rayer_spi: Fix Xilinx DLC-5 cable

Pin 6 on LPT controls a pulldown on MISO/TDO signal. Whether there exists
an unbuffered clone is unknown. The author of the original patch confirmed
in private correspondence that the patch was incomplete. There has been
no sign of an unbuffered version on the interwebs, hence just change the
existing driver to disable the pulldown.

Corresponding to flashrom svn r1757.

Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

1 files changed, 20 insertions, 0 deletions

diff --git a/rayer_spi.c b/rayer_spi.c
index f8dff95..189341a 100644
--- a/rayer_spi.c
+++ b/rayer_spi.c
@@ -63,11 +63,16 @@ static const struct rayer_pinout rayer_spipgm = {
 	.miso_bit = 6,
 };
 
+static void dlc5_preinit(const void *);
+static int dlc5_shutdown(void *);
+
 static const struct rayer_pinout xilinx_dlc5 = {
 	.cs_bit = 2,
 	.sck_bit = 1,
 	.mosi_bit = 0,
 	.miso_bit = 4,
+	.preinit =  dlc5_preinit,
+	.shutdown = dlc5_shutdown,
 };
 
 static void byteblaster_preinit(const void *);
@@ -257,6 +262,21 @@ static int stk200_shutdown(void *data) {
 	return 0;
 }
 
+static void dlc5_preinit(const void *data) {
+	msg_pdbg("dlc5_preinit\n");
+	/* Assert pin 6 to receive MISO. */
+	lpt_outbyte |= (1<<4);
+	OUTB(lpt_outbyte, lpt_iobase);
+}
+
+static int dlc5_shutdown(void *data) {
+	msg_pdbg("dlc5_shutdown\n");
+	/* De-assert pin 6 to force MISO low. */
+	lpt_outbyte &= ~(1<<4);
+	OUTB(lpt_outbyte, lpt_iobase);
+	return 0;
+}
+
 #else
 #error PCI port I/O access is not supported on this architecture yet.
 #endif