[RFC PATCH 2/7] x86: introduce a set of platform feature flags

Pan, Jacob jun
2009-08-28T21:52:58Z

>From 8c587b87eef49660b498dd3728dab73a254b7ea9 Mon Sep 17 00:00:00 2001
From: Jacob Pan <jacob.jun.pan@intel.com>
Date: Thu, 11 Jun 2009 09:37:26 -0700
Subject: [PATCH] x86: introduce a set of platform feature flags

This patch introduces a set of x86 pc platform feature flags. the intention is
to clean up setup code based on the availability of patform features.

With the introduction of non-PC x86 platforms, these flags will also pave
the way for cleaner integration.

The current feature flags are not a complete set of all possible PC features
only the ones relavent to system setup, such as resource allocation, are
included.

Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
---
arch/x86/Kconfig | 13 +++-
arch/x86/include/asm/platform_feature.h | 68 +++++++++++++++++++
arch/x86/kernel/.gitignore | 1 +
arch/x86/kernel/Makefile | 11 +++
arch/x86/kernel/mkx86pcflags.pl | 32 +++++++++
arch/x86/kernel/platform_info.c | 112 +++++++++++++++++++++++++++++++
6 files changed, 236 insertions(+), 1 deletions(-)
create mode 100644 arch/x86/include/asm/platform_feature.h
create mode 100644 arch/x86/kernel/mkx86pcflags.pl
create mode 100644 arch/x86/kernel/platform_info.c

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 13ffa5d..7990f6c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1658,7 +1658,18 @@ config CMDLINE_OVERRIDE

This is used to work around broken boot loaders. This should
be set to 'N' under normal conditions.
-
+config MRST
+ bool "Moorestown MID platform"
+ default n
+ depends on X86_32
+ select SFI
+ help
+ Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
+ Internet Device(MID) platform. Moorestown consists of two chips:
+ Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
+ Unlike standard x86 PCs, Moorestown does not have many legacy devices
+ nor standard legacy replacement devices/features. e.g. Moorestown does
+ not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
endmenu

config ARCH_ENABLE_MEMORY_HOTPLUG
diff --git a/arch/x86/include/asm/platform_feature.h b/arch/x86/include/asm/platform_feature.h
new file mode 100644
index 0000000..fcf9907
--- /dev/null
+++ b/arch/x86/include/asm/platform_feature.h
@@ -0,0 +1,68 @@
+/*
+ * platform_feature.h - Defines x86 platform feature bits
+ *
+ * (C) Copyright 2008 Intel Corporation
+ * Author: Jacob Pan (jacob.jun.pan@intel.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ *
+ * Note: platform feature flags allow kernel to identify hardware capabilities
+ * at boottime and runtime. It enables binary compaitiblity between standard
+ * X86 PC and non-standard X86 platforms such as MID. These flags are default
