[PATCH v2] MIPS: Alchemy: Default to noncoherent IO on Au1200 AB

[Manuel Lauss <manuel.lauss@xxxxxxxxx>]

CONFIG_DMA_COHERENT is no longer set; default to noncoherent io on
Au1200 revision AB to make USB work.

Signed-off-by: Manuel Lauss <manuel.lauss@xxxxxxxxx>
---
v2: Ralf made me aware that only enabling this quirk when USB is compiled
    in is flawed since someone might load a newly-compiled USB stack into
    a non-usb aware kernel.

 arch/mips/alchemy/common/setup.c |  6 ++++++
 arch/mips/alchemy/common/usb.c   | 26 ++------------------------
 2 files changed, 8 insertions(+), 24 deletions(-)

diff --git a/arch/mips/alchemy/common/setup.c b/arch/mips/alchemy/common/setup.c
index 566a174..8267e3c 100644
--- a/arch/mips/alchemy/common/setup.c
+++ b/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 */
diff --git a/arch/mips/alchemy/common/usb.c b/arch/mips/alchemy/common/usb.c
index 2adc7ed..d193dbe 100644
--- a/arch/mips/alchemy/common/usb.c
+++ b/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;
 }
 
 
-- 
1.9.1