DM9000: Make driver work properly for DM9000A
The DM9000A network controller does not work with the U-boot DM9000x driver.
Analysis showed that many incoming packets are lost.
The DM9000A Application Notes V1.20 (section 5.6.1) recommend that the poll to
check for a valid rx packet be done on the interrupt status register, not
directly by performing the dummy read and the rx status check as is currently
the case in the u-boot driver.
When the recommended poll is done as suggested the driver starts working
correctly on 10Mbit/HD, but on 100MBit/FD packets come in faster so that there
can be more than 1 package in the fifo at the same time.
The driver must perform the rx-status check in a loop and read and handle all
packages until there is no more left _after_ the interrupt RX flag is set.
This change has been tested with DM9000A, DM9000E, DM9000EP.
Signed-off-by: Remy Bohmer <linux@bohmer.net>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
diff --git a/drivers/net/dm9000x.c b/drivers/net/dm9000x.c
index 5b00e95..08248f4 100644
--- a/drivers/net/dm9000x.c
+++ b/drivers/net/dm9000x.c
@@ -40,6 +40,10 @@
Sascha Hauer <saschahauer@web.de>
06/03/2008 Remy Bohmer <linux@bohmer.net>
+ - Fixed the driver to work with DM9000A.
+ (check on ISR receive status bit before reading the
+ FIFO as described in DM9000 programming guide and
+ application notes)
- Added autodetect of databus width.
- Made debug code compile again.
- Adapt eth_send such that it matches the DM9000*
@@ -598,53 +602,64 @@
u16 RxStatus, RxLen = 0;
struct board_info *db = &dm9000_info;
- /* Check packet ready or not */
- DM9000_ior(DM9000_MRCMDX); /* Dummy read */
- rxbyte = DM9000_inb(DM9000_DATA); /* Got most updated data */
- if (rxbyte == 0)
+ /* Check packet ready or not, we must check
+ the ISR status first for DM9000A */
+ if (!(DM9000_ior(DM9000_ISR) & 0x01)) /* Rx-ISR bit must be set. */
return 0;
- /* Status check: this byte must be 0 or 1 */
- if (rxbyte > 1) {
- DM9000_iow(DM9000_RCR, 0x00); /* Stop Device */
- DM9000_iow(DM9000_ISR, 0x80); /* Stop INT request */
- DM9000_DBG("rx status check: %d\n", rxbyte);
- }
- DM9000_DBG("receiving packet\n");
+ DM9000_iow(DM9000_ISR, 0x01); /* clear PR status latched in bit 0 */
- /* A packet ready now & Get status/length */
- DM9000_outb(DM9000_MRCMD, DM9000_IO);
+ /* There is _at least_ 1 package in the fifo, read them all */
+ for (;;) {
+ DM9000_ior(DM9000_MRCMDX); /* Dummy read */
- (db->rx_status)(&RxStatus, &RxLen);
+ /* Get most updated data */
+ rxbyte = DM9000_inb(DM9000_DATA);
- DM9000_DBG("rx status: 0x%04x rx len: %d\n", RxStatus, RxLen);
+ /* Status check: this byte must be 0 or 1 */
+ if (rxbyte > DM9000_PKT_RDY) {
+ DM9000_iow(DM9000_RCR, 0x00); /* Stop Device */
+ DM9000_iow(DM9000_ISR, 0x80); /* Stop INT request */
+ printf("DM9000 error: status check fail: 0x%x\n",
+ rxbyte);
+ return 0;
+ }
- /* Move data from DM9000 */
- /* Read received packet from RX SRAM */
- (db->inblk)(rdptr, RxLen);
+ if (rxbyte != DM9000_PKT_RDY)
+ return 0; /* No packet received, ignore */
- if ((RxStatus & 0xbf00) || (RxLen < 0x40)
- || (RxLen > DM9000_PKT_MAX)) {
- if (RxStatus & 0x100) {
- printf("rx fifo error\n");
- }
- if (RxStatus & 0x200) {
- printf("rx crc error\n");
- }
- if (RxStatus & 0x8000) {
- printf("rx length error\n");
- }
- if (RxLen > DM9000_PKT_MAX) {
- printf("rx length too big\n");
- dm9000_reset();
- }
- } else {
- DM9000_DMP_PACKET("eth_rx", rdptr, RxLen);
+ DM9000_DBG("receiving packet\n");
+
+ /* A packet ready now & Get status/length */
+ (db->rx_status)(&RxStatus, &RxLen);
- /* Pass to upper layer */
- DM9000_DBG("passing packet to upper layer\n");
- NetReceive(NetRxPackets[0], RxLen);
- return RxLen;
+ DM9000_DBG("rx status: 0x%04x rx len: %d\n", RxStatus, RxLen);
+
+ /* Move data from DM9000 */
+ /* Read received packet from RX SRAM */
+ (db->inblk)(rdptr, RxLen);
+
+ if ((RxStatus & 0xbf00) || (RxLen < 0x40)
+ || (RxLen > DM9000_PKT_MAX)) {
+ if (RxStatus & 0x100) {
+ printf("rx fifo error\n");
+ }
+ if (RxStatus & 0x200) {
+ printf("rx crc error\n");
+ }
+ if (RxStatus & 0x8000) {
+ printf("rx length error\n");
+ }
+ if (RxLen > DM9000_PKT_MAX) {
+ printf("rx length too big\n");
+ dm9000_reset();
+ }
+ } else {
+ DM9000_DMP_PACKET("eth_rx", rdptr, RxLen);
+
+ DM9000_DBG("passing packet to upper layer\n");
+ NetReceive(NetRxPackets[0], RxLen);
+ }
}
return 0;
}