These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

1 files changed, 36 insertions, 10 deletions

diff --git a/kernel/arch/arc/mm/dma.c b/kernel/arch/arc/mm/dma.c
index 12cc6485b..29a46bb19 100644
--- a/kernel/arch/arc/mm/dma.c
+++ b/kernel/arch/arc/mm/dma.c
@@ -14,13 +14,12 @@
  * Cache bit off in the TLB entry.
  *
  * The default DMA address == Phy address which is 0x8000_0000 based.
- * A platform/device can make it zero based, by over-riding
- * plat_{dma,kernel}_addr_to_{kernel,dma}
  */
 
 #include <linux/dma-mapping.h>
 #include <linux/dma-debug.h>
 #include <linux/export.h>
+#include <asm/cache.h>
 #include <asm/cacheflush.h>
 
 /*
@@ -37,7 +36,7 @@ void *dma_alloc_noncoherent(struct device *dev, size_t size,
 		return NULL;
 
 	/* This is bus address, platform dependent */
-	*dma_handle = plat_kernel_addr_to_dma(dev, paddr);
+	*dma_handle = (dma_addr_t)paddr;
 
 	return paddr;
 }
@@ -46,8 +45,7 @@ EXPORT_SYMBOL(dma_alloc_noncoherent);
 void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
 			  dma_addr_t dma_handle)
 {
-	free_pages_exact((void *)plat_dma_addr_to_kernel(dev, dma_handle),
-			 size);
+	free_pages_exact((void *)dma_handle, size);
 }
 EXPORT_SYMBOL(dma_free_noncoherent);
 
@@ -56,6 +54,20 @@ void *dma_alloc_coherent(struct device *dev, size_t size,
 {
 	void *paddr, *kvaddr;
 
+	/*
+	 * IOC relies on all data (even coherent DMA data) being in cache
+	 * Thus allocate normal cached memory
+	 *
+	 * The gains with IOC are two pronged:
+	 *   -For streaming data, elides needs for cache maintenance, saving
+	 *    cycles in flush code, and bus bandwidth as all the lines of a
+	 *    buffer need to be flushed out to memory
+	 *   -For coherent data, Read/Write to buffers terminate early in cache
+	 *   (vs. always going to memory - thus are faster)
+	 */
+	if (is_isa_arcv2() && ioc_exists)
+		return dma_alloc_noncoherent(dev, size, dma_handle, gfp);
+
 	/* This is linear addr (0x8000_0000 based) */
 	paddr = alloc_pages_exact(size, gfp);
 	if (!paddr)
@@ -63,11 +75,23 @@ void *dma_alloc_coherent(struct device *dev, size_t size,
 
 	/* This is kernel Virtual address (0x7000_0000 based) */
 	kvaddr = ioremap_nocache((unsigned long)paddr, size);
-	if (kvaddr != NULL)
-		memset(kvaddr, 0, size);
+	if (kvaddr == NULL)
+		return NULL;
 
 	/* This is bus address, platform dependent */
-	*dma_handle = plat_kernel_addr_to_dma(dev, paddr);
+	*dma_handle = (dma_addr_t)paddr;
+
+	/*
+	 * Evict any existing L1 and/or L2 lines for the backing page
+	 * in case it was used earlier as a normal "cached" page.
+	 * Yeah this bit us - STAR 9000898266
+	 *
+	 * Although core does call flush_cache_vmap(), it gets kvaddr hence
+	 * can't be used to efficiently flush L1 and/or L2 which need paddr
+	 * Currently flush_cache_vmap nukes the L1 cache completely which
+	 * will be optimized as a separate commit
+	 */
+	dma_cache_wback_inv((unsigned long)paddr, size);
 
 	return kvaddr;
 }
@@ -76,10 +100,12 @@ EXPORT_SYMBOL(dma_alloc_coherent);
 void dma_free_coherent(struct device *dev, size_t size, void *kvaddr,
 		       dma_addr_t dma_handle)
 {
+	if (is_isa_arcv2() && ioc_exists)
+		return dma_free_noncoherent(dev, size, kvaddr, dma_handle);
+
 	iounmap((void __force __iomem *)kvaddr);
 
-	free_pages_exact((void *)plat_dma_addr_to_kernel(dev, dma_handle),
-			 size);
+	free_pages_exact((void *)dma_handle, size);
 }
 EXPORT_SYMBOL(dma_free_coherent);