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Commit 120fad72 authored by Alan Cox's avatar Alan Cox Committed by Andi Kleen
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[PATCH] i386: Fix Cyrix MediaGX detection 



The old Cyrix 5520 CPU detection code relied upon the PCI layer setup being
done earlier than the CPU setup, which is no longer true.  Fortunately we
know that if the processor is a MediaGX we can do type 1 pci config
accesses to check the companion chip.  We thus do those directly and from
this find the 5520 and implement the workarounds for the timer problem

Original report from takada@mbf.nifty.com, I sent a proposed patch which
Takara then corrected, tested and sent back to the list on 10th January.

Submitting for merging as it seems to have been missed

AK: Changed to use pci-direct.h and fix warning for !CONFIG_PCI (later
AK: originally from akpm)

Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: <takada@mbf.nifty.com>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7de6d361

arch/i386/kernel/cpu/cyrix.c

+11 −9
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <asm/io.h>

#include <asm/processor.h>

#include <asm/timer.h>

#include <asm/pci-direct.h>



#include "cpu.h"
@@ -183,14 +184,6 @@ static void __cpuinit geode_configure(void) 
}





#ifdef CONFIG_PCI

static struct pci_device_id __cpuinitdata cyrix_55x0[] = {

	{ PCI_DEVICE(PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5510) },

	{ PCI_DEVICE(PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5520) },

	{ },

};

#endif



static void __cpuinit init_cyrix(struct cpuinfo_x86 *c)

{

	unsigned char dir0, dir0_msn, dir0_lsn, dir1 = 0;
@@ -258,6 +251,8 @@ static void __cpuinit init_cyrix(struct cpuinfo_x86 *c) 


	case 4: /* MediaGX/GXm or Geode GXM/GXLV/GX1 */

#ifdef CONFIG_PCI

	{

		u32 vendor, device;

		/* It isn't really a PCI quirk directly, but the cure is the

		   same. The MediaGX has deep magic SMM stuff that handles the

		   SB emulation. It thows away the fifo on disable_dma() which
@@ -273,12 +268,19 @@ static void __cpuinit init_cyrix(struct cpuinfo_x86 *c) 
		printk(KERN_INFO "Working around Cyrix MediaGX virtual DMA bugs.\n");

		isa_dma_bridge_buggy = 2;



		/* We do this before the PCI layer is running. However we

		   are safe here as we know the bridge must be a Cyrix

		   companion and must be present */

		vendor = read_pci_config_16(0, 0, 0x12, PCI_VENDOR_ID);

		device = read_pci_config_16(0, 0, 0x12, PCI_DEVICE_ID);



		/*

		 *  The 5510/5520 companion chips have a funky PIT.

		 */  

		if (pci_dev_present(cyrix_55x0))

		if (vendor == PCI_VENDOR_ID_CYRIX &&

	 (device == PCI_DEVICE_ID_CYRIX_5510 || device == PCI_DEVICE_ID_CYRIX_5520))

			pit_latch_buggy = 1;

	}

#endif

		c->x86_cache_size=16;	/* Yep 16K integrated cache thats it */