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>

diff --git a/arch/mips/jz4740/dma.c b/arch/mips/jz4740/dma.c
index 317ec6f..0e34b97 100644 (file)
--- 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);