From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

Allow the VIA IDE controller to switch between both legacy and native modes by
calling pci_ide_update_mode() to reconfigure the device whenever PCI_CLASS_PROG
is updated.

This patch moves the initial setting of PCI_CLASS_PROG from via_ide_realize() to
via_ide_reset(), and removes the direct setting of PCI_INTERRUPT_PIN during PCI
bus reset since this is now managed by pci_ide_update_mode(). This ensures that
the device configuration is always consistent with respect to the currently
selected mode.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-ID: <20231116103355.588580-5-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/ide/via.c | 39 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/hw/ide/via.c b/hw/ide/via.c
index 87b134083a..2d3124ebd7 100644
--- a/hw/ide/via.c
+++ b/hw/ide/via.c
@@ -28,6 +28,7 @@
 #include "hw/pci/pci.h"
 #include "migration/vmstate.h"
 #include "qemu/module.h"
+#include "qemu/range.h"
 #include "sysemu/dma.h"
 #include "hw/isa/vt82c686.h"
 #include "hw/ide/pci.h"
@@ -128,11 +129,14 @@ static void via_ide_reset(DeviceState *dev)
         ide_bus_reset(&d->bus[i]);
     }
 
+    pci_config_set_prog_interface(pci_conf, 0x8a); /* legacy mode */
+    pci_ide_update_mode(d);
+
     pci_set_word(pci_conf + PCI_COMMAND, PCI_COMMAND_IO | PCI_COMMAND_WAIT);
     pci_set_word(pci_conf + PCI_STATUS, PCI_STATUS_FAST_BACK |
                  PCI_STATUS_DEVSEL_MEDIUM);
 
-    pci_set_long(pci_conf + PCI_INTERRUPT_LINE, 0x0000010e);
+    pci_set_byte(pci_conf + PCI_INTERRUPT_LINE, 0xe);
 
     /* IDE chip enable, IDE configuration 1/2, IDE FIFO Configuration*/
     pci_set_long(pci_conf + 0x40, 0x0a090600);
@@ -154,6 +158,36 @@ static void via_ide_reset(DeviceState *dev)
     pci_set_long(pci_conf + 0xc0, 0x00020001);
 }
 
+static uint32_t via_ide_cfg_read(PCIDevice *pd, uint32_t addr, int len)
+{
+    uint32_t val = pci_default_read_config(pd, addr, len);
+    uint8_t mode = pd->config[PCI_CLASS_PROG];
+
+    if ((mode & 0xf) == 0xa && ranges_overlap(addr, len,
+                                              PCI_BASE_ADDRESS_0, 16)) {
+        /* BARs always read back zero in legacy mode */
+        for (int i = addr; i < addr + len; i++) {
+            if (i >= PCI_BASE_ADDRESS_0 && i < PCI_BASE_ADDRESS_0 + 16) {
+                val &= ~(0xffULL << ((i - addr) << 3));
+            }
+        }
+    }
+
+    return val;
+}
+
+static void via_ide_cfg_write(PCIDevice *pd, uint32_t addr,
+                              uint32_t val, int len)
+{
+    PCIIDEState *d = PCI_IDE(pd);
+
+    pci_default_write_config(pd, addr, val, len);
+
+    if (range_covers_byte(addr, len, PCI_CLASS_PROG)) {
+        pci_ide_update_mode(d);
+    }
+}
+
 static void via_ide_realize(PCIDevice *dev, Error **errp)
 {
     PCIIDEState *d = PCI_IDE(dev);
@@ -161,7 +195,6 @@ static void via_ide_realize(PCIDevice *dev, Error **errp)
     uint8_t *pci_conf = dev->config;
     int i;
 
-    pci_config_set_prog_interface(pci_conf, 0x8a); /* legacy mode */
     pci_set_long(pci_conf + PCI_CAPABILITY_LIST, 0x000000c0);
     dev->wmask[PCI_INTERRUPT_LINE] = 0;
     dev->wmask[PCI_CLASS_PROG] = 5;
@@ -216,6 +249,8 @@ static void via_ide_class_init(ObjectClass *klass, void *data)
     /* Reason: only works as function of VIA southbridge */
     dc->user_creatable = false;
 
+    k->config_read = via_ide_cfg_read;
+    k->config_write = via_ide_cfg_write;
     k->realize = via_ide_realize;
     k->exit = via_ide_exitfn;
     k->vendor_id = PCI_VENDOR_ID_VIA;
-- 
2.42.0