From: "Steven J. Hill" <sjhill@xxxxxxxx>
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 <sjhill@xxxxxxxx>
---
arch/mips/include/asm/mach-generic/dma-coherence.h | 5 +-
arch/mips/mm/c-r4k.c | 34 +++++++---
arch/mips/mm/dma-default.c | 6 +-
arch/mips/mti-malta/malta-setup.c | 71 ++++++++++++++++++++
4 files changed, 105 insertions(+), 11 deletions(-)
diff --git a/arch/mips/include/asm/mach-generic/dma-coherence.h b/arch/mips/include/asm/mach-generic/dma-coherence.h
index 9c95177..cd17f22 100644
--- a/arch/mips/include/asm/mach-generic/dma-coherence.h
+++ b/arch/mips/include/asm/mach-generic/dma-coherence.h
@@ -57,13 +57,16 @@ static inline int plat_dma_mapping_error(struct device *dev,
return 0;
}
+extern int coherentio;
+extern int hw_coherentio;
+
static inline int plat_device_is_coherent(struct device *dev)
{
#ifdef CONFIG_DMA_COHERENT
return 1;
#endif
#ifdef CONFIG_DMA_NONCOHERENT
- return 0;
+ return coherentio;
#endif
}
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 606e828..e4ee358 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -1379,19 +1379,34 @@ static void __cpuinit coherency_setup(void)
}
}
-#if defined(CONFIG_DMA_NONCOHERENT)
-
-static int __cpuinitdata coherentio;
+int coherentio = 0; /* no DMA cache coherency (may be set by user) */
+int hw_coherentio = 0; /* no HW DMA cache coherency (reflects real HW) */
static int __init setcoherentio(char *str)
{
- coherentio = 1;
+ if (coherentio == 0)
+ pr_info("Command line enabling coherentio"
+ " (this will break...)!!\n");
+ coherentio = 1;
+ pr_info("Hardware DMA cache coherency (command line)\n");
return 0;
}
-
early_param("coherentio", setcoherentio);
-#endif
+
+static int __init setnocoherentio(char *str)
+{
+ if (coherentio < 0)
+ pr_info("Command line checking done before"
+ " plat_setup_iocoherency!!\n");
+ if (coherentio == 1)
+ pr_info("Command line disabling coherentio\n");
+
+ coherentio = 0;
+ pr_info("Software DMA cache coherency (command line)\n");
+ return 0;
+}
+early_param("nocoherentio", setnocoherentio);
static void __cpuinit r4k_cache_error_setup(void)
{
@@ -1415,6 +1430,7 @@ void __cpuinit r4k_cache_init(void)
{
extern void build_clear_page(void);
extern void build_copy_page(void);
+ extern int coherentio;
struct cpuinfo_mips *c = ¤t_cpu_data;
probe_pcache();
@@ -1474,9 +1490,11 @@ 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(s) with and without coherent caches */
+ /* Therefore can't use CONFIG_MIPS_CMP to decide to flush cache */
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 3fab204..aad5f7e 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -115,7 +115,8 @@ 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);
}
}
@@ -143,7 +144,8 @@ 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))
- addr = CAC_ADDR(addr);
+ if (!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 ed68073..4187102 100644
--- a/arch/mips/mti-malta/malta-setup.c
+++ b/arch/mips/mti-malta/malta-setup.c
@@ -31,6 +31,7 @@
#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
@@ -104,6 +105,74 @@ 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
+ */
+ if (plat_enable_iocoherency()) {
+ if (coherentio == 0)
+ pr_info("Hardware DMA cache coherency supported"
+ " but disabled from command line\n");
+ else {
+ coherentio = 1;
+ printk(KERN_INFO "Hardware DMA cache coherency\n");
+ }
+ } else {
+ if (coherentio == 1)
+ pr_info("Hardware DMA cache coherency not supported"
+ " but enabled from command line\n");
+ else {
+ coherentio = 0;
+ pr_info("Software DMA cache coherency\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)
{
@@ -205,6 +274,8 @@ 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
--
1.7.9.5
