Blame SOURCES/kvm-hw-i386-pc_sysfw-support-two-flash-drives.patch

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From e1fb6e4160e9d9eb1c7b01ea4b5b3a94c953c379 Mon Sep 17 00:00:00 2001
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From: Laszlo Ersek <lersek@redhat.com>
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Date: Sat, 11 Jan 2014 18:00:03 +0100
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Subject: [PATCH 13/22] hw/i386/pc_sysfw: support two flash drives
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RH-Author: Laszlo Ersek <lersek@redhat.com>
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Message-id: <1389463208-6278-14-git-send-email-lersek@redhat.com>
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Patchwork-id: 56626
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O-Subject: [RHEL-7.0 qemu-kvm PATCH 13/18] hw/i386/pc_sysfw: support two flash drives
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Bugzilla: 1032346
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Amos Kong <akong@redhat.com>
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RH-Acked-by: Andrew Jones <drjones@redhat.com>
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This patch allows the user to usefully specify
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  -drive file=img_1,if=pflash,format=raw,readonly \
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  -drive file=img_2,if=pflash,format=raw
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on the command line. The flash images will be mapped under 4G in their
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reverse unit order -- that is, with their base addresses progressing
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downwards, in increasing unit order.
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(The unit number increases with command line order if not explicitly
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specified.)
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This accommodates the following use case: suppose that OVMF is split in
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two parts, a writeable host file for non-volatile variable storage, and a
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read-only part for bootstrap and decompressible executable code.
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The binary code part would be read-only, centrally managed on the host
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system, and passed in as unit 0. The variable store would be writeable,
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VM-specific, and passed in as unit 1.
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  00000000ffe00000-00000000ffe1ffff (prio 0, R-): system.flash1
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  00000000ffe20000-00000000ffffffff (prio 0, R-): system.flash0
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(If the guest tries to write to the flash range that is backed by the
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read-only drive, pflash_update() is never called; various flash
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programming/erase errors are returned to the guest instead. See the
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callers of pflash_update(), and the initialization of "pfl->ro", in
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"hw/block/pflash_cfi01.c".)
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Signed-off-by: Laszlo Ersek <lersek@redhat.com>
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Reviewed-by: Markus Armbruster <armbru@redhat.com>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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(cherry picked from commit 637a5acb46b36a25b506ba6545e9a53350585b03)
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---
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 hw/i386/pc_sysfw.c | 105 +++++++++++++++++++++++++++++++++++++++++++----------
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 1 file changed, 86 insertions(+), 19 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/i386/pc_sysfw.c |  105 ++++++++++++++++++++++++++++++++++++++++++---------
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 1 files changed, 86 insertions(+), 19 deletions(-)
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diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
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index eb56dee..6f5ecde 100644
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--- a/hw/i386/pc_sysfw.c
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+++ b/hw/i386/pc_sysfw.c
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@@ -72,35 +72,102 @@ static void pc_isa_bios_init(MemoryRegion *rom_memory,
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     memory_region_set_readonly(isa_bios, true);
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 }
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-static void pc_system_flash_init(MemoryRegion *rom_memory,
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-                                 DriveInfo *pflash_drv)
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+#define FLASH_MAP_UNIT_MAX 2
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+
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+/* We don't have a theoretically justifiable exact lower bound on the base
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+ * address of any flash mapping. In practice, the IO-APIC MMIO range is
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+ * [0xFEE00000..0xFEE01000[ -- see IO_APIC_DEFAULT_ADDRESS --, leaving free
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+ * only 18MB-4KB below 4G. For now, restrict the cumulative mapping to 8MB in
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+ * size.
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+ */
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+#define FLASH_MAP_BASE_MIN ((hwaddr)(0x100000000ULL - 8*1024*1024))
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+
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+/* This function maps flash drives from 4G downward, in order of their unit
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+ * numbers. The mapping starts at unit#0, with unit number increments of 1, and
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+ * stops before the first missing flash drive, or before
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+ * unit#FLASH_MAP_UNIT_MAX, whichever is reached first.
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+ *
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+ * Addressing within one flash drive is of course not reversed.
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+ *
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+ * An error message is printed and the process exits if:
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+ * - the size of the backing file for a flash drive is non-positive, or not a
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+ *   multiple of the required sector size, or
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+ * - the current mapping's base address would fall below FLASH_MAP_BASE_MIN.
