MIPS: Alchemy: Default to noncoherent IO on Au1200 AB

CONFIG_DMA_COHERENT is no longer set; default to noncoherent io on
Au1200 revision AB to make USB work.
Signed-off-by: NManuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/6745/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/alchemy/common/setup.c

@@ -67,6 +67,12 @@ void __init plat_mem_setup(void)
 	case ALCHEMY_CPU_AU1500:
 	case ALCHEMY_CPU_AU1100:
 		coherentio = 0;
+		break;
+	case ALCHEMY_CPU_AU1200:
+		/* Au1200 AB USB does not support coherent memory */
+		if (0 == (read_c0_prid() & PRID_REV_MASK))
+			coherentio = 0;
+		break;
 	}
 
 	board_setup();	/* board specific setup */

arch/mips/alchemy/common/usb.c

@@ -355,47 +355,25 @@ static inline void __au1200_udc_control(void __iomem *base, int enable)
 	}
 }
 
-static inline int au1200_coherency_bug(void)
-{
-#if defined(CONFIG_DMA_COHERENT)
-	/* Au1200 AB USB does not support coherent memory */
-	if (!(read_c0_prid() & PRID_REV_MASK)) {
-		printk(KERN_INFO "Au1200 USB: this is chip revision AB !!\n");
-		printk(KERN_INFO "Au1200 USB: update your board or re-configure"
-				 " the kernel\n");
-		return -ENODEV;
-	}
-#endif
-	return 0;
-}
-
 static inline int au1200_usb_control(int block, int enable)
 {
 	void __iomem *base =
 			(void __iomem *)KSEG1ADDR(AU1200_USB_CTL_PHYS_ADDR);
-	int ret = 0;
 
 	switch (block) {
 	case ALCHEMY_USB_OHCI0:
-		ret = au1200_coherency_bug();
-		if (ret && enable)
-			goto out;
 		__au1200_ohci_control(base, enable);
 		break;
 	case ALCHEMY_USB_UDC0:
 		__au1200_udc_control(base, enable);
 		break;
 	case ALCHEMY_USB_EHCI0:
-		ret = au1200_coherency_bug();
-		if (ret && enable)
-			goto out;
 		__au1200_ehci_control(base, enable);
 		break;
 	default:
-		ret = -ENODEV;
+		return -ENODEV;
 	}
-out:
-	return ret;
+	return 0;
 }