[PATCH] 2.5.3 ISDN work around buggy hw

the appended patch works around a bug in the PLX9050 chip. This chip is
used in various PCI ISDN adapters (it's an PCI interface chip) and has
an erratum when the BAR 0/1 has bit 7 set (the size of the region is
0x80, so aligning it to 0x80 is legal and really happens for people).

This workaround has been tested by a user who hit this problem with a
Gazel card. Basically the same fix has been done for Elsa cards, but it's
untested.

drivers/isdn/hisax/elsa.c

@@ -396,7 +396,8 @@ elsa_interrupt_ipac(int intno, void *dev_id, struct pt_regs *regs)
 	}
 	if (cs->subtyp == ELSA_QS1000PCI || cs->subtyp == ELSA_QS3000PCI) {
 		val = bytein(cs->hw.elsa.cfg + 0x4c); /* PCI IRQ */
-		if (!(val & ELSA_PCI_IRQ_MASK))
+		if (!test_bit(FLG_BUGGY_PLX9050, &cs->HW_Flags) && 
+		    !(val & ELSA_PCI_IRQ_MASK))
 			return;
 	}
 #if ARCOFI_USE
@@ -868,7 +869,7 @@ setup_elsa(struct IsdnCard *card)
 {
 	long flags;
 	int bytecnt;
-	u_char val;
+	u_char val, pci_rev;
 	struct IsdnCardState *cs = card->cs;
 	char tmp[64];
 
@@ -992,6 +993,7 @@ setup_elsa(struct IsdnCard *card)
 			cs->irq = dev_qs1000->irq;
 			cs->hw.elsa.cfg = pci_resource_start(dev_qs1000, 1);
 			cs->hw.elsa.base = pci_resource_start(dev_qs1000, 3);
+			pci_read_config_byte(dev_qs1000, PCI_REVISION_ID, &pci_rev);
 		} else if ((dev_qs3000 = pci_find_device(PCI_VENDOR_ID_ELSA,
 			PCI_DEVICE_ID_ELSA_QS3000, dev_qs3000))) {
 			if (pci_enable_device(dev_qs3000))
@@ -1000,6 +1002,7 @@ setup_elsa(struct IsdnCard *card)
 			cs->irq = dev_qs3000->irq;
 			cs->hw.elsa.cfg = pci_resource_start(dev_qs3000, 1);
 			cs->hw.elsa.base = pci_resource_start(dev_qs3000, 3);
+			pci_read_config_byte(dev_qs1000, PCI_REVISION_ID, &pci_rev);
 		} else {
 			printk(KERN_WARNING "Elsa: No PCI card found\n");
 			return(0);
@@ -1013,15 +1016,9 @@ setup_elsa(struct IsdnCard *card)
 			printk(KERN_WARNING "Elsa: No IO-Adr for PCI card found\n");
 			return(0);
 		}
-		if ((cs->hw.elsa.cfg & 0xff) || (cs->hw.elsa.base & 0xf)) {
-			printk(KERN_WARNING "Elsa: You may have a wrong PCI bios\n");
-			printk(KERN_WARNING "Elsa: If your system hangs now, read\n");
-			printk(KERN_WARNING "Elsa: Documentation/isdn/README.HiSax\n");
-			printk(KERN_WARNING "Elsa: Waiting 5 sec to sync discs\n");
-			save_flags(flags);
-			sti();
-			HZDELAY(500);	/* wait 500*10 ms */
-			restore_flags(flags);
+		if (cs->hw.elsa.cfg & 0x80 && pci_rev == 1) {
+			printk(KERN_INFO "Elsa: PLX9050 rev1 workaround activated");
+			set_bit(FLG_BUGGY_PLX9050, &cs->HW_Flags);
 		}
 		cs->hw.elsa.ale  = cs->hw.elsa.base;
 		cs->hw.elsa.isac = cs->hw.elsa.base +1;

drivers/isdn/hisax/gazel.c

@@ -382,12 +382,16 @@ reset_gazel(struct IsdnCardState *cs)
 			outb(INT_ISAC_EN + INT_HSCX_EN + INT_PCI_EN, addr + PLX_INCSR);
 			break;
 		case R753:
-			plxcntrl = inl(addr + PLX_CNTRL);
+			if (test_bit(FLG_BUGGY_PLX9050, &cs->HW_Flags))
+				/* we can't read, assume the default */
+				plxcntrl = 0x18784db6;
+			else
+				plxcntrl = inl(addr + PLX_CNTRL);
 			plxcntrl |= (RESET_9050 + RESET_GAZEL);
 			outl(plxcntrl, addr + PLX_CNTRL);
-			plxcntrl &= ~(RESET_9050 + RESET_GAZEL);
 			WriteISAC(cs, IPAC_POTA2 - 0x80, 0x20);
 			HZDELAY(4);
+			plxcntrl &= ~(RESET_9050 + RESET_GAZEL);
 			outl(plxcntrl, addr + PLX_CNTRL);
 			HZDELAY(10);
 			WriteISAC(cs, IPAC_POTA2 - 0x80, 0x00);
@@ -549,6 +553,7 @@ setup_gazelpci(struct IsdnCardState *cs)
 	u_int pci_ioaddr0 = 0, pci_ioaddr1 = 0;
 	u_char pci_irq = 0, found;
 	u_int nbseek, seekcard;
+	u_char pci_rev;
 
 	printk(KERN_WARNING "Gazel: PCI card automatic recognition\n");
 
@@ -623,6 +628,18 @@ setup_gazelpci(struct IsdnCardState *cs)
 			printk(KERN_INFO
 			    "Gazel: config irq:%d ipac:0x%X  cfg:0x%X\n",
 			cs->irq, cs->hw.gazel.ipac, cs->hw.gazel.cfg_reg);
+			/* 
+			 * Erratum for PLX9050, revision 1:
+			 * If bit 7 of BAR 0/1 is set, local config registers
+			 * can not be read (write is okay)
+			 */
+			if (cs->hw.gazel.cfg_reg & 0x80) {
+				pci_read_config_byte(dev_tel, PCI_REVISION_ID, &pci_rev);
+				if (pci_rev == 1) {
+					printk(KERN_INFO "Gazel: PLX9050 rev1 workaround activated");
+					set_bit(FLG_BUGGY_PLX9050, &cs->HW_Flags);
+				}
+			}
 			break;
 	}
 

drivers/isdn/hisax/hisax.h

@@ -859,6 +859,7 @@ struct icc_chip {
 #define FLG_ARCOFI_TIMER	8
 #define FLG_ARCOFI_ERROR	9
 #define FLG_HW_L1_UINT		10
+#define FLG_BUGGY_PLX9050       11
 
 struct IsdnCardState {
 	unsigned char typ;