[PULL 30/36] hw/scsi/esp-pci: generate PCI interrupt from separate ESP and PCI sources

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

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

The am53c974/dc390 PCI interrupt has two separate sources: the first is from the
internal ESP device, and the second is from the PCI DMA transfer logic.

Update the ESP interrupt handler so that it sets DMA_STAT_SCSIINT rather than
driving the PCI IRQ directly, and introduce a new esp_pci_update_irq() function
to generate the correct PCI IRQ level. In particular this fixes spurious interrupts
being generated by setting DMA_STAT_DONE at the end of a transfer if DMA_CMD_INTE_D
isn't set in the DMA_CMD register.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Message-ID: <20240112131529.515642-3-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/scsi/esp-pci.c | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/hw/scsi/esp-pci.c b/hw/scsi/esp-pci.c
index 7117725371..15dc3c004d 100644
--- a/hw/scsi/esp-pci.c
+++ b/hw/scsi/esp-pci.c
@@ -77,6 +77,29 @@ struct PCIESPState {
     ESPState esp;
 };
 
+static void esp_pci_update_irq(PCIESPState *pci)
+{
+    int scsi_level = !!(pci->dma_regs[DMA_STAT] & DMA_STAT_SCSIINT);
+    int dma_level = (pci->dma_regs[DMA_CMD] & DMA_CMD_INTE_D) ?
+                    !!(pci->dma_regs[DMA_STAT] & DMA_STAT_DONE) : 0;
+    int level = scsi_level || dma_level;
+
+    pci_set_irq(PCI_DEVICE(pci), level);
+}
+
+static void esp_irq_handler(void *opaque, int irq_num, int level)
+{
+    PCIESPState *pci = PCI_ESP(opaque);
+
+    if (level) {
+        pci->dma_regs[DMA_STAT] |= DMA_STAT_SCSIINT;
+    } else {
+        pci->dma_regs[DMA_STAT] &= ~DMA_STAT_SCSIINT;
+    }
+
+    esp_pci_update_irq(pci);
+}
+
 static void esp_pci_handle_idle(PCIESPState *pci, uint32_t val)
 {
     ESPState *s = &pci->esp;
@@ -151,6 +174,7 @@ static void esp_pci_dma_write(PCIESPState *pci, uint32_t saddr, uint32_t val)
             /* clear some bits on write */
             uint32_t mask = DMA_STAT_ERROR | DMA_STAT_ABORT | DMA_STAT_DONE;
             pci->dma_regs[DMA_STAT] &= ~(val & mask);
+            esp_pci_update_irq(pci);
         }
         break;
     default:
@@ -161,17 +185,14 @@ static void esp_pci_dma_write(PCIESPState *pci, uint32_t saddr, uint32_t val)
 
 static uint32_t esp_pci_dma_read(PCIESPState *pci, uint32_t saddr)
 {
-    ESPState *s = &pci->esp;
     uint32_t val;
 
     val = pci->dma_regs[saddr];
     if (saddr == DMA_STAT) {
-        if (s->rregs[ESP_RSTAT] & STAT_INT) {
-            val |= DMA_STAT_SCSIINT;
-        }
         if (!(pci->sbac & SBAC_STATUS)) {
             pci->dma_regs[DMA_STAT] &= ~(DMA_STAT_ERROR | DMA_STAT_ABORT |
                                          DMA_STAT_DONE);
+            esp_pci_update_irq(pci);
         }
     }
 
@@ -350,6 +371,7 @@ static void esp_pci_command_complete(SCSIRequest *req, size_t resid)
     esp_command_complete(req, resid);
     pci->dma_regs[DMA_WBC] = 0;
     pci->dma_regs[DMA_STAT] |= DMA_STAT_DONE;
+    esp_pci_update_irq(pci);
 }
 
 static const struct SCSIBusInfo esp_pci_scsi_info = {
@@ -386,7 +408,7 @@ static void esp_pci_scsi_realize(PCIDevice *dev, Error **errp)
                           "esp-io", 0x80);
 
     pci_register_bar(dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &pci->io);
-    s->irq = pci_allocate_irq(dev);
+    s->irq = qemu_allocate_irq(esp_irq_handler, pci, 0);
 
     scsi_bus_init(&s->bus, sizeof(s->bus), d, &esp_pci_scsi_info);
 }
-- 
2.41.0