openwrt/target/linux/xburst/patches-3.10/013-MIPS-JZ4740-Acquire-and-enable-DMA-controller-clock.patch

From b1ab71156cd49b2389397d3be54b93fe394a1cb2 Mon Sep 17 00:00:00 2001
From: Maarten ter Huurne <maarten@treewalker.org>
Date: Tue, 9 Oct 2012 13:09:57 +0200
Subject: [PATCH 13/16] MIPS: JZ4740: Acquire and enable DMA controller clock

Previously, it was assumed that the DMA controller clock is not gated
when the kernel starts running. While that is the power-on state, it is
safer to not rely on that.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
 arch/mips/jz4740/clock.c |    2 +-
 arch/mips/jz4740/dma.c   |   24 ++++++++++++++++++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

--- a/arch/mips/jz4740/clock.c
+++ b/arch/mips/jz4740/clock.c
@@ -921,4 +921,4 @@ static int jz4740_clock_init(void)
 
 	return 0;
 }
-arch_initcall(jz4740_clock_init);
+postcore_initcall(jz4740_clock_init);
--- a/arch/mips/jz4740/dma.c
+++ b/arch/mips/jz4740/dma.c
@@ -16,6 +16,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
+#include <linux/clk.h>
 #include <linux/interrupt.h>
 
 #include <linux/dma-mapping.h>
@@ -268,6 +269,7 @@ static irqreturn_t jz4740_dma_irq(int ir
 
 static int jz4740_dma_init(void)
 {
+	struct clk *clk;
 	unsigned int ret;
 
 	jz4740_dma_base = ioremap(JZ4740_DMAC_BASE_ADDR, 0x400);
@@ -277,11 +279,29 @@ static int jz4740_dma_init(void)
 
 	spin_lock_init(&jz4740_dma_lock);
 
-	ret = request_irq(JZ4740_IRQ_DMAC, jz4740_dma_irq, 0, "DMA", NULL);
+	clk = clk_get(NULL, "dma");
+	if (IS_ERR(clk)) {
+		ret = PTR_ERR(clk);
+		printk(KERN_ERR "JZ4740 DMA: Failed to request clock: %d\n",
+				ret);
+		goto err_iounmap;
+	}
 
-	if (ret)
+	ret = request_irq(JZ4740_IRQ_DMAC, jz4740_dma_irq, 0, "DMA", NULL);
+	if (ret) {
 		printk(KERN_ERR "JZ4740 DMA: Failed to request irq: %d\n", ret);
+		goto err_clkput;
+	}
+
+	clk_enable(clk);
+
+	return 0;
+
+err_clkput:
+	clk_put(clk);
 
+err_iounmap:
+	iounmap(jz4740_dma_base);
 	return ret;
 }
 arch_initcall(jz4740_dma_init);