Re: [PATCH v3 4/7] of: configure the platform device dma parameters

Santosh Shilimkar
2014-05-05T21:48:10Z

On Thursday 01 May 2014 08:49 PM, Rob Herring wrote:
> On Thu, Apr 24, 2014 at 10:30 AM, Santosh Shilimkar
> <santosh.shilimkar@ti.com> wrote:
>> Retrieve DMA configuration from DT and setup platform device's DMA
>> parameters. The DMA configuration in DT has to be specified using
>> "dma-ranges" and "dma-coherent" properties if supported.
>>
>> We setup dma_pfn_offset using "dma-ranges" and dma_coherent_ops
>> using "dma-coherent" device tree properties.
>>
>> The set_arch_dma_coherent_ops macro has to be defined by arch if
>> it supports coherent dma_ops. Otherwise, set_arch_dma_coherent_ops() is
>> declared as nop.
>>
>
> [...]
>
>> + /*
>> + * if dma-ranges property doesn't exist - just return else
>> + * setup the dma offset
>> + */
>> + ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
>> + if ((ret == -ENODEV) || (ret < 0)) {
>
> The 1st condition is redundant.
>
>> + dev_dbg(dev, "no dma range information to setup\n");
>> + return;
>> + }
>> +
>> + /* DMA ranges found. Calculate and set dma_pfn_offset */
>> + dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
>> + dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset);
>> +}
>> +
>> +/**
>> * of_platform_device_create_pdata - Alloc, initialize and register an of_device
>> * @np: pointer to node to create device for
>> * @bus_id: name to assign device
>> @@ -214,9 +258,7 @@ static struct platform_device *of_platform_device_create_pdata(
>> #if defined(CONFIG_MICROBLAZE)
>> dev->archdata.dma_mask = 0xffffffffUL;
>> #endif
>
> This is also dma related setup. Please move *all* dma setup into the function.
>
Updated patch with above minor updates.

>From 80a9f06a09a90801d8ee337d9b2d155c43da8f23 Mon Sep 17 00:00:00 2001
From: Santosh Shilimkar <santosh.shilimkar@ti.com>
Date: Thu, 24 Apr 2014 11:30:04 -0400
Subject: [PATCH v3 4/7] of: configure the platform device dma parameters

Retrieve DMA configuration from DT and setup platform device's DMA
parameters. The DMA configuration in DT has to be specified using
"dma-ranges" and "dma-coherent" properties if supported.

We setup dma_pfn_offset using "dma-ranges" and dma_coherent_ops
using "dma-coherent" device tree properties.

The set_arch_dma_coherent_ops macro has to be defined by arch if
it supports coherent dma_ops. Otherwise, set_arch_dma_coherent_ops() is
declared as nop.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
drivers/of/platform.c | 55 ++++++++++++++++++++++++++++++++++++++-----
include/linux/dma-mapping.h | 7 ++++++
2 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 404d1da..b71e089 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -187,6 +187,54 @@ struct platform_device *of_device_alloc(struct device_node *np,
EXPORT_SYMBOL(of_device_alloc);

/**
+ * of_dma_configure - Setup DMA configuration
+ * @dev: Device to apply DMA configuration
+ *
+ * Try to get devices's DMA configuration from DT and update it
+ * accordingly.
+ *
+ * In case if platform code need to use own special DMA configuration,it
+ * can use Platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE event
+ * to fix up DMA configuration.
+ */
+static void of_dma_configure(struct platform_device *pdev)
+{
+ u64 dma_addr, paddr, size;
+ int ret;
+ struct device *dev = &pdev->dev;
+
+#if defined(CONFIG_MICROBLAZE)
+ pdev->archdata.dma_mask = 0xffffffffUL;
+#endif
+ dev->coherent_dma_mask = DMA_BIT_MASK(32);
+ if (!dev->dma_mask)
+ dev->dma_mask = &dev->coherent_dma_mask;
+
+ /*
+ * if dma-coherent property exist, call arch hook to setup
+ * dma coherent operations.
+ */
+ if (of_dma_is_coherent(dev->of_node)) {
+ set_arch_dma_coherent_ops(dev);
+ dev_dbg(dev, "device is dma coherent\n");
+ }
+
+ /*
+ * if dma-ranges property doesn't exist - just return else
+ * setup the dma offset
+ */
+ ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
+ if (ret < 0) {
+ dev_dbg(dev, "no dma range information to setup\n");
+ return;
+ }
+
+ /* DMA ranges found. Calculate and set dma_pfn_offset */
+ dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
+ dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset);
+}
+
+/**
* of_platform_device_create_pdata - Alloc, initialize and register an of_device
* @np: pointer to node to create device for
* @bus_id: name to assign device
@@ -211,12 +259,7 @@ static struct platform_device *of_platform_device_create_pdata(
if (!dev)
return NULL;

-#if defined(CONFIG_MICROBLAZE)
- dev->archdata.dma_mask = 0xffffffffUL;
-#endif
- dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
- if (!dev->dev.dma_mask)
- dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
+ of_dma_configure(dev);
dev->dev.bus = &platform_bus_type;
dev->dev.platform_data = platform_data;

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index fd4aee2..c7d9b1b 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -123,6 +123,13 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)

extern u64 dma_get_required_mask(struct device *dev);

+#ifndef set_arch_dma_coherent_ops
+static inline int set_arch_dma_coherent_ops(struct device *dev)
+{
+ return 0;
+}
+#endif
+
static inline unsigned int dma_get_max_seg_size(struct device *dev)
{
return dev->dma_parms ? dev->dma_parms->max_segment_size : 65536;
--
1.7.9.5