+ * to X86 PC standard, at boot time, they will be overwritten by system tables
+ * provided by firmware.
+ *
+ */
+#ifndef _ASM_X86_PLATFORM_FEATURE_H
+#define _ASM_X86_PLATFORM_FEATURE_H
+
+#ifndef __ASSEMBLY__
+#include <linux/bitops.h>
+#endif
+#include <asm/required-features.h>
+
+#define N_PLATFORM_CAPINTS 2 /* N 32-bit words worth of info */
+/* X86 base platform features, include PC, legacy free MID devices, etc.
+ * This list provides early and important information to the kernel in a
+ * centralized place such that kernel can make a decision on the best
+ * choice of which system devices to use. e.g. timers or interrupt
+ * controllers.
+ */
+#define X86_PLATFORM_FEATURE_8259 (0*32+0) /* i8259A PIC */
+#define X86_PLATFORM_FEATURE_8254 (0*32+1) /* i8253/4 PIT */
+#define X86_PLATFORM_FEATURE_IOAPIC (0*32+2) /* IO-APIC */
+#define X86_PLATFORM_FEATURE_HPET (0*32+3) /* HPET timer */
+#define X86_PLATFORM_FEATURE_RTC (0*32+4) /* real time clock*/
+#define X86_PLATFORM_FEATURE_FLOPPY (0*32+5) /* ISA floppy */
+#define X86_PLATFORM_FEATURE_ISA (0*32+6) /* ISA/LPC bus */
+#define X86_PLATFORM_FEATURE_BIOS (0*32+7) /* BIOS service,
+ * e.g. int calls
+ * EBDA, etc.
+ */
+#define X86_PLATFORM_FEATURE_ACPI (0*32+8) /* has ACPI support */
+#define X86_PLATFORM_FEATURE_SFI (0*32+9) /* has SFI support */
+#define X86_PLATFORM_FEATURE_8042 (0*32+10) /* i8042 KBC */
+#define X86_PLATFORM_FEATURE_APBT (0*32+11) /* APB timer */
+#define X86_PLATFORM_FEATURE_VRTC (0*32+12) /* virtual RTC */
+#define X86_PLATFORM_FEATURE_PCISHIM (0*32+13) /* fake PCI MCFG */
+
+extern __u32 platform_feature[N_PLATFORM_CAPINTS];
+extern const char *const
+ x86_platform_available_feature[N_PLATFORM_CAPINTS * 32];
+#define platform_has(bit) \
+ test_bit(bit, (unsigned long *)platform_feature)
+
+#define platform_feature_set_flag(bit) \
+ __set_bit(bit, (unsigned long *)platform_feature)
+
+#define clear_platform_feature(bit) \
+ __clear_bit(bit, (unsigned long *)platform_feature)
+
+void platform_feature_init_default(void);
+void clear_all_platform_feature(void);
+
+
+#endif /* _ASM_X86_PLATFORM_FEATURE_H */
diff --git a/arch/x86/kernel/.gitignore b/arch/x86/kernel/.gitignore
index 08f4fd7..0943d5e 100644
--- a/arch/x86/kernel/.gitignore
+++ b/arch/x86/kernel/.gitignore
@@ -1,3 +1,4 @@
vsyscall.lds
vsyscall_32.lds
vmlinux.lds
+x86pcflags.c
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 5929855..7aed450 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_IA32_EMULATION) += tls.o
obj-y += step.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += cpu/
+obj-y += platform_info.o x86pcflags.o
obj-y += acpi/
obj-y += reboot.o
obj-$(CONFIG_MCA) += mca_32.o
@@ -114,6 +115,16 @@ obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o

