lkml.org 
[lkml]   [2009]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[patch, v2] x86: CPU detection for RDC

    On Mon, 17 Aug 2009, H. Peter Anvin wrote:

    > On 08/17/2009 02:31 PM, Andi Kleen wrote:
    > >
    > > I thought it was to prevent oopses for zero cpu according
    > > to the reporter?
    > >
    > > But these oopses should be probably separately fixed anyways.
    > >
    >
    > They should.

    Perhaps, but they don't need to be. Unfortunately I was testing up to
    2.6.30.5 (which gives the Oops), but someone must have changed the
    detection code for 486 in Linus' tree, because when I tried that (at
    Ingo's suggestion) I magically got a boot, and a correctly recognised
    486 without my patch. This does rather remove my reason for the patch
    submission, but I will carry on if people think this is still worthwhile.

    With the above in mind we can give up on detection without fear of a
    subsequent Oops, so I've simplified the code to not bother with
    the unrecognised variants (still gives a warning).

    I've added the PCI config dependency, and the runtime check. I'll call
    this v2, please ignore all the previous patches. It's against
    2.6.31-rc6-tip.

    regards,
    Mark.



    Signed-off-by: Mark Kelly <mark@bifferos.com>
    diff --git a/Documentation/x86/rdc.txt b/Documentation/x86/rdc.txt
    new file mode 100644
    index 0000000..f9591af
    --- /dev/null
    +++ b/Documentation/x86/rdc.txt
    @@ -0,0 +1,69 @@
    +
    +Introduction
    +============
    +
    +RDC (http://www.rdc.com.tw) have been manufacturing x86-compatible SoC
    +(system-on-chips) for a number of years. They are not the fastest of
    +CPUs (clock speeds ranging from 133-150MHz) but 486SX compatibility
    +coupled with very low power consumption[1] and low cost make them ideal
    +for embedded applications.
    +
    +
    +Where to find
    +=============
    +
    +RDC chips show up in numerous embedded devices, but be careful since
    +many of them will not run Linux 2.6 without significant expertise.
    +
    +There are several variants of what the linux kernel refers to generically
    +as RDC321X: R8610, R321x, S3282 and AMRISC20000.
    +
    +R321x: Found in various routers, see the OpenWrt project for details,
    + http://wiki.openwrt.org/oldwiki/rdcport
    +
    +R8610: Found on the RDC evaluation board
    + http://www.ivankuten.com/system-on-chip-soc/rdc-r8610/
    +
    +AMRISC20000: Found in the MGB-100 wireless hard disk
    + http://tintuc.no-ip.com/linux/tipps/mgb100/
    +
    +S3282: Found in various NAS devices, including the Bifferboard
    + http://www.bifferos.com
    +
    +
    +Kernel Configuration
    +====================
    +
    +Add support for this CPU with CONFIG_X86_RDC321X. Ensure that maths
    +emulation is included (CONFIG_MATH_EMULATION selected) and avoid MCE
    +(CONFIG_X86_MCE not selected).
    +
    +
    +CPU detection
    +=============
    +
    +None of these chips support the cpuid instruction, so as with some
    +other x86 compatible SoCs, we must check the north bridge and look
    +for specific 'signature' PCI device config.
    +
    +The current detection code has been tested only on the Bifferboard
    +(S3282 CPU), please send bug reports or success stories with
    +other devices to bifferos@yahoo.co.uk.
    +
    +
    +Credits
    +=======
    +
    +Many thanks to RDC for providing the customer codes to allow
    +detection of all known variants, without which this detection code
    +would have been very hard to ascertain.
    +
    +
    +References
    +==========
    +
    +[1] S3282 in certain NAS solutions consumes less than 1W
    +
    +
    +mark@bifferos.com 2009
    +
    diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
    index 1655b77..5d2bcaa 100644
    --- a/arch/x86/Kconfig
    +++ b/arch/x86/Kconfig
    @@ -382,6 +382,7 @@ config X86_RDC321X
    bool "RDC R-321x SoC"
    depends on X86_32
    depends on X86_EXTENDED_PLATFORM
    + select PCI
    select M486
    select X86_REBOOTFIXUPS
    ---help---
    diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
    index 2b03f70..75b96e9 100644
    --- a/arch/x86/include/asm/processor.h
    +++ b/arch/x86/include/asm/processor.h
    @@ -122,7 +122,8 @@ struct cpuinfo_x86 {
    #define X86_VENDOR_CENTAUR 5
    #define X86_VENDOR_TRANSMETA 7
    #define X86_VENDOR_NSC 8
    -#define X86_VENDOR_NUM 9
    +#define X86_VENDOR_RDC 9
    +#define X86_VENDOR_NUM 10

