1 files changed, 92 insertions, 0 deletions
diff --git a/pc-bios/optionrom/optrom_fw_cfg.h b/pc-bios/optionrom/optrom_fw_cfg.h
new file mode 100644
index 0000000000..a3660a5200
--- /dev/null
+++ b/pc-bios/optionrom/optrom_fw_cfg.h
@@ -0,0 +1,92 @@
+/*
+ * Common Option ROM Functions for fw_cfg
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (c) 2015-2019 Red Hat Inc.
+ *   Authors:
+ *     Marc Marí <marc.mari.barcelo@gmail.com>
+ *     Richard W.M. Jones <rjones@redhat.com>
+ *     Stefano Garzarella <sgarzare@redhat.com>
+ */
+
+#ifndef OPTROM_FW_CFG_H
+#define OPTROM_FW_CFG_H
+
+#include "../../include/standard-headers/linux/qemu_fw_cfg.h"
+
+#define BIOS_CFG_IOPORT_CFG     0x510
+#define BIOS_CFG_IOPORT_DATA    0x511
+#define BIOS_CFG_DMA_ADDR_HIGH  0x514
+#define BIOS_CFG_DMA_ADDR_LOW   0x518
+
+static __attribute__((unused))
+void bios_cfg_select(uint16_t key)
+{
+    outw(key, BIOS_CFG_IOPORT_CFG);
+}
+
+static __attribute__((unused))
+void bios_cfg_read_entry_io(void *buf, uint16_t entry, uint32_t len)
+{
+    bios_cfg_select(entry);
+    insb(BIOS_CFG_IOPORT_DATA, buf, len);
+}
+
+/*
+ * clang is happy to inline this function, and bloats the
+ * ROM.
+ */
+static __attribute__((__noinline__)) __attribute__((unused))
+void bios_cfg_read_entry_dma(void *buf, uint16_t entry, uint32_t len)
+{
+    struct fw_cfg_dma_access access;
+    uint32_t control = (entry << 16) | FW_CFG_DMA_CTL_SELECT
+                        | FW_CFG_DMA_CTL_READ;
+
+    access.address = cpu_to_be64((uint64_t)(uint32_t)buf);
+    access.length = cpu_to_be32(len);
+    access.control = cpu_to_be32(control);
+
+    barrier();
+
+    outl(cpu_to_be32((uint32_t)&access), BIOS_CFG_DMA_ADDR_LOW);
+
+    while (be32_to_cpu(access.control) & ~FW_CFG_DMA_CTL_ERROR) {
+        barrier();
+    }
+}
+
+static __attribute__((unused))
+void bios_cfg_read_entry(void *buf, uint16_t entry, uint32_t len,
+                         uint32_t version)
+{
+    if (version & FW_CFG_VERSION_DMA) {
+        bios_cfg_read_entry_dma(buf, entry, len);
+    } else {
+        bios_cfg_read_entry_io(buf, entry, len);
+    }
+}
+
+static __attribute__((unused))
+uint32_t bios_cfg_version(void)
+{
+    uint32_t version;
+
+    bios_cfg_read_entry_io(&version, FW_CFG_ID, sizeof(version));
+
+    return version;
+}
+
+#endif /* OPTROM_FW_CFG_H */