[SCSI] mac_esp: fix for quadras with two esp chips

On the Quadra 900 and 950 there are two ESP chips sharing one IRQ. Because the shared IRQ is edge-triggered, we must make sure that an IRQ transition from one chip doesn't go unnoticed when the shared IRQ is already active due to the other. This patch prevents interrupts getting lost so that both SCSI busses may be used simultaneously. Signed-off-by: Finn Thain <fthain@telegraphics.com.au> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] mac_esp: fix for quadras with two esp chips
On the Quadra 900 and 950 there are two ESP chips sharing one IRQ. Because the shared IRQ is edge-triggered, we must make sure that an IRQ transition from one chip doesn't go unnoticed when the shared IRQ is already active due to the other. This patch prevents interrupts getting lost so that both SCSI busses may be used simultaneously. Signed-off-by: Finn Thain <fthain@telegraphics.com.au> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Finn Thain · James Bottomley
1 parent 09e13e9167
Showing 1 changed file with 58 additions and 23 deletions Side-by-side Diff
drivers/scsi/mac_esp.c
@@ -53,7 +53,8 @@
 	void __iomem *pdma_io;
 	int error;
 };
-static struct platform_device *internal_esp, *external_esp;
+static struct platform_device *internal_pdev, *external_pdev;
+static struct esp *esp_chips[2];
  
 #define MAC_ESP_GET_PRIV(esp) ((struct mac_esp_priv *) \
 			       platform_get_drvdata((struct platform_device *) \
@@ -443,6 +444,32 @@
 	return dma_len > 0xFFFF ? 0xFFFF : dma_len;
 }
  
+static irqreturn_t mac_scsi_esp_intr(int irq, void *dev_id)
+{
+	int got_intr;
+
+	/*
+	 * This is an edge triggered IRQ, so we have to be careful to
+	 * avoid missing a transition when it is shared by two ESP devices.
+	 */
+
+	do {
+		got_intr = 0;
+		if (esp_chips[0] &&
+		    (mac_esp_read8(esp_chips[0], ESP_STATUS) & ESP_STAT_INTR)) {
+			(void)scsi_esp_intr(irq, esp_chips[0]);
+			got_intr = 1;
+		}
+		if (esp_chips[1] &&
+		    (mac_esp_read8(esp_chips[1], ESP_STATUS) & ESP_STAT_INTR)) {
+			(void)scsi_esp_intr(irq, esp_chips[1]);
+			got_intr = 1;
+		}
+	} while (got_intr);
+
+	return IRQ_HANDLED;
+}
+
 static struct esp_driver_ops mac_esp_ops = {
 	.esp_write8       = mac_esp_write8,
 	.esp_read8        = mac_esp_read8,
@@ -557,10 +584,16 @@
 	}
  
 	host->irq = IRQ_MAC_SCSI;
-	err = request_irq(host->irq, scsi_esp_intr, IRQF_SHARED, "Mac ESP",
-			  esp);
-	if (err < 0)
-		goto fail_free_priv;
+	esp_chips[dev->id] = esp;
+	mb();
+	if (esp_chips[!dev->id] == NULL) {
+		err = request_irq(host->irq, mac_scsi_esp_intr, 0,
+		                  "Mac ESP", NULL);
+		if (err < 0) {
+			esp_chips[dev->id] = NULL;
+			goto fail_free_priv;
+		}
+	}
  
 	err = scsi_esp_register(esp, &dev->dev);
 	if (err)
@@ -569,7 +602,8 @@
 	return 0;
  
 fail_free_irq:
-	free_irq(host->irq, esp);
+	if (esp_chips[!dev->id] == NULL)
+		free_irq(host->irq, esp);
 fail_free_priv:
 	kfree(mep);
 fail_free_command_block:
@@ -588,7 +622,9 @@
  
 	scsi_esp_unregister(esp);
  
-	free_irq(irq, esp);
+	esp_chips[dev->id] = NULL;
+	if (!(esp_chips[0] || esp_chips[1]))
+		free_irq(irq, NULL);
  
 	kfree(mep);
  
  
  
@@ -615,19 +651,18 @@
 	if (err)
 		return err;
  
-	internal_esp = platform_device_alloc(DRV_MODULE_NAME, 0);
-	if (internal_esp && platform_device_add(internal_esp)) {
-		platform_device_put(internal_esp);
-		internal_esp = NULL;
+	internal_pdev = platform_device_alloc(DRV_MODULE_NAME, 0);
+	if (internal_pdev && platform_device_add(internal_pdev)) {
+		platform_device_put(internal_pdev);
+		internal_pdev = NULL;
 	}
-
-	external_esp = platform_device_alloc(DRV_MODULE_NAME, 1);
-	if (external_esp && platform_device_add(external_esp)) {
-		platform_device_put(external_esp);
-		external_esp = NULL;
+	external_pdev = platform_device_alloc(DRV_MODULE_NAME, 1);
+	if (external_pdev && platform_device_add(external_pdev)) {
+		platform_device_put(external_pdev);
+		external_pdev = NULL;
 	}
  
-	if (internal_esp || external_esp) {
+	if (internal_pdev || external_pdev) {
 		return 0;
 	} else {
 		platform_driver_unregister(&esp_mac_driver);
  
@@ -639,13 +674,13 @@
 {
 	platform_driver_unregister(&esp_mac_driver);
  
