Author: stepan Date: 2006-08-12 11:52:34 +0200 (Sat, 12 Aug 2006) New Revision: 73
Modified: openbios-devel/drivers/esp.c Log:
From Paul Brook:
The ESP SCSI driver currently doesn't check whether a DMA requests has completed before checking its status. On older qemu versions this works ok because DMA happens instantly. On never qemu DMA can take an indeterminate amount of time ooto complete, just like on real hardware.
The patch waits for the controller to raise the DMA interrupt after initiating a DMA request.
Modified: openbios-devel/drivers/esp.c =================================================================== --- openbios-devel/drivers/esp.c 2006-07-28 21:44:07 UTC (rev 72) +++ openbios-devel/drivers/esp.c 2006-08-12 09:52:34 UTC (rev 73) @@ -113,6 +113,8 @@ esp->espdma.regs->cond_reg = 0; // Set ATN, issue command esp->ll->regs[ESP_CMD] = ESP_CMD_SELA | ESP_CMD_DMA; + // Wait for DMA to complete. Can this fail? + while ((esp->espdma.regs->cond_reg & DMA_HNDL_INTR) == 0) /* no-op */; // Check status status = esp->ll->regs[ESP_STATUS];
@@ -129,6 +131,8 @@ esp->espdma.regs->cond_reg = DMA_ST_WRITE; // Transfer esp->ll->regs[ESP_CMD] = ESP_CMD_TI | ESP_CMD_DMA; + // Wait for DMA to complete + while ((esp->espdma.regs->cond_reg & DMA_HNDL_INTR) == 0) /* no-op */; // Check status status = esp->ll->regs[ESP_STATUS];