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IXP4xx: Extend PCI MMIO indirect address space to 1 GB.

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IXP4xx CPUs can indirectly access the whole 4 GB PCI MMIO address space (using
the non-prefetch registers). Previously the available space depended on the CPU
variant, since one of the IXP43x platforms needed more than the usual 128 MB.
1 GB should be enough for everyone, and if not, we can trivially increase it.

Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
This commit is contained in:
Krzysztof Hałasa 2009-11-15 18:02:10 +01:00
parent cba362221b
commit ed5b9fa0d1
4 changed files with 29 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
arch/arm/mach-ixp4xx/Kconfig
View File

@ -179,21 +179,21 @@ config IXP4XX_INDIRECT_PCI
help
IXP4xx provides two methods of accessing PCI memory space:
1) A direct mapped window from 0x48000000 to 0x4bffffff (64MB).
1) A direct mapped window from 0x48000000 to 0x4BFFFFFF (64MB).
To access PCI via this space, we simply ioremap() the BAR
into the kernel and we can use the standard read[bwl]/write[bwl]
macros. This is the preferred method due to speed but it
limits the system to just 64MB of PCI memory. This can be
limits the system to just 64MB of PCI memory. This can be
problematic if using video cards and other memory-heavy devices.
2) If > 64MB of memory space is required, the IXP4xx can be
configured to use indirect registers to access PCI This allows
for up to 128MB (0x48000000 to 0x4fffffff) of memory on the bus.
The disadvantage of this is that every PCI access requires
three local register accesses plus a spinlock, but in some
cases the performance hit is acceptable. In addition, you cannot
mmap() PCI devices in this case due to the indirect nature
of the PCI window.
2) If > 64MB of memory space is required, the IXP4xx can be
configured to use indirect registers to access the whole PCI
memory space. This currently allows for up to 1 GB (0x10000000
to 0x4FFFFFFF) of memory on the bus. The disadvantage of this
is that every PCI access requires three local register accesses
plus a spinlock, but in some cases the performance hit is
acceptable. In addition, you cannot mmap() PCI devices in this
case due to the indirect nature of the PCI window.
By default, the direct method is used. Choose this option if you
need to use the indirect method instead. If you don't know

6
arch/arm/mach-ixp4xx/common-pci.c
View File

@ -481,11 +481,7 @@ int ixp4xx_setup(int nr, struct pci_sys_data *sys)
res[1].name = "PCI Memory Space";
res[1].start = PCIBIOS_MIN_MEM;
#ifndef CONFIG_IXP4XX_INDIRECT_PCI
res[1].end = 0x4bffffff;
#else
res[1].end = 0x4fffffff;
#endif
res[1].end = PCIBIOS_MAX_MEM;
res[1].flags = IORESOURCE_MEM;
request_resource(&ioport_resource, &res[0]);

8
arch/arm/mach-ixp4xx/include/mach/hardware.h
View File

@ -18,7 +18,13 @@
#define __ASM_ARCH_HARDWARE_H__
#define PCIBIOS_MIN_IO 0x00001000
#define PCIBIOS_MIN_MEM (cpu_is_ixp43x() ? 0x40000000 : 0x48000000)
#ifdef CONFIG_IXP4XX_INDIRECT_PCI
#define PCIBIOS_MIN_MEM 0x10000000 /* 1 GB of indirect PCI MMIO space */
#define PCIBIOS_MAX_MEM 0x4FFFFFFF
#else
#define PCIBIOS_MIN_MEM 0x48000000 /* 64 MB of PCI MMIO space */
#define PCIBIOS_MAX_MEM 0x4BFFFFFF
#endif
/*
* We override the standard dma-mask routines for bouncing.

22
arch/arm/mach-ixp4xx/include/mach/io.h
View File

@ -26,22 +26,20 @@ extern int ixp4xx_pci_write(u32 addr, u32 cmd, u32 data);
/*
* IXP4xx provides two methods of accessing PCI memory space:
*
* 1) A direct mapped window from 0x48000000 to 0x4bffffff (64MB).
* 1) A direct mapped window from 0x48000000 to 0x4BFFFFFF (64MB).
* To access PCI via this space, we simply ioremap() the BAR
* into the kernel and we can use the standard read[bwl]/write[bwl]
* macros. This is the preffered method due to speed but it
* limits the system to just 64MB of PCI memory. This can be
* problamatic if using video cards and other memory-heavy
* targets.
*
* 2) If > 64MB of memory space is required, the IXP4xx can be configured
* to use indirect registers to access PCI (as we do below for I/O
* transactions). This allows for up to 128MB (0x48000000 to 0x4fffffff)
* of memory on the bus. The disadvantage of this is that every
* PCI access requires three local register accesses plus a spinlock,
* but in some cases the performance hit is acceptable. In addition,
* you cannot mmap() PCI devices in this case.
* limits the system to just 64MB of PCI memory. This can be
* problematic if using video cards and other memory-heavy targets.
*
* 2) If > 64MB of memory space is required, the IXP4xx can use indirect
* registers to access the whole 4 GB of PCI memory space (as we do below
* for I/O transactions). This allows currently for up to 1 GB (0x10000000
* to 0x4FFFFFFF) of memory on the bus. The disadvantage of this is that
* every PCI access requires three local register accesses plus a spinlock,
* but in some cases the performance hit is acceptable. In addition, you
* cannot mmap() PCI devices in this case.
*/
#ifndef CONFIG_IXP4XX_INDIRECT_PCI