obj-$(CONFIG_SWIOTLB) += pci-swiotlb.o

+quiet_cmd_mkx86pcflags = MKFEATURE $@
+ cmd_mkx86pcflags = $(PERL) $(srctree)/$(src)/mkx86pcflags.pl $< $@
+
+platform_feature = $(src)/../include/asm/platform_feature.h
+
+
+targets += x86pcflags.c
+$(obj)/x86pcflags.c: $(platform_feature) $(src)/mkx86pcflags.pl FORCE
+ $(call if_changed,mkx86pcflags)
+
###
# 64 bit specific files
ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/mkx86pcflags.pl b/arch/x86/kernel/mkx86pcflags.pl
new file mode 100644
index 0000000..19c13aa
--- /dev/null
+++ b/arch/x86/kernel/mkx86pcflags.pl
@@ -0,0 +1,32 @@
+#!/usr/bin/perl
+#
+# Generate the x86_platform_available_feature[] array from arch/x86/include/asm/platform_feature.h
+#
+
+($in, $out) = @ARGV;
+
+open(IN, "< $in\0") or die "$0: cannot open: $in: $!\n";
+open(OUT, "> $out\0") or die "$0: cannot create: $out: $!\n";
+
+print OUT "#include <asm/platform_feature.h>\n\n";
+print OUT "const char * const x86_platform_available_feature[N_PLATFORM_CAPINTS*32] = {\n";
+
+while (defined($line = <IN>)) {
+ if ($line =~ /^\s*\#\s*define\s+(X86_PLATFORM_FEATURE_(\S+))\s+(.*)$/) {
+ $macro = $1;
+ $feature = $2;
+ $tail = $3;
+ if ($tail =~ /\/\*\s*\"([^"]*)\".*\*\//) {
+ $feature = $1;
+ }
+
+ if ($feature ne '') {
+ printf OUT "\t%-32s = \"%s\",\n",
+ "[$macro]", "\L$feature";
+ }
+ }
+}
+print OUT "};\n";
+
+close(IN);
+close(OUT);
diff --git a/arch/x86/kernel/platform_info.c b/arch/x86/kernel/platform_info.c
new file mode 100644
index 0000000..63cee8f
--- /dev/null
+++ b/arch/x86/kernel/platform_info.c
@@ -0,0 +1,112 @@
+#include <linux/smp.h>
+#include <linux/timex.h>
+#include <linux/string.h>
+#include <linux/seq_file.h>
+#include <linux/sysdev.h>
+#include <linux/cpu.h>
+
+#include <asm/bootparam.h>
+#include <asm/platform_feature.h>
+#include <asm/setup.h>
+#include <asm/bios_ebda.h>
+
+/*
+ * Set of default platform features of standard X86 PC. May be overwritten by
+ * information found during boot, such as boot parameters, SFI, ACPI tables,
+ * etc. Not every X86PC feature is listed here, only include useful ones that
+ * can not be safely detected at runtime.
+ */
+__u32 platform_feature[N_PLATFORM_CAPINTS] =
+{
+ (1UL << X86_PLATFORM_FEATURE_8259) |
+ (1UL << X86_PLATFORM_FEATURE_8042) |
+ (1UL << X86_PLATFORM_FEATURE_IOAPIC) |
+ (1UL << X86_PLATFORM_FEATURE_BIOS) |
+ (1UL << X86_PLATFORM_FEATURE_HPET) |
+ (1UL << X86_PLATFORM_FEATURE_8254) |
+ (1UL << X86_PLATFORM_FEATURE_RTC) |
+ (1UL << X86_PLATFORM_FEATURE_ISA) |
+ (1UL << X86_PLATFORM_FEATURE_FLOPPY),
+ 0
+};
+EXPORT_SYMBOL_GPL(platform_feature);
+
+inline void clear_all_platform_feature(void)
+{
+ memset(platform_feature, 0, sizeof(platform_feature));
+}
+
+static ssize_t
+sysfs_show_available_platform_feature(struct sys_device *dev,
+ struct sysdev_attribute *attr, char *buf)
+{
+ ssize_t count = 0;
+ int i;
+
+ for (i = 0; i < 32*N_PLATFORM_CAPINTS; i++) {
+ if (x86_platform_available_feature[i] != NULL) {
+ count += snprintf(buf + count,
+ max((ssize_t)PAGE_SIZE - count,
+ (ssize_t)0), "%s ",
+ x86_platform_available_feature[i]);
+ }
+ }
+ count += snprintf(buf + count,
+ max((ssize_t)PAGE_SIZE - count, (ssize_t)0), "\n");
+
+ return count;
+}
+
+static ssize_t
+sysfs_show_current_platform_feature(struct sys_device *dev,
+ struct sysdev_attribute *attr,
+ char *buf)
+{
+ ssize_t count = 0;
+ int i;
+
+ for (i = 0; i < 32*N_PLATFORM_CAPINTS; i++) {
+ if (platform_has(i))
+ count += snprintf(buf + count,
+ max((ssize_t)PAGE_SIZE - count, (ssize_t)0),
+ "%s ", x86_platform_available_feature[i]);
+ }
+ count += snprintf(buf + count,
+ max((ssize_t)PAGE_SIZE - count, (ssize_t)0), "\n");
+
+ return count;
+}
+
+static SYSDEV_ATTR(current_platform_feature, 0444,
+ sysfs_show_current_platform_feature,
+ NULL);
+
+static SYSDEV_ATTR(available_platform_feature, 0444,
+ sysfs_show_available_platform_feature, NULL);
+
+static struct sysdev_class platform_feature_sysclass = {
+ .name = "platform_feature",
+};
+
+static struct sys_device device_platform_feature = {
+ .id = 0,
+ .cls = &platform_feature_sysclass,
+};
+
+static int __init sysfs_platforminfo_init(void)
+{
+ int error = sysdev_class_register(&platform_feature_sysclass);
+
+ if (!error)
+ error = sysdev_register(&device_platform_feature);
+ if (!error)
+ error = sysdev_create_file(
+ &device_platform_feature,
+ &attr_current_platform_feature);
+ if (!error)
+ error = sysdev_create_file(
+ &device_platform_feature,
+ &attr_available_platform_feature);
+ return error;
+}
+arch_initcall(sysfs_platforminfo_init);
--
1.5.6.5