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MIPS: Set default pci cache line size.

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On MIPS the generic PCI code has always defaulted to L1_CACHE_BYTES
because the architecutre PCI code did not provide a better default.
In particular on systems with S-caches or T-caches this was suboptimal.

Provide a better default by setting pci_dfl_cache_line_size based on
the size of the line size of the lowest level of the cache hierarchy.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/2982/
This commit is contained in:
Ralf Baechle 2012-01-11 15:37:16 +01:00
parent f467e4bfb5
commit c539ef7d35
1 changed files with 28 additions and 1 deletions
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29
arch/mips/pci/pci.c
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@ -4,8 +4,11 @@
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* Copyright (C) 2003, 04 Ralf Baechle (ralf@linux-mips.org)
* Copyright (C) 2003, 04, 11 Ralf Baechle (ralf@linux-mips.org)
* Copyright (C) 2011 Wind River Systems,
* written by Ralf Baechle (ralf@linux-mips.org)
*/
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
@ -14,6 +17,8 @@
#include <linux/types.h>
#include <linux/pci.h>
#include <asm/cpu-info.h>
/*
* Indicate whether we respect the PCI setup left by the firmware.
*
@ -150,10 +155,32 @@ out:
"Skipping PCI bus scan due to resource conflict\n");
}
static void __init pcibios_set_cache_line_size(void)
{
struct cpuinfo_mips *c = &current_cpu_data;
unsigned int lsize;
/*
* Set PCI cacheline size to that of the highest level in the
* cache hierarchy.
*/
lsize = c->dcache.linesz;
lsize = c->scache.linesz ? : lsize;
lsize = c->tcache.linesz ? : lsize;
BUG_ON(!lsize);
pci_dfl_cache_line_size = lsize >> 2;
pr_debug("PCI: pci_cache_line_size set to %d bytes\n", lsize);
}
static int __init pcibios_init(void)
{
struct pci_controller *hose;
pcibios_set_cache_line_size();
/* Scan all of the recorded PCI controllers. */
for (hose = hose_head; hose; hose = hose->next)
pcibios_scanbus(hose);