parisc: Don't enforce DMA completion order in cache flushes

The only place we need to ensure all outstanding cache coherence
operations are complete is in invalidate_kernel_vmap_range. All
parisc drivers synchronize DMA operations internally and do not
call invalidate_kernel_vmap_range. We only need this for non-coherent
I/O operations.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

Author: danglin44

arch/parisc/include/asm/cache.h

@@ -54,6 +54,7 @@ void parisc_setup_cache_timing(void);
 #define asm_io_sync()	asm volatile("sync" \
 			ALTERNATIVE(ALT_COND_NO_DCACHE, INSN_NOP) \
 			ALTERNATIVE(ALT_COND_NO_IOC_FDC, INSN_NOP) :::"memory")
+#define asm_syncdma()	asm volatile("syncdma" :::"memory")
 
 #endif /* ! __ASSEMBLY__ */
 

arch/parisc/kernel/cache.c

@@ -754,6 +754,9 @@ void invalidate_kernel_vmap_range(void *vaddr, int size)
 	unsigned long start = (unsigned long)vaddr;
 	unsigned long end = start + size;
 
+	/* Ensure DMA is complete */
+	asm_syncdma();
+
 	if ((!IS_ENABLED(CONFIG_SMP) || !arch_irqs_disabled()) &&
 	    (unsigned long)size >= parisc_cache_flush_threshold) {
 		flush_tlb_kernel_range(start, end);

arch/parisc/kernel/pacache.S

@@ -300,7 +300,6 @@ fdoneloop2:
 	fdce,m		%arg1(%sr1, %arg0)	/* Fdce for one loop */
 
 fdsync:
-	syncdma
 	sync
 	mtsm		%r22			/* restore I-bit */
 89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
@@ -1098,7 +1097,6 @@ ENTRY_CFI(flush_kernel_dcache_range_asm)
 
 	sync
 89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
-	syncdma
 	bv		%r0(%r2)
 	nop
 ENDPROC_CFI(flush_kernel_dcache_range_asm)
@@ -1140,7 +1138,6 @@ ENTRY_CFI(purge_kernel_dcache_range_asm)
 
 	sync
 89:	ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
-	syncdma
 	bv		%r0(%r2)
 	nop
 ENDPROC_CFI(purge_kernel_dcache_range_asm)