ubb-patgen/: add DMA-based pattern transfer (WIP)

Works for some patterns but seems to have issues at the edge of
transfers. Clock selection also needs more work.

ubb-patgen/ubb-patgen.c

@@ -14,11 +14,18 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <string.h>
 #include <math.h>
 #include <time.h>
+#include <assert.h>
 
 #include <ubb/ubb.h>
+#include <ubb/regs4740.h>
 #include <ubb/mmcclk.h>
+#include <ubb/physmem.h>
+
+
+#define	DMA	5
 
 
 /* ----- List available bus clock frequencies ------------------------------ */
@@ -122,6 +129,142 @@ static int select_freq(struct mmcclk *res, int hz, int rel)
 }
 
 
+/* ----- DMA the pattern --------------------------------------------------- */
+
+
+static uint32_t old_dmac;
+
+
+static void dma_stop(void)
+{
+	DCS(DMA) = (1 << 3) | (1 << 2);	/* halt DMA channel */
+	DCS(DMA) = 0;			/* reset DMA channel */
+}
+
+
+static void dma_init(void)
+{
+	old_dmac = DMAC;
+
+	DMAC = 1;	/* activate the DMA controller (in case it's off) */
+	dma_stop();
+
+	DCM(DMA) =
+	    (1 << 23) |	/* source address increment */
+	    (4 << 8);	/* transfer size is 32 bytes */
+	DRT(DMA) = 26;	/* MSC transmit-fifo-empty transfer request */
+}
+
+
+static void dma_cleanup(void)
+{
+	DMAC = old_dmac;
+	dma_stop();
+}
+
+
+static void dma_setup(unsigned long buf, int nibbles)
+{
+	assert(!(nibbles & 63));
+
+	DCS(DMA) = 1 << 31;			/* no-descriptor transfer */
+	DSA(DMA) = buf;				/* source */
+	DTA(DMA) = REG_PADDR(MSC_TXFIFO);	/* MUST set this each time */
+	DTC(DMA) = nibbles >> 6;		/* 32 bytes per transfer */
+}
+
+
+static void mmc_buffer(const struct mmcclk *clk,
+    unsigned long buf, int nibbles)
+{
+	MSC_STRPCL = 1 << 3;	/* reset the MSC */
+
+	while (MSC_STAT & (1 << 15));	/* wait until reset finishes */
+
+	dma_setup(buf, nibbles);
+
+	MSC_CLKRT = clk->clkrt;	/* cleared by MSC reset */
+	MSC_STRPCL = 2;		/* start the bus clock */
+	MSC_RESTO = 0xffff;	/* maximum response time-out */
+
+	MSC_CMDAT =
+	    (2 << 9) |		/* 4 bit bus */
+	    (1 << 8) |		/* DMA */
+	    (1 << 4) |		/* write */
+	    (1 << 3) |		/* with data transfer */
+	    1;			/* R1 response */
+
+        MSC_STRPCL = 4;         /* START_OP */
+
+	DCS(DMA) =
+	    (1 << 31) |         /* no descriptor */
+	    1;			/* enable transfer */
+
+	usleep(100);
+
+	sleep(1);
+
+	printf("MSC_STAT 0x%x\n", MSC_STAT);
+}
+
+
+static void send_buffer(const struct mmcclk *clk,
+    const uint8_t *buf, int nibbles)
+{
+	unsigned long phys;
+
+	phys = physmem_xlat((void *) buf);
+	mmc_buffer(clk, phys, nibbles);
+}
+
+
+static int dma_pattern(const struct mmcclk *clk,
+    const char *pattern, uint32_t mask)
+{
+	int n = strlen(pattern);
+	int rounded = (n+63) & ~63;
+	uint8_t *buf = physmem_malloc(rounded >> 1);
+	uint8_t *tmp = physmem_malloc(32);
+	int i;
+
+	if (!n)
+		return 1;
+
+	memset(buf, 0, rounded);
+	for (i = 0; i != rounded; i++) {
+		char ch[2] = { pattern[i < n ? i : n-1], 0 };
+		char *end;
+
+		buf[i >> 1] |= strtoul(ch, &end, 16) << 4*(~i & 1);
+		if (*end)
+			return 0;
+	}
+
+	dma_init();
+
+	PDDATC = ~((buf[0] >> 4) << 10) & mask;
+	PDDATS = (buf[0] >> 4) << 10;
+	PDDIRS = mask;
+
+	memset(tmp, (buf[0] >> 4)*0x11, 64);
+
+	send_buffer(clk, tmp, 64);
+
+	PDFUNS = mask;
+
+	send_buffer(clk, buf, rounded);
+
+	PDDATC = ~((buf[(rounded >> 1)-1] & 0xf) << 10) & mask;
+	PDDATS = (buf[(rounded >> 1)-1] & 0xf) << 10;
+
+	PDFUNC = mask;
+
+	dma_cleanup();
+
+	return 1;
+}
+
+
 /* ----- Command-line processing ------------------------------------------- */
 
