hw/block/pflash_cfi01: Add missing DeviceReset() handler

To avoid incoherent states when the machine resets (see bug report
below), add the device reset callback.

A "system reset" sets the device state machine in READ_ARRAY mode
and, after some delay, set the SR.7 READY bit.

Since we do not model timings, we set the SR.7 bit directly.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1678713
Reported-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
[Laszlo Ersek: Regression tested EDK2 OVMF IA32X64, ArmVirtQemu Aarch64
 https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg04373.html]
Message-Id: <20190718104837.13905-2-philmd@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index 435be1e..a1ec1fa 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -865,6 +865,24 @@ static void pflash_cfi01_realize(DeviceState *dev, Error **errp)
     pfl->cfi_table[0x3f] = 0x01; /* Number of protection fields */
 }
 
+static void pflash_cfi01_system_reset(DeviceState *dev)
+{
+    PFlashCFI01 *pfl = PFLASH_CFI01(dev);
+
+    /*
+     * The command 0x00 is not assigned by the CFI open standard,
+     * but QEMU historically uses it for the READ_ARRAY command (0xff).
+     */
+    pfl->cmd = 0x00;
+    pfl->wcycle = 0;
+    memory_region_rom_device_set_romd(&pfl->mem, true);
+    /*
+     * The WSM ready timer occurs at most 150ns after system reset.
+     * This model deliberately ignores this delay.
+     */
+    pfl->status = 0x80;
+}
+
 static Property pflash_cfi01_properties[] = {
     DEFINE_PROP_DRIVE("drive", PFlashCFI01, blk),
     /* num-blocks is the number of blocks actually visible to the guest,
@@ -909,6 +927,7 @@ static void pflash_cfi01_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
+    dc->reset = pflash_cfi01_system_reset;
     dc->realize = pflash_cfi01_realize;
     dc->props = pflash_cfi01_properties;
     dc->vmsd = &vmstate_pflash;