qemu: Initial support for the qemu firmware config interface.

qemu has a special device to pass configuration information
from qemu to the firmware.  This patch adds initial support
the interface, namely some infrastructure, detection code and
a function to query the number of CPUs.

Change-Id: I43ff5f4fbf12334a91422aa38f514a82a1d5219e
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-on: http://review.coreboot.org/3343
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/mainboard/emulation/qemu-x86/Makefile.inc

@@ -1,2 +1,3 @@
 cpu_incs += $(src)/mainboard/emulation/qemu-x86/cache_as_ram.inc
 ramstage-y += northbridge.c
+ramstage-y += fw_cfg.c

src/mainboard/emulation/qemu-x86/fw_cfg.c

@@ -0,0 +1,59 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that 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 <string.h>
+#include <console/console.h>
+#include <arch/io.h>
+
+#include "fw_cfg.h"
+#include "fw_cfg_if.h"
+
+#define FW_CFG_PORT_CTL       0x0510
+#define FW_CFG_PORT_DATA      0x0511
+
+static unsigned char fw_cfg_detected = 0xff;
+
+static int fw_cfg_present(void)
+{
+	static const char qsig[] = "QEMU";
+	unsigned char sig[4];
+
+	if (fw_cfg_detected == 0xff) {
+		fw_cfg_get(FW_CFG_SIGNATURE, sig, sizeof(sig));
+		fw_cfg_detected = (memcmp(sig, qsig, 4) == 0) ? 1 : 0;
+		printk(BIOS_INFO, "QEMU: firmware config interface %s\n",
+		       fw_cfg_detected ? "detected" : "not found");
+	}
+	return fw_cfg_detected;
+}
+
+void fw_cfg_get(int entry, void *dst, int dstlen)
+{
+	outw(entry, FW_CFG_PORT_CTL);
+	insb(FW_CFG_PORT_DATA, dst, dstlen);
+}
+
+int fw_cfg_max_cpus(void)
+{
+	unsigned short max_cpus;
+
+	if (!fw_cfg_present())
+		return -1;
+
+	fw_cfg_get(FW_CFG_MAX_CPUS, &max_cpus, sizeof(max_cpus));
+	return max_cpus;
+}

src/mainboard/emulation/qemu-x86/fw_cfg.h

@@ -0,0 +1,19 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that 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
+ */
+
+void fw_cfg_get(int entry, void *dst, int dstlen);
+int fw_cfg_max_cpus(void);

src/mainboard/emulation/qemu-x86/fw_cfg_if.h

@@ -0,0 +1,53 @@
+/*
+ * This are the qemu firmware config interface defines and structs.
+ * Copyed over from qemu soure tree, include/hw/nvram/fw_cfg.h
+ */
+
+#define FW_CFG_SIGNATURE        0x00
+#define FW_CFG_ID               0x01
+#define FW_CFG_UUID             0x02
+#define FW_CFG_RAM_SIZE         0x03
+#define FW_CFG_NOGRAPHIC        0x04
+#define FW_CFG_NB_CPUS          0x05
+#define FW_CFG_MACHINE_ID       0x06
+#define FW_CFG_KERNEL_ADDR      0x07
+#define FW_CFG_KERNEL_SIZE      0x08
+#define FW_CFG_KERNEL_CMDLINE   0x09
+#define FW_CFG_INITRD_ADDR      0x0a
+#define FW_CFG_INITRD_SIZE      0x0b
+#define FW_CFG_BOOT_DEVICE      0x0c
+#define FW_CFG_NUMA             0x0d
+#define FW_CFG_BOOT_MENU        0x0e
+#define FW_CFG_MAX_CPUS         0x0f
+#define FW_CFG_KERNEL_ENTRY     0x10
+#define FW_CFG_KERNEL_DATA      0x11
+#define FW_CFG_INITRD_DATA      0x12
+#define FW_CFG_CMDLINE_ADDR     0x13
+#define FW_CFG_CMDLINE_SIZE     0x14
+#define FW_CFG_CMDLINE_DATA     0x15
+#define FW_CFG_SETUP_ADDR       0x16
+#define FW_CFG_SETUP_SIZE       0x17
+#define FW_CFG_SETUP_DATA       0x18
+#define FW_CFG_FILE_DIR         0x19
+
+#define FW_CFG_FILE_FIRST       0x20
+#define FW_CFG_FILE_SLOTS       0x10
+#define FW_CFG_MAX_ENTRY        (FW_CFG_FILE_FIRST+FW_CFG_FILE_SLOTS)
+
+#define FW_CFG_WRITE_CHANNEL    0x4000
+#define FW_CFG_ARCH_LOCAL       0x8000
+#define FW_CFG_ENTRY_MASK       ~(FW_CFG_WRITE_CHANNEL | FW_CFG_ARCH_LOCAL)
+
+#define FW_CFG_INVALID          0xffff
+
+typedef struct FWCfgFile {
+    uint32_t  size;        /* file size */
+    uint16_t  select;      /* write this to 0x510 to read it */
+    uint16_t  reserved;
+    char      name[56];
+} FWCfgFile;
+
+typedef struct FWCfgFiles {
+    uint32_t  count;
+    FWCfgFile f[];
+} FWCfgFiles;