 
@@ -174,15 +317,18 @@ static void usage(const char *name)
 {
         fprintf(stderr,
 "usage: %s\n"
-"usage: %s [-b freq_hz] [-c] [-q] active_s\n\n"
+"usage: %s [-b freq_hz] [-f freq_hz] [-c] [-q] [pattern] active_s\n\n"
 "  -b freq_hz  set bus clock to the specified frequency (default: 1 MHz)\n"
 "  -c          output bus clock on CLK\n"
+"  -f freq_hz  set pattern rate (default: same as bus clock)\n"
 "  -q          quiet. Don't report clock differences.\n\n"
-"  active_s    keep running that many seconds after setting the clock\n\n"
+"  active_s    keep running that many seconds after setting the clock\n"
+"  pattern     send the specified pattern on DAT0 through DAT3\n\n"
 "Frequency: the frequency in Hz, optionally followed by \"M\" or \"k\",\n"
 "  optionally followed by \"Hz\", optionally followed by \"+\" or \"-\".\n"
 "  \"+\" selects a frequency >= the specified one, \"-\" one <=.\n"
 "  Without +/-, the closest available frequency is selected.\n"
+"Pattern: hex digits corresponding to 1 for DAT0, 2 for DAT1, etc.\n"
     , name, name);
 	exit(1);
 }
@@ -191,7 +337,9 @@ static void usage(const char *name)
 int main(int argc, char **argv)
 {
 	struct mmcclk clk;
-	int bus_hz = 1000000, clkout = 0, rel = 0;
+	int bus_hz = 0, clkout = 0, bus_rel = 0;
+	int pattern_hz = 0, pattern_rel = 0;
+	const char *pattern = NULL;
 	int quiet = 0;
 	double active_s;
 	struct timespec active_ns;
@@ -201,7 +349,11 @@ int main(int argc, char **argv)
 	while ((c = getopt(argc, argv, "b:cq")) != EOF)
 		switch (c) {
 		case 'b':
-			if (!frequency(optarg, &bus_hz, &rel))
+			if (!frequency(optarg, &bus_hz, &bus_rel))
+				usage(*argv);
+			break;
+		case 'f':
+			if (!frequency(optarg, &pattern_hz, &pattern_rel))
 				usage(*argv);
 			break;
 		case 'c':
@@ -221,8 +373,11 @@ int main(int argc, char **argv)
 		ubb_open(UBB_ALL);
 		show_frequencies();
 		return 1;
+	case 2:
+		pattern = argv[optind];
+		/* fall through */
 	case 1:
-		active_s = strtod(argv[optind], &end);
+		active_s = strtod(argv[argc-1], &end);
 		if (*end)
 			usage(*argv);
 		active_ns.tv_sec = (int) active_s;
@@ -234,7 +389,12 @@ int main(int argc, char **argv)
 
 	ubb_open(UBB_ALL);
 
-	if (!select_freq(&clk, bus_hz, rel)) {
+	PDFUNS = UBB_CMD;
+
+	if (!bus_hz)
+		bus_hz = 1000000;
+
+	if (!select_freq(&clk, bus_hz, bus_rel)) {
 		fprintf(stderr, "no suitable frequency found\n");
 		exit(1);
 	}
@@ -254,12 +414,17 @@ int main(int argc, char **argv)
 		PDFUNS = UBB_CLK;
 	mmcclk_start(&clk);
 
+	if (pattern)
+		if (!dma_pattern(&clk, pattern,
+		    UBB_DAT0 | UBB_DAT1 | UBB_DAT2 | UBB_DAT3))
+			usage(*argv);
+
 	if (nanosleep(&active_ns, NULL))
 		perror("nanosleep");
 
 	mmcclk_stop();
 
-	ubb_close(0);
+	ubb_close(UBB_DAT0 | UBB_DAT1 | UBB_DAT2 | UBB_DAT3);
 
 	return 0;
 }