[Qemu-block] [PATCH v2 5/9] hw/block/pflash_cfi01: Add the DeviceReset() handler

[Philippe Mathieu-Daudé]

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

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

This pflash device is a child of TYPE_DEVICE.
The TYPE_DEVICE interface provide a DeviceReset handler which will
be called after the device is realized, and each time the machine
resets itself.

To avoid incoherent states when the machine resets (see but report
below), factor out the reset code into pflash_cfi01_system_reset,
and register the method as a device reset callback.

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1678713
Reported-by: Laszlo Ersek <address@hidden>
Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
---
 hw/block/pflash_cfi01.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index dd1dfd266b..8d632ea941 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -763,8 +763,6 @@ static void pflash_cfi01_realize(DeviceState *dev, Error 
**errp)
         pfl->max_device_width = pfl->device_width;
     }
 
-    pflash_mode_read_array(pfl);
-    pfl->status = 0x80; /* WSM ready */
     /* Hardcoded CFI table */
     /* Standard "QRY" string */
     pfl->cfi_table[0x10] = 'Q';
@@ -852,6 +850,18 @@ 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);
+
+    pflash_mode_read_array(pfl);
+    /*
+     * 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,
@@ -896,6 +906,7 @@ 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;
-- 
2.20.1