The ColdFire PCI configuration space access functions swap addressing
regions to do their work. Just letting the read/write cycles exit
the CPU core (via the ColdFire "nop" instruction) is not enough to
guarantee that the address region remapping has actually completed.
Insert a read back of the mapping register to be absolutely sure
that the remapping has completed.
This fixes an occasional boot hang during the ColdFire PCI initialization
phase.
Signed-off-by: Greg Ungerer <gerg@xxxxxxxxxxxxxx>
Reviewed-by: Angelo Dureghello <angelo@xxxxxxxx>
---
arch/m68k/coldfire/pci.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)
v2: rebase to v4.17-rc1
fix compilation warnings
drop read/write iomem() conversions
diff --git a/arch/m68k/coldfire/pci.c b/arch/m68k/coldfire/pci.c
index db709ad..62b0eb6 100644
--- a/arch/m68k/coldfire/pci.c
+++ b/arch/m68k/coldfire/pci.c
@@ -46,13 +46,6 @@
0, 69, 69, 71, 71,
};
-
-static inline void syncio(void)
-{
- /* The ColdFire "nop" instruction waits for all bus IO to complete */
- __asm__ __volatile__ ("nop");
-}
-
/*
* Configuration space access functions. Configuration space access is
* through the IO mapping window, enabling it via the PCICAR register.
@@ -74,9 +67,9 @@ static int mcf_pci_readconfig(struct pci_bus *bus, unsigned int devfn,
return PCIBIOS_SUCCESSFUL;
}
- syncio();
addr = mcf_mk_pcicar(bus->number, devfn, where);
__raw_writel(PCICAR_E | addr, PCICAR);
+ __raw_readl(PCICAR);
addr = iospace + (where & 0x3);
switch (size) {
@@ -91,8 +84,8 @@ static int mcf_pci_readconfig(struct pci_bus *bus, unsigned int devfn,
break;
}
- syncio();
__raw_writel(0, PCICAR);
+ __raw_readl(PCICAR);
return PCIBIOS_SUCCESSFUL;
}
@@ -106,9 +99,9 @@ static int mcf_pci_writeconfig(struct pci_bus *bus, unsigned int devfn,
return PCIBIOS_SUCCESSFUL;
}
- syncio();
addr = mcf_mk_pcicar(bus->number, devfn, where);
__raw_writel(PCICAR_E | addr, PCICAR);
+ __raw_readl(PCICAR);
addr = iospace + (where & 0x3);
switch (size) {
@@ -123,8 +116,8 @@ static int mcf_pci_writeconfig(struct pci_bus *bus, unsigned int devfn,
break;
}
- syncio();
__raw_writel(0, PCICAR);
+ __raw_readl(PCICAR);
return PCIBIOS_SUCCESSFUL;
}
--
1.9.1
--
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