Patch to disable PCI coherency on AU1500 platforms

[Hartvig Ekner <hartvig@ekner.info>]

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The patch below sets the NC bit in the PCI_CFG register to disable HW coherency when
running non-coherent. Until now, this bit was cleared which means corruption when using PCI
DMA masters, even if the kernel was correctly compiled with CONFIG_NONCOHERENT_IO.

Pb1500 specific notes: I don't have a PB1500, so I cannot test if it works there. Note: I also
removed what I think was an extraneous write to the PCI_CMEM register, so if somebody
could test this on a PB1500 it would be great.

/Hartvig



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Index: db1x00/setup.c
===================================================================
RCS file: /home/cvs/linux/arch/mips/au1000/db1x00/Attic/setup.c,v
retrieving revision 1.1.2.4
diff -u -r1.1.2.4 setup.c
--- db1x00/setup.c	21 Mar 2003 19:00:46 -0000	1.1.2.4
+++ db1x00/setup.c	1 Apr 2003 12:14:54 -0000
@@ -78,9 +78,8 @@
 void __init au1x00_setup(void)
 {
 	char *argptr;
-	u32 pin_func, static_cfg0;
-	u32 sys_freqctrl, sys_clksrc;
-	u32 prid = read_c0_prid();
+	u32 pin_func;
+//	u32 prid = read_c0_prid();
 
 	argptr = prom_getcmdline();
 
@@ -187,6 +186,19 @@
 
 #ifdef CONFIG_BLK_DEV_IDE
 	ide_ops = &std_ide_ops;
+#endif
+
+#ifdef CONFIG_PCI
+	/* Although YAMON has setup the PCI controller, some things
+	   may need to change. Eventually, all the PCI initialization
+	   should be done here (as in eg. ../pb1500/setup.c)
+	*/
+
+#ifdef CONFIG_NONCOHERENT_IO
+	/* Must disable PCI coherency if running non-coherent */
+
+	au_writel(au_readl(Au1500_PCI_CFG) | (1<<16), Au1500_PCI_CFG);
+#endif
 #endif
 
 #if 0
Index: pb1500/setup.c
===================================================================
RCS file: /home/cvs/linux/arch/mips/au1000/pb1500/setup.c,v
retrieving revision 1.1.2.12
diff -u -r1.1.2.12 setup.c
--- pb1500/setup.c	21 Mar 2003 19:00:47 -0000	1.1.2.12
+++ pb1500/setup.c	1 Apr 2003 12:14:54 -0000
@@ -35,6 +35,7 @@
 #include <linux/console.h>
 #include <linux/mc146818rtc.h>
 #include <linux/delay.h>
+#include <linux/proc_fs.h>
 
 #include <asm/cpu.h>
 #include <asm/bootinfo.h>
@@ -90,6 +91,7 @@
 	char *argptr;
 	u32 pin_func, static_cfg0;
 	u32 sys_freqctrl, sys_clksrc;
+	u32 pcicfg;
 
 	argptr = prom_getcmdline();
 
@@ -232,15 +234,25 @@
 
 #ifdef CONFIG_PCI
 	// Setup PCI bus controller
-	au_writel(0, Au1500_PCI_CMEM);
-	au_writel(0x00003fff, Au1500_CFG_BASE);
+
+	au_writel(0x00003fff, Au1500_PCI_CMEM);
+
 #if defined(__MIPSEB__)
-	au_writel(0xf | (2<<6) | (1<<4), Au1500_PCI_CFG);
+	pcicfg = 0xf | (2<<6) | (1<<4);
 #else
-	au_writel(0xf, Au1500_PCI_CFG);
+	pcicfg = 0xf;
 #endif
+
+#ifdef CONFIG_NONCOHERENT_IO
+	/* Must disable PCI coherency if running non-coherent */
+
+	pcicfg |= (1<<16);
+#endif
+
+	au_writel(pcicfg,     Au1500_PCI_CFG);
+
 	au_writel(0xf0000000, Au1500_PCI_MWMASK_DEV);
-	au_writel(0, Au1500_PCI_MWBASE_REV_CCL);
+	au_writel(0,          Au1500_PCI_MWBASE_REV_CCL);
 	au_writel(0x02a00356, Au1500_PCI_STATCMD);
 	au_writel(0x00003c04, Au1500_PCI_HDRTYPE);
 	au_writel(0x00000008, Au1500_PCI_MBAR);