read chip id and use as usb serial. (#2184)

Signed-off-by: Matt Baker <baker.matt.j@gmail.com>

src/Kconfig

@@ -50,6 +50,10 @@ config SERIAL_BAUD
         Specify the baud rate of the serial port. This should be set
         to 250000. Read the FAQ before changing this value.
 
+config HAVE_CHIPID
+    bool
+    default n
+
 # Generic configuration options for USB
 menu "USB ids"
     depends on USBSERIAL
@@ -61,8 +65,12 @@ config USB_DEVICE_ID
     hex "USB device ID"
     default 0xabcd
 config USB_SERIAL_NUMBER
-    string "USB serial number"
+    string "USB serial number" if !USB_SERIAL_NUMBER_CHIPID
     default "12345"
+config USB_SERIAL_NUMBER_CHIPID
+    depends on HAVE_CHIPID
+    bool "USB serial number from CHIPID"
+    default y
 
 endmenu
 

src/generic/usb_cdc.c

@@ -358,21 +358,34 @@ usb_req_get_descriptor(struct usb_ctrlrequest *req)
 {
     if (req->bRequestType != USB_DIR_IN)
         goto fail;
-    uint_fast8_t i;
+    void *desc = NULL;
+    uint_fast8_t flags, size, i;
     for (i=0; i<ARRAY_SIZE(cdc_descriptors); i++) {
         const struct descriptor_s *d = &cdc_descriptors[i];
         if (READP(d->wValue) == req->wValue
             && READP(d->wIndex) == req->wIndex) {
-            uint_fast8_t size = READP(d->size);
-            uint_fast8_t flags = NEED_PROGMEM ? UX_SEND_PROGMEM : UX_SEND;
-            if (size > req->wLength)
-                size = req->wLength;
-            else if (size < req->wLength)
-                flags |= UX_SEND_ZLP;
-            usb_do_xfer((void*)READP(d->desc), size, flags);
-            return;
+            flags = NEED_PROGMEM ? UX_SEND_PROGMEM : UX_SEND;
+            size = READP(d->size);
+            desc = (void*)READP(d->desc);
         }
     }
+    if (CONFIG_USB_SERIAL_NUMBER_CHIPID
+        && req->wValue == ((USB_DT_STRING<<8) | USB_STR_ID_SERIAL)
+        && req->wIndex == USB_LANGID_ENGLISH_US) {
+            struct usb_string_descriptor *usbserial_serialid;
+            usbserial_serialid = usbserial_get_serialid();
+            flags = UX_SEND;
+            size = usbserial_serialid->bLength;
+            desc = (void*)usbserial_serialid;
+    }
+    if (desc) {
+        if (size > req->wLength)
+            size = req->wLength;
+        else if (size < req->wLength)
+            flags |= UX_SEND_ZLP;
+        usb_do_xfer(desc, size, flags);
+        return;
+    }
 fail:
     usb_do_stall();
 }

src/generic/usb_cdc.h

@@ -22,6 +22,7 @@ void usb_stall_ep0(void);
 void usb_set_address(uint_fast8_t addr);
 void usb_set_configure(void);
 void usb_request_bootloader(void);
+struct usb_string_descriptor *usbserial_get_serialid(void);
 
 // usb_cdc.c
 void usb_notify_bulk_in(void);

src/lpc176x/Kconfig

@@ -66,4 +66,8 @@ config SERIAL
     bool
     default y
 
+config HAVE_CHIPID
+    bool
+    default y
+
 endif

src/lpc176x/usbserial.c

@@ -13,6 +13,7 @@
 #include "byteorder.h" // cpu_to_le32
 #include "command.h" // DECL_CONSTANT_STR
 #include "generic/usb_cdc.h" // usb_notify_ep0
+#include "generic/usbstd.h" // usb_string_descriptor
 #include "internal.h" // gpio_peripheral
 #include "sched.h" // DECL_INIT
 #include "usb_cdc_ep.h" // USB_CDC_EP_BULK_IN
@@ -34,6 +35,12 @@
 #define RD_EN (1<<0)
 #define WR_EN (1<<1)
 
+// IAP interface
+#define IAP_LOCATION        0x1fff1ff1
+#define IAP_CMD_READ_UID    58
+#define IAP_UID_LEN         16
+typedef void (*IAP)(uint32_t *, uint32_t *);
+
 static void
 usb_irq_disable(void)
 {
@@ -104,6 +111,16 @@ sie_select_and_clear(uint32_t idx)
 /****************************************************************
  * Interface
  ****************************************************************/
+#define USB_STR_SERIAL_CHIPID u"0123456789ABCDEF0123456789ABCDEF"
+
+#define SIZE_cdc_string_serial_chipid \
+    (sizeof(cdc_string_serial_chipid) + sizeof(USB_STR_SERIAL_CHIPID) - 2)
+
+static struct usb_string_descriptor cdc_string_serial_chipid = {
+    .bLength = SIZE_cdc_string_serial_chipid,
+    .bDescriptorType = USB_DT_STRING,
+    .data = USB_STR_SERIAL_CHIPID,
+};
 
 static int_fast8_t
 usb_write_packet(uint32_t ep, const void *data, uint_fast8_t len)
@@ -260,10 +277,36 @@ usb_request_bootloader(void)
     NVIC_SystemReset();
 }
 
+struct usb_string_descriptor *
+usbserial_get_serialid(void)
+{
+   return &cdc_string_serial_chipid;
+}
 
 /****************************************************************
  * Setup and interrupts
  ****************************************************************/
+static void
+usb_set_serial(void)
+{
+    uint32_t iap_cmd_uid[5] = {IAP_CMD_READ_UID, 0, 0, 0, 0};
+    uint32_t iap_resp[5];
+
+    IAP iap_entry = (IAP)IAP_LOCATION;
+    __disable_irq();
+    iap_entry(iap_cmd_uid, iap_resp);
+    __enable_irq();
+
+    uint8_t *chipid = (uint8_t *)&iap_resp[1];
+    uint8_t i, j, c;
+    for (i = 0; i < IAP_UID_LEN; i++) {
+        for (j = 0; j < 2; j++) {
+            c = (chipid[i] >> 4*j) & 0xF;
+            c = (c < 10) ? '0'+c : 'A'-10+c;
+            cdc_string_serial_chipid.data[2*i+((j)?0:1)] = c;
+        }
+    }
+}
 
 void
 USB_IRQHandler(void)
@@ -300,6 +343,9 @@ DECL_CONSTANT_STR("RESERVE_PINS_USB", "P0.30,P0.29,P2.9");
 void
 usbserial_init(void)
 {
+    if (CONFIG_USB_SERIAL_NUMBER_CHIPID)
+        usb_set_serial();
+
     usb_irq_disable();
     // enable power
     enable_pclock(PCLK_USB);