-	if (internal_esp) {
-		platform_device_unregister(internal_esp);
-		internal_esp = NULL;
+	if (internal_pdev) {
+		platform_device_unregister(internal_pdev);
+		internal_pdev = NULL;
 	}
-	if (external_esp) {
-		platform_device_unregister(external_esp);
-		external_esp = NULL;
+	if (external_pdev) {
+		platform_device_unregister(external_pdev);
+		external_pdev = NULL;
 	}
 }
...	...	@@ -53,7 +53,8 @@
53	53	void __iomem *pdma_io;
54	54	int error;
55	55	};
56		-static struct platform_device internal_esp, external_esp;
	56	+static struct platform_device internal_pdev, external_pdev;
	57	+static struct esp *esp_chips[2];
57	58
58	59	#define MAC_ESP_GET_PRIV(esp) ((struct mac_esp_priv *) \
59	60	platform_get_drvdata((struct platform_device *) \
...	...	@@ -443,6 +444,32 @@
443	444	return dma_len > 0xFFFF ? 0xFFFF : dma_len;
444	445	}
445	446
	447	+static irqreturn_t mac_scsi_esp_intr(int irq, void *dev_id)
	448	+{
	449	+ int got_intr;
	450	+
	451	+ /*
	452	+ * This is an edge triggered IRQ, so we have to be careful to
	453	+ * avoid missing a transition when it is shared by two ESP devices.
	454	+ */
	455	+
	456	+ do {
	457	+ got_intr = 0;
	458	+ if (esp_chips[0] &&
	459	+ (mac_esp_read8(esp_chips[0], ESP_STATUS) & ESP_STAT_INTR)) {
	460	+ (void)scsi_esp_intr(irq, esp_chips[0]);
	461	+ got_intr = 1;
	462	+ }
	463	+ if (esp_chips[1] &&
	464	+ (mac_esp_read8(esp_chips[1], ESP_STATUS) & ESP_STAT_INTR)) {
	465	+ (void)scsi_esp_intr(irq, esp_chips[1]);
	466	+ got_intr = 1;
	467	+ }
	468	+ } while (got_intr);
	469	+
	470	+ return IRQ_HANDLED;
	471	+}
	472	+
446	473	static struct esp_driver_ops mac_esp_ops = {
447	474	.esp_write8 = mac_esp_write8,
448	475	.esp_read8 = mac_esp_read8,
...	...	@@ -557,10 +584,16 @@
557	584	}
558	585
559	586	host->irq = IRQ_MAC_SCSI;
560		- err = request_irq(host->irq, scsi_esp_intr, IRQF_SHARED, "Mac ESP",
561		- esp);
562		- if (err < 0)
563		- goto fail_free_priv;
	587	+ esp_chips[dev->id] = esp;
	588	+ mb();
	589	+ if (esp_chips[!dev->id] == NULL) {
	590	+ err = request_irq(host->irq, mac_scsi_esp_intr, 0,
	591	+ "Mac ESP", NULL);
	592	+ if (err < 0) {
	593	+ esp_chips[dev->id] = NULL;
	594	+ goto fail_free_priv;
	595	+ }
	596	+ }
564	597
565	598	err = scsi_esp_register(esp, &dev->dev);
566	599	if (err)
...	...	@@ -569,7 +602,8 @@
569	602	return 0;
570	603
571	604	fail_free_irq:
572		- free_irq(host->irq, esp);
	605	+ if (esp_chips[!dev->id] == NULL)
	606	+ free_irq(host->irq, esp);
573	607	fail_free_priv:
574	608	kfree(mep);
575	609	fail_free_command_block:
...	...	@@ -588,7 +622,9 @@
588	622
589	623	scsi_esp_unregister(esp);
590	624
591		- free_irq(irq, esp);
	625	+ esp_chips[dev->id] = NULL;
	626	+ if (!(esp_chips[0] \|\| esp_chips[1]))
	627	+ free_irq(irq, NULL);
592	628
593	629	kfree(mep);
594	630
595	631
596	632
...	...	@@ -615,19 +651,18 @@
615	651	if (err)
616	652	return err;
617	653
618		- internal_esp = platform_device_alloc(DRV_MODULE_NAME, 0);
619		- if (internal_esp && platform_device_add(internal_esp)) {
620		- platform_device_put(internal_esp);
621		- internal_esp = NULL;
	654	+ internal_pdev = platform_device_alloc(DRV_MODULE_NAME, 0);
	655	+ if (internal_pdev && platform_device_add(internal_pdev)) {
	656	+ platform_device_put(internal_pdev);
	657	+ internal_pdev = NULL;
622	658	}
623		-
624		- external_esp = platform_device_alloc(DRV_MODULE_NAME, 1);
625		- if (external_esp && platform_device_add(external_esp)) {
626		- platform_device_put(external_esp);
627		- external_esp = NULL;
	659	+ external_pdev = platform_device_alloc(DRV_MODULE_NAME, 1);
	660	+ if (external_pdev && platform_device_add(external_pdev)) {
	661	+ platform_device_put(external_pdev);
	662	+ external_pdev = NULL;
628	663	}
629	664
630		- if (internal_esp \|\| external_esp) {
	665	+ if (internal_pdev \|\| external_pdev) {
631	666	return 0;
632	667	} else {
633	668	platform_driver_unregister(&esp_mac_driver);
634	669
...	...	@@ -639,13 +674,13 @@
639	674	{
640	675	platform_driver_unregister(&esp_mac_driver);
641	676
642		- if (internal_esp) {
643		- platform_device_unregister(internal_esp);
644		- internal_esp = NULL;
	677	+ if (internal_pdev) {
	678	+ platform_device_unregister(internal_pdev);
	679	+ internal_pdev = NULL;
645	680	}
646		- if (external_esp) {
647		- platform_device_unregister(external_esp);
648		- external_esp = NULL;
	681	+ if (external_pdev) {
	682	+ platform_device_unregister(external_pdev);
	683	+ external_pdev = NULL;
649	684	}
650	685	}
651	686