MIPS: Add option to disable software I/O coherency.
Some MIPS controllers have hardware I/O coherency. This patch
detects those and turns off software coherency. A new kernel
command line option also allows the user to manually turn
software coherency on or off.
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
diff --git a/arch/mips/include/asm/dma-coherence.h b/arch/mips/include/asm/dma-coherence.h
new file mode 100644
index 0000000..242cbb3
--- /dev/null
+++ b/arch/mips/include/asm/dma-coherence.h
@@ -0,0 +1,15 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2006 Ralf Baechle <ralf@linux-mips.org>
+ *
+ */
+#ifndef __ASM_DMA_COHERENCE_H
+#define __ASM_DMA_COHERENCE_H
+
+extern int coherentio;
+extern int hw_coherentio;
+
+#endif
diff --git a/arch/mips/include/asm/dma-mapping.h b/arch/mips/include/asm/dma-mapping.h
index f8fc74b..84238c5 100644
--- a/arch/mips/include/asm/dma-mapping.h
+++ b/arch/mips/include/asm/dma-mapping.h
@@ -2,6 +2,7 @@
#define _ASM_DMA_MAPPING_H
#include <asm/scatterlist.h>
+#include <asm/dma-coherence.h>
#include <asm/cache.h>
#include <asm-generic/dma-coherent.h>
diff --git a/arch/mips/include/asm/mach-generic/dma-coherence.h b/arch/mips/include/asm/mach-generic/dma-coherence.h
index 9c95177..fe23034 100644
--- a/arch/mips/include/asm/mach-generic/dma-coherence.h
+++ b/arch/mips/include/asm/mach-generic/dma-coherence.h
@@ -61,9 +61,8 @@
{
#ifdef CONFIG_DMA_COHERENT
return 1;
-#endif
-#ifdef CONFIG_DMA_NONCOHERENT
- return 0;
+#else
+ return coherentio;
#endif
}
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 2078915..f5943ab 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -33,6 +33,7 @@
#include <asm/war.h>
#include <asm/cacheflush.h> /* for run_uncached() */
#include <asm/traps.h>
+#include <asm/dma-coherence.h>
/*
* Special Variant of smp_call_function for use by cache functions:
@@ -1377,20 +1378,6 @@
}
}
-#if defined(CONFIG_DMA_NONCOHERENT)
-
-static int __cpuinitdata coherentio;
-
-static int __init setcoherentio(char *str)
-{
- coherentio = 1;
-
- return 0;
-}
-
-early_param("coherentio", setcoherentio);
-#endif
-
static void __cpuinit r4k_cache_error_setup(void)
{
extern char __weak except_vec2_generic;
@@ -1472,9 +1459,14 @@
build_clear_page();
build_copy_page();
-#if !defined(CONFIG_MIPS_CMP)
+
+ /*
+ * We want to run CMP kernels on core with and without coherent
+ * caches. Therefore, do not use CONFIG_MIPS_CMP to decide whether
+ * or not to flush caches.
