[coreboot] [PATCH 5/7] ASUS M2V support (v2): K8T890 PCIe bugfix

Tobias Diedrich ranma+coreboot at tdiedrich.de
Fri Oct 29 14:01:49 CEST 2010


Need to clear downstream read cycle retry bit, or the bus scan will
hang.  Also need to set lane config to 0x00 for autonegotiation.

Signed-off-by: Tobias Diedrich <ranma+coreboot at tdiedrich.de>

---

Index: src/southbridge/via/k8t890/k8t890_pcie.c
===================================================================
--- src/southbridge/via/k8t890/k8t890_pcie.c.orig	2010-10-29 13:36:04.000000000 +0200
+++ src/southbridge/via/k8t890/k8t890_pcie.c	2010-10-29 13:45:11.000000000 +0200
@@ -35,7 +35,23 @@
 	reg = pci_read_config8(dev, 0x50);
 	pci_write_config8(dev, 0x50, reg | 0x10);
 
-	/* Award has 0xb, VIA recomends 0x4. */
+	/* Disable downstream read cycle retry,
+	 * otherwise the bus scan will hang if no device is plugged in. */
+	reg = pci_read_config8(dev, 0xa3);
+	pci_write_config8(dev, 0xa3, reg & ~0x01);
+
+	/* Use PHY negotiation for lane config */
+	reg = pci_read_config8(dev, 0xc1);
+	pci_write_config8(dev, 0xc1, reg & ~0x1f);
+
+	/* Award has 0xb, VIA recommends 0xd, default 0x8.
+	 * bit4: receive polarity change control
+	 * bits3:2: squelch window select 64~175mv
+	 * bit1: Number of non-idle bits detected before exiting idle state
+	 *       0: 10 bits, 1: 2 bits
+	 * bit0: Number of idle bits detected before entering idle state
+	 *       0: 10 bits, 1: 2 bits
+	 */
 	pci_write_config8(dev, 0xe1, 0xb);
 
 	/*
@@ -75,8 +91,25 @@
 	reg = pci_read_config8(dev, 0x50);
 	pci_write_config8(dev, 0x50, reg | 0x10);
 
-	/* Award has 0xb, VIA recommends 0x4. */
+	/* Disable downstream read cycle retry,
+	 * otherwise the bus scan will hang if no device is plugged in. */
+	reg = pci_read_config8(dev, 0xa3);
+	pci_write_config8(dev, 0xa3, reg & ~0x01);
+
+	/* Use PHY negotiation for lane config */
+	reg = pci_read_config8(dev, 0xc1);
+	pci_write_config8(dev, 0xc1, reg & ~0x1f);
+
+	/* Award has 0xb, VIA recommends 0xd, default 0x8.
+	 * bit4: receive polarity change control
+	 * bits3:2: squelch window select 64~175mv
+	 * bit1: Number of non-idle bits detected before exiting idle state
+	 *       0: 10 bits, 1: 2 bits
+	 * bit0: Number of idle bits detected before entering idle state
+	 *       0: 10 bits, 1: 2 bits
+	 */
 	pci_write_config8(dev, 0xe1, 0xb);
+
 	/* Set replay timer limit. */
 	pci_write_config8(dev, 0xb1, 0xf0);
 




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