Merge tag 'xtensa-20161219' of git://github.com/jcmvbkbc/linux-xtensa

Pull Xtensa updates from Max Filippov:

 - enable HAVE_DMA_CONTIGUOUS, configure shared DMA pool reservation in
   kc705 DTS

 - update xtensa DMA-related Documentation/features entries

 - clean up arch/xtensa/kernel/setup.c: move S32C1I self-test out of it,
   remove unused declarations, fix screen_info definition

* tag 'xtensa-20161219' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: update DMA-related Documentation/features entries
  xtensa: configure shared DMA pool reservation in kc705 DTS
  xtensa: enable HAVE_DMA_CONTIGUOUS
  xtensa: move S32C1I self-test to a separate file
  xtensa: fix screen_info, clean up unused declarations in setup.c

Documentation/features/io/dma-api-debug/arch-support.txt

@@ -36,5 +36,5 @@
     |          um: | TODO |
     |   unicore32: | TODO |
     |         x86: |  ok  |
-    |      xtensa: | TODO |
+    |      xtensa: |  ok  |
     -----------------------

Documentation/features/io/dma-contiguous/arch-support.txt

@@ -36,5 +36,5 @@
     |          um: | TODO |
     |   unicore32: | TODO |
     |         x86: |  ok  |
-    |      xtensa: | TODO |
+    |      xtensa: |  ok  |
     -----------------------

arch/xtensa/Kconfig

@@ -15,6 +15,7 @@ config XTENSA
 	select GENERIC_SCHED_CLOCK
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_API_DEBUG
+	select HAVE_DMA_CONTIGUOUS
 	select HAVE_EXIT_THREAD
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUTEX_CMPXCHG if !MMU

arch/xtensa/boot/dts/kc705.dts

@@ -11,4 +11,20 @@
 		device_type = "memory";
 		reg = <0x00000000 0x38000000>;
 	};
+
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		/* global autoconfigured region for contiguous allocations */
+		linux,cma {
+			compatible = "shared-dma-pool";
+			reusable;
+			size = <0x04000000>;
+			alignment = <0x2000>;
+			alloc-ranges = <0x00000000 0x20000000>;
+			linux,cma-default;
+		};
+	};
 };

arch/xtensa/include/asm/Kbuild

@@ -3,6 +3,7 @@ generic-y += bug.h
 generic-y += clkdev.h
 generic-y += cputime.h
 generic-y += div64.h
+generic-y += dma-contiguous.h
 generic-y += emergency-restart.h
 generic-y += errno.h
 generic-y += exec.h

arch/xtensa/kernel/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_FUNCTION_TRACER) += mcount.o
 obj-$(CONFIG_SMP) += smp.o mxhead.o
 obj-$(CONFIG_XTENSA_VARIANT_HAVE_PERF_EVENTS) += perf_event.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
+obj-$(CONFIG_S32C1I_SELFTEST) += s32c1i_selftest.o
 
 AFLAGS_head.o += -mtext-section-literals
 AFLAGS_mxhead.o += -mtext-section-literals

arch/xtensa/kernel/pci-dma.c

@@ -15,6 +15,7 @@
  * Joe Taylor <[email protected], [email protected]>
  */
 
+#include <linux/dma-contiguous.h>
 #include <linux/gfp.h>
 #include <linux/highmem.h>
 #include <linux/mm.h>
@@ -146,18 +147,27 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
 {
 	unsigned long ret;
 	unsigned long uncached = 0;
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	struct page *page = NULL;
 
 	/* ignore region speicifiers */
 
 	flag &= ~(__GFP_DMA | __GFP_HIGHMEM);
 
 	if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
 		flag |= GFP_DMA;
-	ret = (unsigned long)__get_free_pages(flag, get_order(size));
 
-	if (ret == 0)
+	if (gfpflags_allow_blocking(flag))
+		page = dma_alloc_from_contiguous(dev, count, get_order(size));
+
+	if (!page)
+		page = alloc_pages(flag, get_order(size));
+
+	if (!page)
 		return NULL;
 
+	ret = (unsigned long)page_address(page);
+
 	/* We currently don't support coherent memory outside KSEG */
 
 	BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
@@ -170,16 +180,19 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
 	return (void *)uncached;
 }
 
