[PATCH] K8T890: wait for pcie link to come up - coreboot

22 Nov 2010

With low serial console loglevels a pcie graphics card is not
initialized properly because the pcie link takes some time to come
up.
I set the timeout rather arbitrary to 100ms, this is what a BIOS_ERR
and higher only boot looks like on my system (with pcie printks set
to BIOS_ERR so they show up):
|Device error
|Device error
|PCI: 00:02.0 PCIe link up after 35800 us
|PCI: 00:03.0 PCIe link up after 12900 us
|PCI: 00:03.1 PCIe link timeout
|PCI: 00:03.2 PCIe link up after 32000 us
|APIC: 00 missing read_resources
|I2C: 01:50 missing read_resources
|I2C: 01:51 missing read_resources
|I2C: 01:52 missing read_resources
|I2C: 01:53 missing read_resources
|Start bios (version pre-0.6.2-20101025_023503-nukunuku)
Signed-off-by: Tobias Diedrich ranma+coreboot@tdiedrich.de
---
Index: src/southbridge/via/k8t890/k8t890_pcie.c
===================================================================

--- src/southbridge/via/k8t890/k8t890_pcie.c.orig	2010-11-22 15:24:12.000000000 +0100
+++ src/southbridge/via/k8t890/k8t890_pcie.c	2010-11-22 15:27:23.000000000 +0100
@@ -22,6 +22,7 @@
 #include <device/pci.h>
 #include <device/pciexp.h>
 #include <device/pci_ids.h>
+#include <delay.h>
 #include "k8t890.h"
/*
@@ -30,16 +31,10 @@
  * http://linux.via.com.tw/
  */
-static void peg_init(struct device *dev)
+static void pcie_common_init(struct device *dev)
 {
    u8 reg;
-
-	printk(BIOS_DEBUG, "Configuring PCIe PEG\n");
-	dump_south(dev);
-
-	/* Disable link. */
-	reg = pci_read_config8(dev, 0x50);
-	pci_write_config8(dev, 0x50, reg | 0x10);
+	int i, up;
/* Disable downstream read cycle retry,
     * otherwise the bus scan will hang if no device is plugged in. */
@@ -60,14 +55,48 @@
     */
    pci_write_config8(dev, 0xe1, 0xb);
+	/* Set replay timer limit. */
+	pci_write_config8(dev, 0xb1, 0xf0);
+
+	/* Enable link. */
+	reg = pci_read_config8(dev, 0x50);
+	pci_write_config8(dev, 0x50, reg & ~0x10);
+
+	/* Wait up to 100ms for link to come up */
+	up = 0;
+	for (i=0; i<1000; i++) {
+		if (pci_read_config16(dev, 0x52) & (1<<13)) {
+			up = 1;
+			break;
+		}
+		udelay(100);
+	}
+
+	printk(BIOS_SPEW, "%s PCIe link ", dev_path(dev));
+	if (up)
+		printk(BIOS_SPEW, "up after %d us\n", i*100);
+	else
+		printk(BIOS_SPEW, "timeout\n");
+
+	dump_south(dev);
+}
+
+static void peg_init(struct device *dev)
+{
+	u8 reg;
+
+	printk(BIOS_DEBUG, "Configuring PCIe PEG\n");
+	dump_south(dev);
+
+	/* Disable link. */
+	reg = pci_read_config8(dev, 0x50);
+	pci_write_config8(dev, 0x50, reg | 0x10);
+
    /*
     * pci_write_config8(dev, 0xe2, 0x0);
     * pci_write_config8(dev, 0xe3, 0x92);
     */
-	/* Set replay timer limit. */
-	pci_write_config8(dev, 0xb1, 0xf0);
-
    /* Bit0 = 1 SDP (Start DLLP) always at Lane0. */
    reg = pci_read_config8(dev, 0xb8);
    pci_write_config8(dev, 0xb8, reg | 0x1);
@@ -79,11 +108,7 @@
    reg = pci_read_config8(dev, 0xa4);
    pci_write_config8(dev, 0xa4, reg | 0x30);
-	/* Enable link. */
-	reg = pci_read_config8(dev, 0x50);
-	pci_write_config8(dev, 0x50, reg & ~0x10);
-
-	dump_south(dev);
+	pcie_common_init(dev);
 }
static void pcie_init(struct device *dev)
@@ -97,33 +122,7 @@
    reg = pci_read_config8(dev, 0x50);
    pci_write_config8(dev, 0x50, reg | 0x10);
-	/* 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);
-
-	/* Enable link. */
-	reg = pci_read_config8(dev, 0x50);
-	pci_write_config8(dev, 0x50, reg & ~0x10);
-
-	dump_south(dev);
+	pcie_common_init(dev);
 }
static const struct device_operations peg_ops = {

    