altos/usbtrng-v2.0: Use stmf042 hardware CRC unit

Switch from software to hardware for CRC computation. I think this
must be faster, right?

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/usbtrng-v2.0/Makefile b/src/usbtrng-v2.0/Makefile
index 2806d377a97bb9567a787cb2ecedd6a037b46fd4..abbdbbcc1207cb30c56755e2fe6da99c82e78027 100644 (file)
--- a/src/usbtrng-v2.0/Makefile
+++ b/src/usbtrng-v2.0/Makefile
@@ -24,6 +24,7 @@ ALTOS_SRC = \
        ao_mutex.c \
        ao_dma_stm.c \
        ao_adc_fast.c \
+       ao_crc_stm.c \
        ao_stdio.c \
        ao_led.c \
        ao_romconfig.c \

diff --git a/src/usbtrng-v2.0/ao_pins.h b/src/usbtrng-v2.0/ao_pins.h
index 90efb8642877a0dea25619943f9c1f0081190c03..f22678be2615fc22564ae4f596454072dc39db15 100644 (file)
--- a/src/usbtrng-v2.0/ao_pins.h
+++ b/src/usbtrng-v2.0/ao_pins.h
@@ -55,4 +55,8 @@
 
 #define AO_NUM_ADC             1
 
+/* CRC */
+#define AO_CRC_WIDTH   32
+#define AO_CRC_INIT    0xffffffff
+
 #endif /* _AO_PINS_H_ */

diff --git a/src/usbtrng-v2.0/ao_usbtrng.c b/src/usbtrng-v2.0/ao_usbtrng.c
index c5ed5603b86a4fc3c8f00173f039a14f48bfaebd..26cfbac92953cc0d9da28d3253199891e328662e 100644 (file)
--- a/src/usbtrng-v2.0/ao_usbtrng.c
+++ b/src/usbtrng-v2.0/ao_usbtrng.c
@@ -17,54 +17,19 @@
 
 #include <ao.h>
 #include <ao_adc_fast.h>
-
-static const uint16_t crc16_table[256] = {
-       0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
-       0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
-       0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
-       0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
-       0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
-       0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
-       0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
-       0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
-       0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
-       0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
-       0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
-       0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
-       0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
-       0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
-       0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
-       0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
-       0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
-       0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
-       0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
-       0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
-       0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
-       0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
-       0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
-       0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
-       0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
-       0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
-       0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
-       0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
-       0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
-       0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
-       0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
-       0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040,
-};
+#include <ao_crc.h>
 
 static void
 ao_trng_fetch(void)
 {
        static uint16_t *buffer[2];
-       static uint16_t adc_in[AO_USB_IN_SIZE]; /* twice as many as we need */
+       static uint32_t adc_in[AO_USB_IN_SIZE/2];       /* twice as many as we need */
        uint32_t        kbytes = 1;
        uint32_t        count;
        int             usb_buf_id;
-       int             i, j;
-       uint16_t        crc16 = 0;
+       int             i;
        uint16_t        *buf;
-       uint8_t         *rnd;
+       uint32_t        *rnd;
 
        if (!buffer[0]) {
                buffer[0] = ao_usb_alloc();
@@ -80,16 +45,16 @@ ao_trng_fetch(void)
                ao_cmd_status = ao_cmd_success;
        usb_buf_id = 0;
        count = kbytes * (1024/AO_USB_IN_SIZE);
+
+       ao_crc_reset();
+
        ao_led_on(AO_LED_GREEN);
        while (count--) {
-               ao_adc_read(adc_in, AO_USB_IN_SIZE);
-               rnd = (uint8_t *) adc_in;
+               ao_adc_read((uint16_t *) adc_in, AO_USB_IN_SIZE);
+               rnd = adc_in;
                buf = buffer[usb_buf_id];
-               for (i = 0; i < 32; i++) {
-                       for (j = 0; j < 4; j++)
-                               crc16 = (crc16 >> 8) ^ crc16_table[(crc16 ^ *rnd++) & 0xff];
-                       *buf++ = crc16;
-               }
+               for (i = 0; i < 32; i++)
+                       *buf++ = ao_crc_in_32_out_16(*rnd++);
                ao_led_toggle(AO_LED_GREEN|AO_LED_RED);
                ao_usb_write(buffer[usb_buf_id], AO_USB_IN_SIZE);
                ao_led_toggle(AO_LED_GREEN|AO_LED_RED);
@@ -100,7 +65,7 @@ ao_trng_fetch(void)
 }
 
 static const struct ao_cmds usbtrng_cmds[] = {
-       { ao_trng_fetch,        "f\0Fetch a block of numbers" },
+       { ao_trng_fetch,        "f <kbytes>\0Fetch a block of numbers" },
        { 0, NULL },
 };
 
@@ -113,6 +78,7 @@ void main(void)
        ao_timer_init();
        ao_dma_init();
        ao_adc_init();
+       ao_crc_init();
 
        ao_cmd_init();