Use shutdown callback mechanism to shutdown programmers

This patch attempts to resolve some programmer shutdown ordering issues
by having the programmer init functions register shutdown callbacks explicitly
wherever it makes most sense. Before, assumptions were made that could lead to
the internal programmer's state changing before the external programmer could be
shut down properly. Now, each programmer cleans up after itself and (hopefully)
performs each operation in the correct order.

As a side-effect, this patch gives us a better usage model for reverse
operations such as rpci_* and rmmio_*. In the long-run, this should make
reversing the initialization process easier to understand, less tedious, and
less error-prone.

In short, this patch does the following:
- Registers a shutdown callback during initialization for each programmer.
- Kills the .shutdown function pointer from programmer_entry struct. Also,
  make most shutdown functions static.
- Adds a few minor clean-ups and corrections (e.g. missing physunmap() calls).

TODO: Remove forward declaration of serprog_shutdown() (added to simplify diff)

Corresponding to flashrom svn r1338.

Signed-off-by: David Hendricks <dhendrix@google.com>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>

1 files changed, 38 insertions, 35 deletions

diff --git a/buspirate_spi.c b/buspirate_spi.c
index 3ac0929..3b9f487 100644
--- a/buspirate_spi.c
+++ b/buspirate_spi.c
@@ -111,6 +111,41 @@ static const struct buspirate_spispeeds spispeeds[] = {
 	{NULL,		0x0}
 };
 
+static int buspirate_spi_shutdown(void *data)
+{
+	unsigned char buf[5];
+	int ret = 0;
+
+	/* Exit raw SPI mode (enter raw bitbang mode) */
+	buf[0] = 0x00;
+	ret = buspirate_sendrecv(buf, 1, 5);
+	if (ret)
+		return ret;
+	if (memcmp(buf, "BBIO", 4)) {
+		msg_perr("Entering raw bitbang mode failed!\n");
+		return 1;
+	}
+	msg_pdbg("Raw bitbang mode version %c\n", buf[4]);
+	if (buf[4] != '1') {
+		msg_perr("Can't handle raw bitbang mode version %c!\n",
+			buf[4]);
+		return 1;
+	}
+	/* Reset Bus Pirate (return to user terminal) */
+	buf[0] = 0x0f;
+	ret = buspirate_sendrecv(buf, 1, 0);
+	if (ret)
+		return ret;
+
+	/* Shut down serial port communication */
+	ret = serialport_shutdown(NULL);
+	if (ret)
+		return ret;
+	msg_pdbg("Bus Pirate shutdown completed.\n");
+
+	return 0;
+}
+
 int buspirate_spi_init(void)
 {
 	unsigned char buf[512];
@@ -148,6 +183,9 @@ int buspirate_spi_init(void)
 		return ret;
 	free(dev);
 
+	if (register_shutdown(buspirate_spi_shutdown, NULL))
+		return 1;
+
 	/* This is the brute force version, but it should work. */
 	for (i = 0; i < 19; i++) {
 		/* Enter raw bitbang mode */
@@ -253,41 +291,6 @@ int buspirate_spi_init(void)
 	return 0;
 }
 
-int buspirate_spi_shutdown(void)
-{
-	unsigned char buf[5];
-	int ret = 0;
-
-	/* Exit raw SPI mode (enter raw bitbang mode) */
-	buf[0] = 0x00;
-	ret = buspirate_sendrecv(buf, 1, 5);
-	if (ret)
-		return ret;
-	if (memcmp(buf, "BBIO", 4)) {
-		msg_perr("Entering raw bitbang mode failed!\n");
-		return 1;
-	}
-	msg_pdbg("Raw bitbang mode version %c\n", buf[4]);
-	if (buf[4] != '1') {
-		msg_perr("Can't handle raw bitbang mode version %c!\n",
-			buf[4]);
-		return 1;
-	}
-	/* Reset Bus Pirate (return to user terminal) */
-	buf[0] = 0x0f;
-	ret = buspirate_sendrecv(buf, 1, 0);
-	if (ret)
-		return ret;
-
-	/* Shut down serial port communication */
-	ret = serialport_shutdown();
-	if (ret)
-		return ret;
-	msg_pdbg("Bus Pirate shutdown completed.\n");
-
-	return 0;
-}
-
 static int buspirate_spi_send_command(unsigned int writecnt, unsigned int readcnt,
 		const unsigned char *writearr, unsigned char *readarr)
 {