port arch/x86/kernel/probe_roms_32.c for use in 'platform' support

This provides at least a kernel bug compatible method of scanning for an
adapter-rom.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 279 insertions, 0 deletions

diff --git a/probe_roms.c b/probe_roms.c
new file mode 100644
index 00000000..06ec3f5a
--- /dev/null
+++ b/probe_roms.c
@@ -0,0 +1,279 @@
+/*
+ * probe_roms - scan for Adapter ROMS
+ *
+ * (based on linux-2.6:arch/x86/kernel/probe_roms_32.c)
+ *
+ * Copyright (C) 2008 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "probe_roms.h"
+#include <unistd.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <asm/types.h>
+
+static void *rom_mem = MAP_FAILED;
+static int rom_fd = -1;
+const static int rom_len = 0xf0000 - 0xc0000; /* option-rom memory region */
+static int _sigbus;
+#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
+
+static void sigbus(int sig)
+{
+	_sigbus = 1;
+}
+
+static int probe_address8(const __u8 *ptr, __u8 *val)
+{
+	int rc = 0;
+
+	*val = *ptr;
+	if (_sigbus)
+		rc = -1;
+	_sigbus = 0;
+
+	return rc;
+}
+
+static int probe_address16(const __u16 *ptr, __u16 *val)
+{
+	int rc = 0;
+
+	*val = *ptr;
+	if (_sigbus)
+		rc = -1;
+	_sigbus = 0;
+
+	return rc;
+}
+
+void probe_roms_exit(void)
+{
+	signal(SIGBUS, SIG_DFL);
+	if (rom_fd >= 0) {
+		close(rom_fd);
+		rom_fd = -1;
+	}
+	if (rom_mem != MAP_FAILED) {
+		munmap(rom_mem, rom_len);
+		rom_mem = MAP_FAILED;
+	}
+}
+
+int probe_roms_init(void)
+{
+	int fd;
+	int rc = 0;
+
+	if (signal(SIGBUS, sigbus) == SIG_ERR)
+		rc = -1;
+	if (rc == 0) {
+		fd = open("/dev/mem", O_RDONLY);
+		if (fd < 0)
+			rc = -1;
+	}
+	if (rc == 0) {
+		rom_mem = mmap(NULL, rom_len, PROT_READ, MAP_PRIVATE, fd, 0xc0000);
+		if (rom_mem == MAP_FAILED)
+			rc = -1;
+	}
+
+	if (rc == 0)
+		rom_fd = fd;
+	else
+		probe_roms_exit();
+
+	return rc;
+}
+
+/**
+ * isa_bus_to_virt - convert physical address to mmap'd region
+ * @addr - address to convert
+ *
+ * Only valid between a successful call to probe_roms_init and the
+ * corresponding probe_roms_exit
+ */
+static void *isa_bus_to_virt(unsigned long addr)
+{
+	return rom_mem + (addr - 0xc0000);
+}
+
+struct resource {
+	unsigned long start;
+	unsigned long end;
+	const char *name;
+};
+
+static struct resource system_rom_resource = {
+	.name	= "System ROM",
+	.start	= 0xf0000,
+	.end	= 0xfffff,
+};
+
+static struct resource extension_rom_resource = {
+	.name	= "Extension ROM",
+	.start	= 0xe0000,
+	.end	= 0xeffff,
+};
+
+static struct resource adapter_rom_resources[] = { {
+	.name 	= "Adapter ROM",
+	.start	= 0xc8000,
+	.end	= 0,
+}, {
+	.name 	= "Adapter ROM",
+	.start	= 0,
+	.end	= 0,
+}, {
+	.name 	= "Adapter ROM",
+	.start	= 0,
+	.end	= 0,
+}, {
+	.name 	= "Adapter ROM",
+	.start	= 0,
+	.end	= 0,
+}, {
+	.name 	= "Adapter ROM",
+	.start	= 0,
+	.end	= 0,
+}, {
+	.name 	= "Adapter ROM",
+	.start	= 0,
+	.end	= 0,
+} };
+
+static struct resource video_rom_resource = {
+	.name 	= "Video ROM",
+	.start	= 0xc0000,
+	.end	= 0xc7fff,
+};
+
+#define ROMSIGNATURE 0xaa55
+
+static int romsignature(const unsigned char *rom)
+{
+	const unsigned short * const ptr = (const unsigned short *)rom;
+	unsigned short sig = 0;
+
+	return probe_address16(ptr, &sig) == 0 && sig == ROMSIGNATURE;
+}
+
+static int romchecksum(const unsigned char *rom, unsigned long length)
+{
+	unsigned char sum, c;
+
+	for (sum = 0; length && probe_address8(rom++, &c) == 0; length--)
+		sum += c;
+	return !length && !sum;
+}
+
+int scan_adapter_roms(scan_fn fn)
+{
+	/* let scan_fn examing each of the adapter roms found by probe_roms */
+	int i;
+	int found;
+
+	if (rom_fd < 0)
+		return 0;
+
+	found = 0;
+	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources); i++) {
+		struct resource *res = &adapter_rom_resources[i];
+
+		if (res->start) {
+			found = fn(isa_bus_to_virt(res->start),
+				   isa_bus_to_virt(res->end));
+			if (found)
+				break;
+		} else
+			break;
+	}
+
+	return found;
+}
+
+void probe_roms(void)
+{
+	const void *rom;
+	unsigned long start, length, upper;
+	unsigned char c;
+	int i;
+
+	if (rom_fd < 0)
+		return;
+
+	/* video rom */
+	upper = adapter_rom_resources[0].start;
+	for (start = video_rom_resource.start; start < upper; start += 2048) {
+		rom = isa_bus_to_virt(start);
+		if (!romsignature(rom))
+			continue;
+
+		video_rom_resource.start = start;
+
+		if (probe_address8(rom + 2, &c) != 0)
+			continue;
+
+		/* 0 < length <= 0x7f * 512, historically */
+		length = c * 512;
+
+		/* if checksum okay, trust length byte */
+		if (length && romchecksum(rom, length))
+			video_rom_resource.end = start + length - 1;
+		break;
+	}
+
+	start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
+	if (start < upper)
+		start = upper;
+
+	/* system rom */
+	upper = system_rom_resource.start;
+
+	/* check for extension rom (ignore length byte!) */
+	rom = isa_bus_to_virt(extension_rom_resource.start);
+	if (romsignature(rom)) {
+		length = extension_rom_resource.end - extension_rom_resource.start + 1;
+		if (romchecksum(rom, length))
+			upper = extension_rom_resource.start;
+	}
+
+	/* check for adapter roms on 2k boundaries */
+	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
+		rom = isa_bus_to_virt(start);
+		if (!romsignature(rom))
+			continue;
+
+		if (probe_address8(rom + 2, &c) != 0)
+			continue;
+
+		/* 0 < length <= 0x7f * 512, historically */
+		length = c * 512;
+
+		/* but accept any length that fits if checksum okay */
+		if (!length || start + length > upper || !romchecksum(rom, length))
+			continue;
+
+		adapter_rom_resources[i].start = start;
+		adapter_rom_resources[i].end = start + length - 1;
+
+		start = adapter_rom_resources[i++].end & ~2047UL;
+	}
+}
+