    #define X86_VENDOR_UNKNOWN 0xff

    diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
    index 3efcb2b..55ba09a 100644
    --- a/arch/x86/kernel/cpu/Makefile
    +++ b/arch/x86/kernel/cpu/Makefile
    @@ -22,6 +22,7 @@ obj-$(CONFIG_CPU_SUP_CYRIX_32) += cyrix.o
    obj-$(CONFIG_CPU_SUP_CENTAUR) += centaur.o
    obj-$(CONFIG_CPU_SUP_TRANSMETA_32) += transmeta.o
    obj-$(CONFIG_CPU_SUP_UMC_32) += umc.o
    +obj-$(CONFIG_X86_RDC321X) += rdc.o

    obj-$(CONFIG_PERF_COUNTERS) += perf_counter.o

    diff --git a/arch/x86/kernel/cpu/rdc.c b/arch/x86/kernel/cpu/rdc.c
    new file mode 100644
    index 0000000..369a671
    --- /dev/null
    +++ b/arch/x86/kernel/cpu/rdc.c
    @@ -0,0 +1,69 @@
    +/*
    + * See Documentation/x86/rdc.txt
    + *
    + * mark@bifferos.com
    + */
    +
    +#include <linux/pci.h>
    +#include <asm/pci-direct.h>
    +#include "cpu.h"
    +
    +
    +static void __cpuinit rdc_identify(struct cpuinfo_x86 *c)
    +{
    + u16 vendor, device;
    + u32 customer_id;
    +
    + if (!early_pci_allowed())
    + return;
    +
    + /* RDC CPU is SoC (system-on-chip), Northbridge is always present */
    + vendor = read_pci_config_16(0, 0, 0, PCI_VENDOR_ID);
    + device = read_pci_config_16(0, 0, 0, PCI_DEVICE_ID);
    +
    + if (vendor != PCI_VENDOR_ID_RDC || device != PCI_DEVICE_ID_RDC_R6020)
    + return; /* not RDC */
    + /*
    + * NB: We could go on and check other devices, e.g. r6040 NIC, but
    + * that's probably overkill
    + */
    +
    + customer_id = read_pci_config(0, 0, 0, 0x90);
    +
    + switch (customer_id) {
    + /* id names are from RDC */
    + case 0x00321000:
    + strcpy(c->x86_model_id, "R3210/R3211");
    + break;
    + case 0x00321001:
    + strcpy(c->x86_model_id, "AMITRISC20000/20010");
    + break;
    + case 0x00321002:
    + strcpy(c->x86_model_id, "R3210X/Edimax");
    + break;
    + case 0x00321003:
    + strcpy(c->x86_model_id, "R3210/Kcodes");
    + break;
    + case 0x00321004: /* tested */
    + strcpy(c->x86_model_id, "S3282/CodeTek");
    + break;
    + case 0x00321007:
    + strcpy(c->x86_model_id, "R8610");
    + break;
    + default:
    + pr_info("RDC CPU: Unrecognised Customer ID (0x%x) please report to linux-kernel@vger.kernel.org\n", customer_id);
    + return;
    + }
    +
    + strcpy(c->x86_vendor_id, "RDC");
    + c->x86_vendor = X86_VENDOR_RDC;
    +}
    +
    +static const struct cpu_dev __cpuinitconst rdc_cpu_dev = {
    + .c_vendor = "RDC",
    + .c_ident = { "RDC" },
    + .c_identify = rdc_identify,
    + .c_x86_vendor = X86_VENDOR_RDC,
    +};
    +
    +cpu_dev_register(rdc_cpu_dev);

    \
     
     \ /
      Last update: 2009-08-18 00:39    [W:0.088 / U:0.020 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site