Re: [PATCH] x86: CPU detection for RDC System-on-Chip

From: Florian Fainelli
Date: Sun May 16 2010 - 09:21:59 EST

Le dimanche 16 mai 2010 15:19:17, Alan Cox a écrit :
> > + 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@xxxxxxxxxxxxxxx\n",
> > + customer_id);
>
> Surely this should be a break as you want to set the vendor. You've
> established its an RDC at this point have you not - so you want to set
> x86_vendor.

Right, please find updated version below.
--
From: Mark Kelly <mark@xxxxxxxxxxxx>

The RDC System-on-Chip i486 compatible core does not support the cpuid
instruction and specific detection logic is required for this chip. The patch
below adds proper vendor and SoC type detection.

Signed-off-by: Mark Kelly <mark@xxxxxxxxxxxx>
Tested-by: Florian Fainelli <florian@xxxxxxxxxxx>
---
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@xxxxxxxxxxxx
+
+
+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@xxxxxxxxxxxx 2009
+
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 39e8e10..21b02f2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -419,6 +419,7 @@ 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 5a51379..eddf979 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 3a785da..af2d4a6 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -25,6 +25,7 @@ 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_EVENTS) += perf_event.o

diff --git a/arch/x86/kernel/cpu/rdc.c b/arch/x86/kernel/cpu/rdc.c
new file mode 100644
index 0000000..909c2b5
--- /dev/null
+++ b/arch/x86/kernel/cpu/rdc.c
@@ -0,0 +1,71 @@
+/*
+ * See Documentation/x86/rdc.txt
+ *
+ * mark@xxxxxxxxxxxx
+ */
+
+#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@xxxxxxxxxxxxxxx\n",
+ customer_id);
+ break;
+ }
+
+ 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);
--
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