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[MIPS] BCM1250: TRDY timeout tweaks for Broadcom SiByte systems 

It was obesrved that at least one older PCI card predating the
requirement for the TRDY signal to respond within 16 clock ticks actually
does not meet this rule nor even the power-on defaults of the PCI bridges
found in development systems built around the Broadcom SiByte SOCs.  Here
is a patch that bumps up the timeout to the highest finite value supported
by these chips, which is 255 clock ticks.  The bridges affected are the
SiByte SOC itself and the SP1011.
    
 This change does not effectively affect systems only having PCI option
cards installed that meet the TRDY requirement of the current PCI spec.
The rule was introduced with PCI 2.1, so any older card may make the
system affected.  If this is the case, performance of the system will
suffer in return for the card working at all.  If this is a concern, then
the solution is not to use such cards.
    
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

---
This commit is contained in:
Maciej W. Rozycki 2006-10-02 12:55:09 +01:00 committed by Ralf Baechle
parent 3a42aa9348
commit 15a1c51404
2 changed files with 25 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
arch/mips/pci/fixup-sb1250.c
View File

@ -1,7 +1,7 @@
/*
* arch/mips/pci/fixup-sb1250.c
*
* Copyright (C) 2004 MIPS Technologies, Inc. All rights reserved.
* Copyright (C) 2004, 2006 MIPS Technologies, Inc. All rights reserved.
* Author: Maciej W. Rozycki <macro@mips.com>
*
* This program is free software; you can redistribute it and/or
@ -13,6 +13,17 @@
#include <linux/init.h>
#include <linux/pci.h>
/*
* Set the the BCM1250, etc. PCI host bridge's TRDY timeout
* to the finite max.
*/
static void __init quirk_sb1250_pci(struct pci_dev *dev)
{
pci_write_config_byte(dev, 0x40, 0xff);
}
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI,
quirk_sb1250_pci);
/*
* The BCM1250, etc. PCI/HT bridge reports as a host bridge.
*/
@ -22,3 +33,13 @@ static void __init quirk_sb1250_ht(struct pci_dev *dev)
}
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_HT,
quirk_sb1250_ht);
/*
* Set the the SP1011 HT/PCI bridge's TRDY timeout to the finite max.
*/
static void __init quirk_sp1011(struct pci_dev *dev)
{
pci_write_config_byte(dev, 0x64, 0xff);
}
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIPACKETS, PCI_DEVICE_ID_SP1011,
quirk_sp1011);

3
include/linux/pci_ids.h
View File

@ -1883,6 +1883,8 @@
#define PCI_DEVICE_ID_PANACOM_QUADMODEM 0x0400
#define PCI_DEVICE_ID_PANACOM_DUALMODEM 0x0402
#define PCI_VENDOR_ID_SIPACKETS 0x14d9
#define PCI_DEVICE_ID_SP1011 0x0010
#define PCI_VENDOR_ID_AFAVLAB 0x14db
#define PCI_DEVICE_ID_AFAVLAB_P028 0x2180
@ -1997,6 +1999,7 @@
#define PCI_DEVICE_ID_FARSITE_TE1C 0x1612
#define PCI_VENDOR_ID_SIBYTE 0x166d
#define PCI_DEVICE_ID_BCM1250_PCI 0x0001
#define PCI_DEVICE_ID_BCM1250_HT 0x0002
#define PCI_VENDOR_ID_NETCELL 0x169c