aspeed/smc: Only wire flash devices at reset

The Aspeed machines have many Static Memory Controllers (SMC), up to
8, which can only drive flash memory devices. Commit 27a2c66c92ec
("aspeed/smc: Wire CS lines at reset") tried to ease the definitions
of these devices by allowing flash devices from the command line to be
attached to a SSI bus. For that, the wiring of the CS lines of the
Aspeed SMC controller was moved at reset. Two assumptions are made
though, first that the device has a SSI_GPIO_CS GPIO line, which is
not always the case, and second that it is a flash device.

Correct this problem by ensuring that the devices attached to the bus
are of the correct flash type. This fixes a QEMU abort when devices
without a CS line, such as the max111x, are passed on the command
line.

While at it, export TYPE_M25P80 used in the Xilinx Versal Virtual
machine.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2228
Fixes: 27a2c66c92ec ("aspeed/smc: Wire CS lines at reset")
Reported-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
[ clg: minor fixes in the commit log ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>

4 files changed, 13 insertions, 2 deletions

diff --git a/hw/arm/xlnx-versal-virt.c b/hw/arm/xlnx-versal-virt.c
index bfaed1a..962f98f 100644
--- a/hw/arm/xlnx-versal-virt.c
+++ b/hw/arm/xlnx-versal-virt.c
@@ -13,6 +13,7 @@
 #include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "sysemu/device_tree.h"
+#include "hw/block/flash.h"
 #include "hw/boards.h"
 #include "hw/sysbus.h"
 #include "hw/arm/fdt.h"
@@ -759,7 +760,7 @@ static void versal_virt_init(MachineState *machine)
             flash_klass = object_class_by_name(s->ospi_model);
             if (!flash_klass ||
                 object_class_is_abstract(flash_klass) ||
-                !object_class_dynamic_cast(flash_klass, "m25p80-generic")) {
+                !object_class_dynamic_cast(flash_klass, TYPE_M25P80)) {
                 error_setg(&error_fatal, "'%s' is either abstract or"
                        " not a subtype of m25p80", s->ospi_model);
                 return;
diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
index 08a00a6..8dec134 100644
--- a/hw/block/m25p80.c
+++ b/hw/block/m25p80.c
@@ -515,7 +515,6 @@ struct M25P80Class {
     FlashPartInfo *pi;
 };
 
-#define TYPE_M25P80 "m25p80-generic"
 OBJECT_DECLARE_TYPE(Flash, M25P80Class, M25P80)
 
 static inline Manufacturer get_man(Flash *s)
diff --git a/hw/ssi/aspeed_smc.c b/hw/ssi/aspeed_smc.c
index 3c93936..6e1a84c 100644
--- a/hw/ssi/aspeed_smc.c
+++ b/hw/ssi/aspeed_smc.c
@@ -23,6 +23,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "hw/block/flash.h"
 #include "hw/sysbus.h"
 #include "migration/vmstate.h"
 #include "qemu/log.h"
@@ -695,6 +696,14 @@ static void aspeed_smc_reset(DeviceState *d)
     for (i = 0; i < asc->cs_num_max; i++) {
         DeviceState *dev = ssi_get_cs(s->spi, i);
         if (dev) {
+            Object *o = OBJECT(dev);
+
+            if (!object_dynamic_cast(o, TYPE_M25P80)) {
+                warn_report("Aspeed SMC %s.%d : Invalid %s device type",
+                            BUS(s->spi)->name, i, object_get_typename(o));
+                continue;
+            }
+
             qemu_irq cs_line = qdev_get_gpio_in_named(dev, SSI_GPIO_CS, 0);
             qdev_connect_gpio_out_named(DEVICE(s), "cs", i, cs_line);
         }
diff --git a/include/hw/block/flash.h b/include/hw/block/flash.h
index de93756..2b5ccd9 100644
--- a/include/hw/block/flash.h
+++ b/include/hw/block/flash.h
@@ -78,6 +78,8 @@ extern const VMStateDescription vmstate_ecc_state;
 
 /* m25p80.c */
 
+#define TYPE_M25P80 "m25p80-generic"
+
 BlockBackend *m25p80_get_blk(DeviceState *dev);
 
 #endif