+ */
local_r4k___flush_cache_all(NULL);
-#endif
+
coherency_setup();
board_cache_error_setup = r4k_cache_error_setup;
}
diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index f9ef838..caf92ec 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -22,6 +22,26 @@
#include <dma-coherence.h>
+int coherentio = 0; /* User defined DMA coherency from command line. */
+EXPORT_SYMBOL_GPL(coherentio);
+int hw_coherentio = 0; /* Actual hardware supported DMA coherency setting. */
+
+static int __init setcoherentio(char *str)
+{
+ coherentio = 1;
+ pr_info("Hardware DMA cache coherency (command line)\n");
+ return 0;
+}
+early_param("coherentio", setcoherentio);
+
+static int __init setnocoherentio(char *str)
+{
+ coherentio = 0;
+ pr_info("Software DMA cache coherency (command line)\n");
+ return 0;
+}
+early_param("nocoherentio", setnocoherentio);
+
static inline struct page *dma_addr_to_page(struct device *dev,
dma_addr_t dma_addr)
{
@@ -115,7 +135,8 @@
if (!plat_device_is_coherent(dev)) {
dma_cache_wback_inv((unsigned long) ret, size);
- ret = UNCAC_ADDR(ret);
+ if (!hw_coherentio)
+ ret = UNCAC_ADDR(ret);
}
}
@@ -142,7 +163,7 @@
plat_unmap_dma_mem(dev, dma_handle, size, DMA_BIDIRECTIONAL);
- if (!plat_device_is_coherent(dev))
+ if (!plat_device_is_coherent(dev) && !hw_coherentio)
addr = CAC_ADDR(addr);
free_pages(addr, get_order(size));
diff --git a/arch/mips/mti-malta/malta-setup.c b/arch/mips/mti-malta/malta-setup.c
index 200f64d..a855571 100644
--- a/arch/mips/mti-malta/malta-setup.c
+++ b/arch/mips/mti-malta/malta-setup.c
@@ -32,6 +32,7 @@
#include <asm/mips-boards/maltaint.h>
#include <asm/dma.h>
#include <asm/traps.h>
+#include <asm/gcmpregs.h>
#ifdef CONFIG_VT
#include <linux/console.h>
#endif
@@ -105,6 +106,66 @@
}
#endif
+static int __init plat_enable_iocoherency(void)
+{
+ int supported = 0;
+ 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;
+ }
+ if (strstr(fw_getcmdline(), "iobcuncached")) {
+ BONITO_PCICACHECTRL &= ~BONITO_PCICACHECTRL_IOBCCOH_EN;
+ BONITO_PCIMEMBASECFG = BONITO_PCIMEMBASECFG &
+ ~(BONITO_PCIMEMBASECFG_MEMBASE0_CACHED |
+ BONITO_PCIMEMBASECFG_MEMBASE1_CACHED);
+ pr_info("Disabled Bonito IOBC coherency\n");
+ } else {
+ BONITO_PCICACHECTRL |= BONITO_PCICACHECTRL_IOBCCOH_EN;
+ BONITO_PCIMEMBASECFG |=
+ (BONITO_PCIMEMBASECFG_MEMBASE0_CACHED |
+ BONITO_PCIMEMBASECFG_MEMBASE1_CACHED);
+ pr_info("Enabled Bonito IOBC coherency\n");
+ }
+ } else if (gcmp_niocu() != 0) {
+ /* Nothing special needs to be done to enable coherency */
+ pr_info("CMP IOCU detected\n");
+ if ((*(unsigned int *)0xbf403000 & 0x81) != 0x81) {
+ 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)
+{
+#ifdef CONFIG_DMA_NONCOHERENT
+ /*
+ * Kernel has been configured with software coherency
+ * but we might choose to turn it off and use hardware
+ * coherency instead.
+ */
+ if (plat_enable_iocoherency()) {
+ if (coherentio == 0)
+ pr_info("Hardware DMA cache coherency disabled\n");
+ else
+ pr_info("Hardware DMA cache coherency enabled\n");
+ } else {
+ if (coherentio == 1)
+ pr_info("Hardware DMA cache coherency unsupported, but enabled from command line!\n");
+ else
+ pr_info("Software DMA cache coherency enabled\n");
+ }
+#else
+ if (!plat_enable_iocoherency())
+ panic("Hardware DMA cache coherency not supported!");
+#endif
+}
+
#ifdef CONFIG_BLK_DEV_IDE
static void __init pci_clock_check(void)
{
@@ -207,6 +268,8 @@
if (mips_revision_sconid == MIPS_REVISION_SCON_BONITO)
bonito_quirks_setup();
+ plat_setup_iocoherency();
+
#ifdef CONFIG_BLK_DEV_IDE
pci_clock_check();
#endif
diff --git a/arch/mips/mti-sead3/sead3-setup.c b/arch/mips/mti-sead3/sead3-setup.c
index f012fd1..14633bc 100644
--- a/arch/mips/mti-sead3/sead3-setup.c
+++ b/arch/mips/mti-sead3/sead3-setup.c
@@ -13,9 +13,6 @@
#include <asm/mips-boards/generic.h>
#include <asm/prom.h>
-int coherentio; /* 0 => no DMA cache coherency (may be set by user) */
-int hw_coherentio; /* 0 => no HW DMA cache coherency (reflects real HW) */
-
const char *get_system_type(void)
{
return "MIPS SEAD3";