MIPS/malta: simplify plat_setup_iocoherency

Given that plat_mem_setup runs before earlyparams are handled and malta
selects CONFIG_DMA_MAYBE_COHERENT, coherentio can only be set to
IO_COHERENCE_DEFAULT at this point.  So remove the checking for other
options and merge plat_enable_iocoherency into plat_setup_iocoherency
to simplify the code a bit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Author: Christoph Hellwig

arch/mips/mti-malta/malta-setup.c

@@ -90,16 +90,15 @@ static void __init fd_activate(void)
 }
 #endif
 
-static int __init plat_enable_iocoherency(void)
+static void __init plat_setup_iocoherency(void)
 {
-	int supported = 0;
 	u32 cfg;
 
 	if (mips_revision_sconid == MIPS_REVISION_SCON_BONITO) {
 		if (BONITO_PCICACHECTRL & BONITO_PCICACHECTRL_CPUCOH_PRES) {
 			BONITO_PCICACHECTRL |= BONITO_PCICACHECTRL_CPUCOH_EN;
 			pr_info("Enabled Bonito CPU coherency\n");
-			supported = 1;
+			hw_coherentio = 1;
 		}
 		if (strstr(fw_getcmdline(), "iobcuncached")) {
 			BONITO_PCICACHECTRL &= ~BONITO_PCICACHECTRL_IOBCCOH_EN;
@@ -118,29 +117,16 @@ static int __init plat_enable_iocoherency(void)
 		/* Nothing special needs to be done to enable coherency */
 		pr_info("CMP IOCU detected\n");
 		cfg = __raw_readl((u32 *)CKSEG1ADDR(ROCIT_CONFIG_GEN0));
-		if (!(cfg & ROCIT_CONFIG_GEN0_PCI_IOCU)) {
+		if (cfg & ROCIT_CONFIG_GEN0_PCI_IOCU)
+			hw_coherentio = 1;
+		else
 			pr_crit("IOCU OPERATION DISABLED BY SWITCH - DEFAULTING TO SW IO COHERENCY\n");
-			return 0;
-		}
-		supported = 1;
 	}
-	hw_coherentio = supported;
-	return supported;
-}
 
-static void __init plat_setup_iocoherency(void)
-{
-	if (plat_enable_iocoherency()) {
-		if (coherentio == IO_COHERENCE_DISABLED)
-			pr_info("Hardware DMA cache coherency disabled\n");
-		else
-			pr_info("Hardware DMA cache coherency enabled\n");
-	} else {
-		if (coherentio == IO_COHERENCE_ENABLED)
-			pr_info("Hardware DMA cache coherency unsupported, but enabled from command line!\n");
-		else
-			pr_info("Software DMA cache coherency enabled\n");
-	}
+	if (hw_coherentio)
+		pr_info("Hardware DMA cache coherency enabled\n");
+	else
+		pr_info("Software DMA cache coherency enabled\n");
 }
 
 static void __init pci_clock_check(void)