LEON only needs snooping when DMA accesses are not seen on the processor
bus. Given that coherent allocations are mapped uncached this can't
happen for those, so open code the d-cache flushing logic in the only
remaing place that needs it, arch_sync_dma_for_cpu.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/sparc/kernel/ioport.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)
diff --git a/arch/sparc/kernel/ioport.c b/arch/sparc/kernel/ioport.c
index 7ceae24b0ca99..3eb748e862220 100644
--- a/arch/sparc/kernel/ioport.c
+++ b/arch/sparc/kernel/ioport.c
@@ -52,17 +52,6 @@
#include <asm/io-unit.h>
#include <asm/leon.h>
-/* This function must make sure that caches and memory are coherent after DMA
- * On LEON systems without cache snooping it flushes the entire D-CACHE.
- */
-static inline void dma_make_coherent(unsigned long pa, unsigned long len)
-{
- if (sparc_cpu_model == sparc_leon) {
- if (!sparc_leon3_snooping_enabled())
- leon_flush_dcache_all();
- }
-}
-
static void __iomem *_sparc_ioremap(struct resource *res, u32 bus, u32 pa, int sz);
static void __iomem *_sparc_alloc_io(unsigned int busno, unsigned long phys,
unsigned long size, char *name);
@@ -361,18 +350,23 @@ void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
if (!sparc_dma_free_resource(cpu_addr, size))
return;
- dma_make_coherent(dma_addr, size);
srmmu_unmapiorange((unsigned long)cpu_addr, size);
free_pages((unsigned long)phys_to_virt(dma_addr), get_order(size));
}
-/* IIep is write-through, not flushing on cpu to device transfer. */
-
+/*
+ * IIep is write-through, not flushing on cpu to device transfer.
+ *
+ * On LEON systems without cache snooping, the entire D-CACHE must be flushed to
+ * make DMA to cacheable memory coherent.
+ */
void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
- if (dir != PCI_DMA_TODEVICE)
- dma_make_coherent(paddr, PAGE_ALIGN(size));
+ if (dir != PCI_DMA_TODEVICE &&
+ sparc_cpu_model == sparc_leon &&
+ !sparc_leon3_snooping_enabled())
+ leon_flush_dcache_all();
}
#ifdef CONFIG_PROC_FS
--
2.30.2