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+ *
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+ * The drive with unit#0 (if available) is mapped at the highest address, and
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+ * it is passed to pc_isa_bios_init(). Merging several drives for isa-bios is
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+ * not supported.
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+ */
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+static void pc_system_flash_init(MemoryRegion *rom_memory)
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 {
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+    int unit;
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+    DriveInfo *pflash_drv;
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     BlockDriverState *bdrv;
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     int64_t size;
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-    hwaddr phys_addr;
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+    char *fatal_errmsg = NULL;
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+    hwaddr phys_addr = 0x100000000ULL;
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     int sector_bits, sector_size;
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     pflash_t *system_flash;
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     MemoryRegion *flash_mem;
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+    char name[64];
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-    bdrv = pflash_drv->bdrv;
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-    size = bdrv_getlength(pflash_drv->bdrv);
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     sector_bits = 12;
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     sector_size = 1 << sector_bits;
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-    if ((size % sector_size) != 0) {
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-        fprintf(stderr,
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-                "qemu: PC system firmware (pflash) must be a multiple of 0x%x\n",
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-                sector_size);
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-        exit(1);
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+    for (unit = 0;
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+         (unit < FLASH_MAP_UNIT_MAX &&
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+          (pflash_drv = drive_get(IF_PFLASH, 0, unit)) != NULL);
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+         ++unit) {
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+        bdrv = pflash_drv->bdrv;
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+        size = bdrv_getlength(bdrv);
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+        if (size < 0) {
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+            fatal_errmsg = g_strdup_printf("failed to get backing file size");
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+        } else if (size == 0) {
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+            fatal_errmsg = g_strdup_printf("PC system firmware (pflash) "
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+                               "cannot have zero size");
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+        } else if ((size % sector_size) != 0) {
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+            fatal_errmsg = g_strdup_printf("PC system firmware (pflash) "
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+                               "must be a multiple of 0x%x", sector_size);
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+        } else if (phys_addr < size || phys_addr - size < FLASH_MAP_BASE_MIN) {
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+            fatal_errmsg = g_strdup_printf("oversized backing file, pflash "
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+                               "segments cannot be mapped under "
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+                               TARGET_FMT_plx, FLASH_MAP_BASE_MIN);
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+        }
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+        if (fatal_errmsg != NULL) {
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+            Location loc;
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+
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+            /* push a new, "none" location on the location stack; overwrite its
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+             * contents with the location saved in the option; print the error
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+             * (includes location); pop the top
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+             */
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+            loc_push_none(&loc);
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+            if (pflash_drv->opts != NULL) {
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+                qemu_opts_loc_restore(pflash_drv->opts);
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+            }
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+            error_report("%s", fatal_errmsg);
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+            loc_pop(&loc);
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+            g_free(fatal_errmsg);
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+            exit(1);
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+        }
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+
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+        phys_addr -= size;
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+
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+        /* pflash_cfi01_register() creates a deep copy of the name */
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+        snprintf(name, sizeof name, "system.flash%d", unit);
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+        system_flash = pflash_cfi01_register(phys_addr, NULL /* qdev */, name,
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+                                             size, bdrv, sector_size,
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+                                             size >> sector_bits,
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+                                             1      /* width */,
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+                                             0x0000 /* id0 */,
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+                                             0x0000 /* id1 */,
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+                                             0x0000 /* id2 */,
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+                                             0x0000 /* id3 */,
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+                                             0      /* be */);
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+        if (unit == 0) {
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+            flash_mem = pflash_cfi01_get_memory(system_flash);
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+            pc_isa_bios_init(rom_memory, flash_mem, size);
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+        }
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     }
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-
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-    phys_addr = 0x100000000ULL - size;
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-    system_flash = pflash_cfi01_register(phys_addr, NULL, "system.flash", size,
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-                                         bdrv, sector_size, size >> sector_bits,
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-                                         1, 0x0000, 0x0000, 0x0000, 0x0000, 0);
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-    flash_mem = pflash_cfi01_get_memory(system_flash);
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-
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-    pc_isa_bios_init(rom_memory, flash_mem, size);
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 }
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 static void old_pc_system_rom_init(MemoryRegion *rom_memory, bool isapc_ram_fw)
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@@ -181,5 +248,5 @@ void pc_system_firmware_init(MemoryRegion *rom_memory, bool isapc_ram_fw)
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         exit(1);
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     }
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-    pc_system_flash_init(rom_memory, pflash_drv);
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+    pc_system_flash_init(rom_memory);
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 }
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-- 
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1.7.1
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