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: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 22 insertions, 2 deletions

diff --git a/arch/mips/jz4740/dma.c b/arch/mips/jz4740/dma.c
index 317ec6fffb12..0e34b97efa8c 100644
--- 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 irq, void *dev_id)
 
 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_prepare_enable(clk);
+
+        return 0;
+
+err_clkput:
+        clk_put(clk);
 
+err_iounmap:
+        iounmap(jz4740_dma_base);
         return ret;
 }
 arch_initcall(jz4740_dma_init);