Add support for board version reading via ADC

firmware/Makefile

@@ -145,7 +145,7 @@ VPATH += src_board src_sam3s cmsis $(USB_PATHS) src_simtrace src_libosmocore
 # Objects built from C source files
 C_CMSIS    = core_cm3.o
 C_LOWLEVEL = board_cstartup_gnu.o board_lowlevel.o syscalls.o exceptions.o
-C_LIBLEVEL = spi.o pio.o pmc.o usart.o pio_it.o pio_capture.o uart_console.o iso7816_4.o wdt.o led.o tc.o unique_id.o
+C_LIBLEVEL = spi.o pio.o pmc.o usart.o pio_it.o pio_capture.o uart_console.o iso7816_4.o wdt.o led.o tc.o unique_id.o boardver_adc.o
 C_CCID = cciddriver.o USBD.o USBDDriver.o USBD_HAL.o USBRequests.o USBDCallbacks.o USBDescriptors.o USBDDriverCallbacks.o
 C_SIMTRACE = simtrace_iso7816.o usb.o ccid.o sniffer.o mitm.o ringbuffer.o host_communication.o iso7816_fidi.o tc_etu.o req_ctx.o card_emu.o mode_cardemu.o i2c.o wwan_led.o wwan_perst.o
 C_OSMOCORE = timer.o rbtree.o

firmware/include_board/boardver_adc.h

@@ -0,0 +1,3 @@
+#pragma once
+
+int get_board_version_adc(void);

firmware/include_board/qmod/board.h

@@ -53,6 +53,8 @@
 #define PIN_PERST2		{PIO_PA26, PIOA, ID_PIOA, PIO_OUTPUT_1, PIO_PULLUP}
 #define PINS_PERST		{ PIN_PERST1, PIN_PERST2 }
 
+#define PIN_VERSION_DET		{PIO_PA19, PIOA, ID_PIOA, PIO_PERIPH_D, PIO_DEFAULT}
+
 #define SIMTRACE_VENDOR_ID          0x1d50
 #define SIMTRACE_PRODUCT_ID         0x60e3	/* FIXME */
 #define USB_VENDOR_ID               SIMTRACE_VENDOR_ID

firmware/src_board/boardver_adc.c

@@ -0,0 +1,83 @@
+#include "board.h"
+#include "boardver_adc.h"
+
+/* FIXME: share this with mode_cardemu.c */
+#define UV_PER_LSB	((3300 * 1000) / 4096)
+static uint32_t adc2uv(uint16_t adc)
+{
+	uint32_t uv = (uint32_t) adc * UV_PER_LSB;
+	return uv;
+}
+
+/***********************************************************************
+ * ADC for board version detection
+ ***********************************************************************/
+
+#ifdef PIN_VERSION_DET
+
+static int adc_sam3s_reva_errata = 0;
+
+static const Pin pin_version_det = PIN_VERSION_DET;
+
+/* Warning: Don't call this while other code (like the SIM VCC voltage
+ * reading) is running.  The idea is you call this once during board
+ * startup and cache the result in a (global) variable if you need it
+ * later throughout the code */
+int get_board_version_adc(void)
+{
+	uint32_t chip_arch = CHIPID->CHIPID_CIDR & CHIPID_CIDR_ARCH_Msk;
+	uint32_t chip_ver = CHIPID->CHIPID_CIDR & CHIPID_CIDR_VERSION_Msk;
+	uint16_t sample;
+	uint32_t uv;
+
+	PIO_Configure(&pin_version_det, 1);
+
+	PMC_EnablePeripheral(ID_ADC);
+
+	ADC->ADC_CR |= ADC_CR_SWRST;
+	if (chip_ver == 0 &&
+	    (chip_arch == CHIPID_CIDR_ARCH_SAM3SxA ||
+	     chip_arch == CHIPID_CIDR_ARCH_SAM3SxB ||
+	     chip_arch == CHIPID_CIDR_ARCH_SAM3SxC)) {
+		TRACE_INFO("Enabling Rev.A ADC Errata work-around\r\n");
+		adc_sam3s_reva_errata = 1;
+	}
+
+	if (adc_sam3s_reva_errata) {
+		/* Errata Work-Around to clear EOCx flags */
+		volatile uint32_t foo;
+		int i;
+		for (i = 0; i < 16; i++)
+			foo = ADC->ADC_CDR[i];
+	}
+
+	/* Initialize ADC for AD2, fADC=48/24=2MHz */
+	ADC->ADC_MR = ADC_MR_TRGEN_DIS | ADC_MR_LOWRES_BITS_12 |
+		      ADC_MR_SLEEP_NORMAL | ADC_MR_FWUP_OFF |
+		      ADC_MR_FREERUN_OFF | ADC_MR_PRESCAL(23) |
+		      ADC_MR_STARTUP_SUT8 | ADC_MR_SETTLING(3) |
+		      ADC_MR_ANACH_NONE | ADC_MR_TRACKTIM(4) |
+		      ADC_MR_TRANSFER(1) | ADC_MR_USEQ_NUM_ORDER;
+	/* enable AD2 channel only */
+	ADC->ADC_CHER = ADC_CHER_CH2;
+
+	/* Make sure we don't use interrupts as that's what the SIM card
+	 * VCC ADC code is using */
+	ADC->ADC_IER = 0;
+	NVIC_DisableIRQ(ADC_IRQn);
+
+	ADC->ADC_CR |= ADC_CR_START;
+
+	/* busy-wait, actually read the value */
+	do { } while (!(ADC->ADC_ISR & ADC_ISR_EOC2));
+	/* convert to voltage */
+	sample = ADC->ADC_CDR[2];
+	uv = adc2uv(sample);
+	TRACE_INFO("VERSION_DET ADC=%u => %u uV\r\n", sample, uv);
+
+	/* FIXME: convert to board version based on thresholds */
+
+	return 0;
+}
+
+#endif /* PIN_VERSION_DET */

firmware/src_simtrace/main.c

@@ -9,6 +9,7 @@
 #include "req_ctx.h"
 #include "wwan_led.h"
 #include "wwan_perst.h"
+#include "boardver_adc.h"
 #include "osmocom/core/timer.h"
 
 uint32_t g_unique_id[4];
@@ -320,6 +321,9 @@ extern int main(void)
 		TRACE_INFO("Detected Quad-Modem ST34\r\n");
 	}
 
+	/* Obtain the circuit board version (currently just prints voltage */
+	get_board_version_adc();
+
 	TRACE_INFO("USB init...\r\n");
 	SIMtrace_USB_Initialize();