[PATCH 09/13] mtd: nand: pxa3xx: Make dma code dependent on dma capable platforms

Ezequiel Garcia
2013-07-29T23:25:27Z

This patch adds a macro ARCH_HAS_DMA to compile-out arch specific
dma code, namely pxa_request_dma() and pxa_free_dma(). These symbols
are available only in pxa, which makes impossible to build the driver in
other platforms than ARCH_PXA.

In order to handle non-dma capable platforms, we implement a fallbacks that
allocate buffers as if 'use_dma=false', putting the dma related code
under the ARCH_HAS_DMA conditional.

Please note that the correct way to handle this is to migrate the
dma code to use of the mmp_pdma dmaengine driver. However, currently
this is not possible because the two dmaengine drivers can't work together.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
---
drivers/mtd/nand/pxa3xx_nand.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)

diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
index 3b0b456..03346e9 100644
--- a/drivers/mtd/nand/pxa3xx_nand.c
+++ b/drivers/mtd/nand/pxa3xx_nand.c
@@ -25,7 +25,14 @@
#include <linux/of.h>
#include <linux/of_device.h>

+#if defined(CONFIG_ARCH_PXA) || defined(CONFIG_ARCH_MMP)
+#define ARCH_HAS_DMA
+#endif
+
+#ifdef ARCH_HAS_DMA
#include <mach/dma.h>
+#endif
+
#include <linux/platform_data/mtd-nand-pxa3xx.h>

#define CHIP_DELAY_TIMEOUT (2 * HZ/10)
@@ -370,6 +377,7 @@ static void handle_data_pio(struct pxa3xx_nand_info *info)
}
}

+#ifdef ARCH_HAS_DMA
static void start_data_dma(struct pxa3xx_nand_info *info)
{
struct pxa_dma_desc *desc = info->data_desc;
@@ -416,6 +424,10 @@ static void pxa3xx_nand_data_dma_irq(int channel, void *data)
enable_int(info, NDCR_INT_MASK);
nand_writel(info, NDSR, NDSR_WRDREQ | NDSR_RDDREQ);
}
+#else
+static void start_data_dma(struct pxa3xx_nand_info *info)
+{}
+#endif

static irqreturn_t pxa3xx_nand_irq(int irq, void *devid)
{
@@ -882,6 +894,7 @@ static int pxa3xx_nand_detect_config(struct pxa3xx_nand_info *info)
*/
#define MAX_BUFF_SIZE PAGE_SIZE

+#ifdef ARCH_HAS_DMA
static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
{
struct platform_device *pdev = info->pdev;
@@ -927,6 +940,20 @@ static void pxa3xx_nand_free_buff(struct pxa3xx_nand_info *info)
kfree(info->data_buff);
}
}
+#else
+static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
+{
+ info->data_buff = kmalloc(MAX_BUFF_SIZE, GFP_KERNEL);
+ if (info->data_buff == NULL)
+ return -ENOMEM;
+ return 0;
+}
+
+static void pxa3xx_nand_free_buff(struct pxa3xx_nand_info *info)
+{
+ kfree(info->data_buff);
+}
+#endif

static int pxa3xx_nand_sensing(struct pxa3xx_nand_info *info)
{
@@ -1225,6 +1252,14 @@ static int pxa3xx_nand_probe(struct platform_device *pdev)
struct pxa3xx_nand_info *info;
int ret, cs, probe_success;

+#ifndef ARCH_HAS_DMA
+ if (use_dma) {
+ use_dma = 0;
+ dev_warn(&pdev->dev,
+ "This platform can't do DMA on this device\n");
+ }
+#endif
+
ret = pxa3xx_nand_probe_dt(pdev);
if (ret)
return ret;
--
1.8.1.5