[U-Boot] [PATCH] 83xx: PCI agent mode fixes for multi-board systems

[U-Boot] [PATCH] 83xx: PCI agent mode fixes for multi-board systems

[Ira Snyder]

When running a system with 2 or more MPC8349EMDS boards in PCI agent mode,
the boards will lock up the PCI bus by scanning against each other.

The boards lock against each other by trying to access the PCI bus before
clearing their configuration lock bit. Both boards end up in a loop,
sending and receiving "Target Not Ready" messages forever.

When running in PCI agent mode, the scanning now takes place after the
boards have cleared their configuration lock bit.

Also, add a missing declaration to the mpc83xx.h header file, fixing a
build warning.

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
---
 cpu/mpc83xx/pci.c |    5 +++++
 include/mpc83xx.h |    1 +
 2 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/cpu/mpc83xx/pci.c b/cpu/mpc83xx/pci.c
index ab0760b..e9965d7 100644
--- a/cpu/mpc83xx/pci.c
+++ b/cpu/mpc83xx/pci.c
@@ -118,10 +118,12 @@ static void pci_init_bus(int bus, struct pci_region *reg)
 #ifdef CONFIG_PCI_SCAN_SHOW
 	printf("PCI:   Bus Dev VenId DevId Class Int\n");
 #endif
+#ifndef CONFIG_PCISLAVE
 	/*
 	 * Hose scan.
 	 */
 	hose->last_busno = pci_hose_scan(hose);
+#endif
 }
 
 /*
@@ -190,6 +192,9 @@ void mpc83xx_pcislave_unlock(int bus)
 	pci_hose_read_config_word (hose, dev, PCI_FUNCTION_CONFIG, &reg16);
 	reg16 &= ~(PCI_FUNCTION_CFG_LOCK);
 	pci_hose_write_config_word (hose, dev, PCI_FUNCTION_CONFIG, reg16);
+
+	/* The configuration bit is now unlocked, so we can scan the bus */
+	hose->last_busno = pci_hose_scan(hose);
 }
 #endif
 
diff --git a/include/mpc83xx.h b/include/mpc83xx.h
index 43553f5..e5dfe3f 100644
--- a/include/mpc83xx.h
+++ b/include/mpc83xx.h
@@ -1173,6 +1173,7 @@
 #ifndef __ASSEMBLY__
 struct pci_region;
 void mpc83xx_pci_init(int num_buses, struct pci_region **reg, int warmboot);
+void mpc83xx_pcislave_unlock(int bus);
 #endif
 
 #endif	/* __MPC83XX_H__ */
-- 
1.5.4.3

[U-Boot] [PATCH] 83xx: PCI agent mode fixes for multi-board systems

[Kim Phillips]

On Mon, 12 Jan 2009 13:32:26 -0800
Ira Snyder <iws@ovro.caltech.edu> wrote:

> When running a system with 2 or more MPC8349EMDS boards in PCI agent mode,
> the boards will lock up the PCI bus by scanning against each other.
> 
> The boards lock against each other by trying to access the PCI bus before
> clearing their configuration lock bit. Both boards end up in a loop,
> sending and receiving "Target Not Ready" messages forever.
> 
> When running in PCI agent mode, the scanning now takes place after the
> boards have cleared their configuration lock bit.
> 
> Also, add a missing declaration to the mpc83xx.h header file, fixing a
> build warning.
> 
> Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
> ---

applied to u-boot-mpc83xx next.

Thanks,

Kim