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 (file)
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 f8fc74b6cb47430b540d072833d62872192349d8..84238c574d5e6bff1db1db79d58a5ddbd4436422 100644 (file)
--- 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 9c95177f7a7e04bde7771cf5b7c8204753a57e9b..fe23034aaf721497af158ee2deec840038478dcf 100644 (file)
--- a/arch/mips/include/asm/mach-generic/dma-coherence.h
+++ b/arch/mips/include/asm/mach-generic/dma-coherence.h
@@ -61,9 +61,8 @@ static inline int plat_device_is_coherent(struct device *dev)
 {
 #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 2078915eacb9c9ff740ec2daa1a65274ad1de7a9..f5943ab44987f0d59dab3755e7b57e24544bf123 100644 (file)
--- 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 @@ static void __cpuinit coherency_setup(void)
        }
 }
 
-#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 @@ void __cpuinit r4k_cache_init(void)
 
        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 f9ef83829a523fd65803b3f5b2c8fdfe77e31a8f..caf92ecb37d6966639c47e6eb277d74cb42f2012 100644 (file)
--- 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 @@ static void *mips_dma_alloc_coherent(struct device *dev, size_t size,
 
                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 @@ static void mips_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
 
        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 200f64df2c9b492bf6ec948ff03bbfee864f59fa..a85557171faa2128ec99b8d4e469299ee44c0fff 100644 (file)
--- 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 @@ static void __init fd_activate(void)
 }
 #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 @@ void __init plat_mem_setup(void)
        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 f012fd164ceedc9e2aed9a94ebb30cc2bdc602c2..14633bc8004915796953555fa2bce76d0f8e7ba2 100644 (file)
--- 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";