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[ARM] Introduce new bitmask based cache type macros

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Rather than trying to (inaccurately) decode the cache type from the
registers each time we need to decide what type of cache we have,
use a bitmask initialized early during boot.

Since the setup is a one-off initialization, we can be a little more
clever and take account of the CPU architecture as well.

Note that we continue to achieve the compactness on optimised kernels
by forcing tests to always-false or always-true as appropriate, thereby
allowing the compiler to do build-time code elimination.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King
2008-09-25 15:35:28 +01:00
committed by Russell King
parent 90f1e08478
commit c0e9587841
2 changed files with 60 additions and 82 deletions
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22
arch/arm/kernel/setup.c
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@@ -67,6 +67,8 @@ unsigned int processor_id;
EXPORT_SYMBOL(processor_id);
unsigned int __machine_arch_type;
EXPORT_SYMBOL(__machine_arch_type);
unsigned int cacheid;
EXPORT_SYMBOL(cacheid);
unsigned int __atags_pointer __initdata;
@@ -229,6 +231,25 @@ int cpu_architecture(void)
return cpu_arch;
}
static void __init cacheid_init(void)
{
unsigned int cachetype = read_cpuid_cachetype();
unsigned int arch = cpu_architecture();
if (arch >= CPU_ARCH_ARMv7) {
cacheid = CACHEID_VIPT_NONALIASING;
if ((cachetype & (3 << 14)) == 1 << 14)
cacheid |= CACHEID_ASID_TAGGED;
} else if (arch >= CPU_ARCH_ARMv6) {
if (cachetype & (1 << 23))
cacheid = CACHEID_VIPT_ALIASING;
else
cacheid = CACHEID_VIPT_NONALIASING;
} else {
cacheid = CACHEID_VIVT;
}
}
/*
* These functions re-use the assembly code in head.S, which
* already provide the required functionality.
@@ -278,6 +299,7 @@ static void __init setup_processor(void)
elf_hwcap &= ~HWCAP_THUMB;
#endif
cacheid_init();
cpu_proc_init();
}