-static void xtensa_dma_free(struct device *hwdev, size_t size, void *vaddr,
+static void xtensa_dma_free(struct device *dev, size_t size, void *vaddr,
 			    dma_addr_t dma_handle, unsigned long attrs)
 {
 	unsigned long addr = (unsigned long)vaddr +
 		XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
+	struct page *page = virt_to_page(addr);
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 
 	BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
 	       addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 
-	free_pages(addr, get_order(size));
+	if (!dma_release_from_contiguous(dev, page, count))
+		__free_pages(page, get_order(size));
 }
 
 static dma_addr_t xtensa_map_page(struct device *dev, struct page *page,

arch/xtensa/kernel/s32c1i_selftest.c

@@ -0,0 +1,128 @@
+/*
+ * S32C1I selftest.
+ *
+ * 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) 2016 Cadence Design Systems Inc.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+
+#include <asm/traps.h>
+
+#if XCHAL_HAVE_S32C1I
+
+static int __initdata rcw_word, rcw_probe_pc, rcw_exc;
+
+/*
+ * Basic atomic compare-and-swap, that records PC of S32C1I for probing.
+ *
+ * If *v == cmp, set *v = set.  Return previous *v.
+ */
+static inline int probed_compare_swap(int *v, int cmp, int set)
+{
+	int tmp;
+
+	__asm__ __volatile__(
+			"	movi	%1, 1f\n"
+			"	s32i	%1, %4, 0\n"
+			"	wsr	%2, scompare1\n"
+			"1:	s32c1i	%0, %3, 0\n"
+			: "=a" (set), "=&a" (tmp)
+			: "a" (cmp), "a" (v), "a" (&rcw_probe_pc), "0" (set)
+			: "memory"
+			);
+	return set;
+}
+
+/* Handle probed exception */
+
+static void __init do_probed_exception(struct pt_regs *regs,
+				       unsigned long exccause)
+{
+	if (regs->pc == rcw_probe_pc) {	/* exception on s32c1i ? */
+		regs->pc += 3;		/* skip the s32c1i instruction */
+		rcw_exc = exccause;
+	} else {
+		do_unhandled(regs, exccause);
+	}
+}
+
+/* Simple test of S32C1I (soc bringup assist) */
+
+static int __init check_s32c1i(void)
+{
+	int n, cause1, cause2;
+	void *handbus, *handdata, *handaddr; /* temporarily saved handlers */
+
+	rcw_probe_pc = 0;
+	handbus  = trap_set_handler(EXCCAUSE_LOAD_STORE_ERROR,
+			do_probed_exception);
+	handdata = trap_set_handler(EXCCAUSE_LOAD_STORE_DATA_ERROR,
+			do_probed_exception);
+	handaddr = trap_set_handler(EXCCAUSE_LOAD_STORE_ADDR_ERROR,
+			do_probed_exception);
+
+	/* First try an S32C1I that does not store: */
+	rcw_exc = 0;
+	rcw_word = 1;
+	n = probed_compare_swap(&rcw_word, 0, 2);
+	cause1 = rcw_exc;
+
+	/* took exception? */
+	if (cause1 != 0) {
+		/* unclean exception? */
+		if (n != 2 || rcw_word != 1)
+			panic("S32C1I exception error");
+	} else if (rcw_word != 1 || n != 1) {
+		panic("S32C1I compare error");
+	}
+
+	/* Then an S32C1I that stores: */
+	rcw_exc = 0;
+	rcw_word = 0x1234567;
+	n = probed_compare_swap(&rcw_word, 0x1234567, 0xabcde);
+	cause2 = rcw_exc;
+
+	if (cause2 != 0) {
+		/* unclean exception? */
+		if (n != 0xabcde || rcw_word != 0x1234567)
+			panic("S32C1I exception error (b)");
+	} else if (rcw_word != 0xabcde || n != 0x1234567) {
+		panic("S32C1I store error");
+	}
+
+	/* Verify consistency of exceptions: */
+	if (cause1 || cause2) {
+		pr_warn("S32C1I took exception %d, %d\n", cause1, cause2);
+		/* If emulation of S32C1I upon bus error gets implemented,
+		 * we can get rid of this panic for single core (not SMP)
+		 */
+		panic("S32C1I exceptions not currently supported");
+	}
+	if (cause1 != cause2)
+		panic("inconsistent S32C1I exceptions");
+
+	trap_set_handler(EXCCAUSE_LOAD_STORE_ERROR, handbus);
+	trap_set_handler(EXCCAUSE_LOAD_STORE_DATA_ERROR, handdata);
+	trap_set_handler(EXCCAUSE_LOAD_STORE_ADDR_ERROR, handaddr);
+	return 0;
+}
+
+#else /* XCHAL_HAVE_S32C1I */
+
+/* This condition should not occur with a commercially deployed processor.
+ * Display reminder for early engr test or demo chips / FPGA bitstreams
+ */
+static int __init check_s32c1i(void)
+{
+	pr_warn("Processor configuration lacks atomic compare-and-swap support!\n");
+	return 0;
+}
+
+#endif /* XCHAL_HAVE_S32C1I */
+
+early_initcall(check_s32c1i);