| Message ID | 536806F4.1090904@ti.com |
|---|---|
| State | New |
| Headers | show |
On Mon, May 5, 2014 at 4:47 PM, Santosh Shilimkar <santosh.shilimkar@ti.com> wrote: > 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: > 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> Reviewed-by: Rob Herring <robh@kernel.org> > --- > 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 > > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Monday 05 May 2014 17:47:32 Santosh Shilimkar wrote: > + dev->coherent_dma_mask = DMA_BIT_MASK(32); > + if (!dev->dma_mask) > + dev->dma_mask = &dev->coherent_dma_mask; > + > + /* > + * 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); > +} I think there should at least be a comment about why we are computing the correct DMA mask here and then ignore that and just use DMA_BIT_MASK(32) instead. I understand that Russell and Rob prefer it that way and I'm not going to argue, but I find it counterintuitive and I think it deserves an explanation in the source code for anybody who is trying to figure out how things fit together. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On Tuesday 06 May 2014 05:40 AM, Arnd Bergmann wrote: > On Monday 05 May 2014 17:47:32 Santosh Shilimkar wrote: > >> + dev->coherent_dma_mask = DMA_BIT_MASK(32); >> + if (!dev->dma_mask) >> + dev->dma_mask = &dev->coherent_dma_mask; >> + >> + /* >> + * 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); >> +} > > I think there should at least be a comment about why we are computing > the correct DMA mask here and then ignore that and just use DMA_BIT_MASK(32) > instead. I understand that Russell and Rob prefer it that way and I'm not > going to argue, but I find it counterintuitive and I think it deserves > an explanation in the source code for anybody who is trying to figure > out how things fit together. > In this patch, the dma_mask related code is just moved. We are not calculating dma_mask either. I was looking for the history of how DMA_BIT_MASK(32) landed up but couldn't trace it down apart from the fact that the code was carried from powerPC. May be Rob knows. How about below comment ? I didn't delibratly added point about bus intercepting drivers dma_set_*mask() call etc. /* * Set default dma-mask to 32 bit. Drivers are expected to setup * the correct supported dma_mask. */ + dev->coherent_dma_mask = DMA_BIT_MASK(32); + if (!dev->dma_mask) + dev->dma_mask = &dev->coherent_dma_mask; Regards, Santosh -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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;