Re: [PATCH 1/2] ide/pci.c: introduce pci_ide_update_mode() function

[Bernhard Beschow]

Am 19. Oktober 2023 13:04:51 UTC schrieb Mark Cave-Ayland 
<mark.cave-ayland@ilande.co.uk>:
>This function reads the value of the PCI_CLASS_PROG register for PCI IDE
>controllers and configures the PCI BARs and/or IDE ioports accordingly.
>
>In the case where we switch to legacy mode, the PCI BARs are set to return zero
>(as suggested in the "PCI IDE Controller" specification), the legacy IDE 
>ioports
>are enabled, and the PCI interrupt pin cleared to indicate legacy IRQ routing.
>
>Conversely when we switch to native mode, the legacy IDE ioports are disabled
>and the PCI interrupt pin set to indicate native IRQ routing. The contents of
>the PCI BARs are unspecified, but this is not an issue since if a PCI IDE
>controller has been switched to native mode then its BARs will need to be
>programmed.
>
>Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
>---
> hw/ide/pci.c         | 90 ++++++++++++++++++++++++++++++++++++++++++++
> include/hw/ide/pci.h |  1 +
> 2 files changed, 91 insertions(+)
>
>diff --git a/hw/ide/pci.c b/hw/ide/pci.c
>index a25b352537..9eb30af632 100644
>--- a/hw/ide/pci.c
>+++ b/hw/ide/pci.c
>@@ -104,6 +104,96 @@ const MemoryRegionOps pci_ide_data_le_ops = {
>     .endianness = DEVICE_LITTLE_ENDIAN,
> };
> 
>+static const MemoryRegionPortio ide_portio_list[] = {
>+    { 0, 8, 1, .read = ide_ioport_read, .write = ide_ioport_write },
>+    { 0, 1, 2, .read = ide_data_readw, .write = ide_data_writew },
>+    { 0, 1, 4, .read = ide_data_readl, .write = ide_data_writel },
>+    PORTIO_END_OF_LIST(),
>+};
>+
>+static const MemoryRegionPortio ide_portio2_list[] = {
>+    { 0, 1, 1, .read = ide_status_read, .write = ide_ctrl_write },
>+    PORTIO_END_OF_LIST(),
>+};
>+
>+void pci_ide_update_mode(PCIIDEState *s)
>+{
>+    PCIDevice *d = PCI_DEVICE(s);
>+    uint8_t mode = d->config[PCI_CLASS_PROG];
>+
>+    switch (mode) {

Maybe

  switch (mode & 0xf) {

here such that only the bits relevant to the PCI IDE controller specification 
are analyzed? Then we can omit the high '8' nibble in the case labels which 
indicate bus master capability which is obviously out of scope of the switch 
statement (since you're not touching the BM DMA BAR).

>+    case 0x8a:

Perhaps we could add a

  case 0x0:

in front of the above label for compatibility with PIIX-IDE? That way, this 
function could be reused in the future for resetting PIIX-IDE.

>+        /* Both channels legacy mode */
>+
>+        /* Zero BARs */
>+        pci_set_long(d->config + PCI_BASE_ADDRESS_0, 0x0);
>+        pci_set_long(d->config + PCI_BASE_ADDRESS_1, 0x0);
>+        pci_set_long(d->config + PCI_BASE_ADDRESS_2, 0x0);
>+        pci_set_long(d->config + PCI_BASE_ADDRESS_3, 0x0);
>+
>+        /* Clear interrupt pin */
>+        pci_config_set_interrupt_pin(d->config, 0);

Do we really need to toggle the interrupt pin in this function? Or is this 
VIA-specific? This byte isn't even defined for PIIX-IDE.

Best regards,
Bernhard

>+
>+        /* Add legacy IDE ports */
>+        if (!s->bus[0].portio_list.owner) {
>+            portio_list_init(&s->bus[0].portio_list, OBJECT(d),
>+                             ide_portio_list, &s->bus[0], "ide");
>+            portio_list_add(&s->bus[0].portio_list,
>+                            pci_address_space_io(d), 0x1f0);
>+        }
>+
>+        if (!s->bus[0].portio2_list.owner) {
>+            portio_list_init(&s->bus[0].portio2_list, OBJECT(d),
>+                             ide_portio2_list, &s->bus[0], "ide");
>+            portio_list_add(&s->bus[0].portio2_list,
>+                            pci_address_space_io(d), 0x3f6);
>+        }
>+
>+        if (!s->bus[1].portio_list.owner) {
>+            portio_list_init(&s->bus[1].portio_list, OBJECT(d),
>+                                ide_portio_list, &s->bus[1], "ide");
>+            portio_list_add(&s->bus[1].portio_list,
>+                            pci_address_space_io(d), 0x170);
>+        }
>+
>+        if (!s->bus[1].portio2_list.owner) {
>+            portio_list_init(&s->bus[1].portio2_list, OBJECT(d),
>+                             ide_portio2_list, &s->bus[1], "ide");
>+            portio_list_add(&s->bus[1].portio2_list,
>+                            pci_address_space_io(d), 0x376);
>+        }
>+        break;
>+
>+    case 0x8f:
>+        /* Both channels native mode */
>+
>+        /* Set interrupt pin */
>+        pci_config_set_interrupt_pin(d->config, 1);
>+
>+        /* Remove legacy IDE ports */
>+        if (s->bus[0].portio_list.owner) {
>+            portio_list_del(&s->bus[0].portio_list);
>+            portio_list_destroy(&s->bus[0].portio_list);
>+        }
>+
>+        if (s->bus[0].portio2_list.owner) {
>+            portio_list_del(&s->bus[0].portio2_list);
>+            portio_list_destroy(&s->bus[0].portio2_list);
>+        }
>+
>+        if (s->bus[1].portio_list.owner) {
>+            portio_list_del(&s->bus[1].portio_list);
>+            portio_list_destroy(&s->bus[1].portio_list);
>+        }
>+
>+        if (s->bus[1].portio2_list.owner) {
>+            portio_list_del(&s->bus[1].portio2_list);
>+            portio_list_destroy(&s->bus[1].portio2_list);
>+        }
>+        break;
>+    }
>+}
>+
> static IDEState *bmdma_active_if(BMDMAState *bmdma)
> {
>     assert(bmdma->bus->retry_unit != (uint8_t)-1);
>diff --git a/include/hw/ide/pci.h b/include/hw/ide/pci.h
>index 1ff469de87..a814a0a7c3 100644
>--- a/include/hw/ide/pci.h
>+++ b/include/hw/ide/pci.h
>@@ -61,6 +61,7 @@ void bmdma_cmd_writeb(BMDMAState *bm, uint32_t val);
> void bmdma_status_writeb(BMDMAState *bm, uint32_t val);
> extern MemoryRegionOps bmdma_addr_ioport_ops;
> void pci_ide_create_devs(PCIDevice *dev);
>+void pci_ide_update_mode(PCIIDEState *s);
> 
> extern const VMStateDescription vmstate_ide_pci;
> extern const MemoryRegionOps pci_ide_cmd_le_ops;