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Message-ID: <CAL_Jsq+Y8w0sLLdh5vcWMnW3ohEafAFRWubtCK66P1axsf1wRA@mail.gmail.com>
Date: Thu, 6 Mar 2014 21:49:40 -0600
From: Rob Herring <robherring2@...il.com>
To: Santosh Shilimkar <santosh.shilimkar@...com>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
Grygorii Strashko <grygorii.strashko@...com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Russell King <linux@....linux.org.uk>,
Arnd Bergmann <arnd@...db.de>, Olof Johansson <olof@...om.net>,
Grant Likely <grant.likely@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH 4/7] of: configure the platform device dma_mask and dma_pfn_offset
On Thu, Mar 6, 2014 at 3:19 AM, Santosh Shilimkar
<santosh.shilimkar@...com> wrote:
> From: Grygorii Strashko <grygorii.strashko@...com>
>
> Retrieve DMA configuration from DT and setup platform device's DMA
> parameters.
>
> The DMA configuration in DT has to be specified using "dma-ranges"
> property if supported. The DMA configuration applied
> by dt_dma_configure() as following:
> - call of_get_dma_range() and get supported DMA range info
> (dma_addr, cpu_addr, dma_size);
> - if "not found" then fill dma_mask as DMA_BIT_MASK(32)
> (this is default behaviour);
> - if "failed" then clean up dma_mask (DMA not supported)
> - if ok then update devices DMA configuration:
> set dma_mask to (dma_addr + dma_size - 1)
> set dma_pfn_offset to PFN_DOWN(cpu_addr - dma_addr)
>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Russell King <linux@....linux.org.uk>
> Cc: Arnd Bergmann <arnd@...db.de>
> Cc: Olof Johansson <olof@...om.net>
> Cc: Grant Likely <grant.likely@...aro.org>
> Cc: Rob Herring <robh+dt@...nel.org>
> Cc: Catalin Marinas <catalin.marinas@....com>
> Cc: Linus Walleij <linus.walleij@...aro.org>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@...com>
> ---
> drivers/of/platform.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 72 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index bd080db..53bb12f 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -187,6 +187,77 @@ struct platform_device *of_device_alloc(struct device_node *np,
> EXPORT_SYMBOL(of_device_alloc);
>
> /**
> + * dt_dma_configure - apply default DMA configuration from dt
s/dt_/of_/
> + * @dev: Device to apply DMA configuration
> + *
> + * Try to get devices's DMA configuration from DT and apply it.
> + * The DMA configuration is represented in DT by "dma-ranges" property.
> + * It configures:
> + * dma_pfn_offset, dma_mask and coherent_dma_mask.
> + *
> + * In case if DMA configuration can't be acquired from DT the default one is
> + * applied:
> + * dma_pfn_offset = 0,
> + * dma_mask = DMA_BIT_MASK(32)
This is really set to &coherent_dma_mask.
> + * coherent_dma_mask = DMA_BIT_MASK(32).
> +
> + * In case if platform code need to use own DMA configuration - it can use
> + * Platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE event to fix up
> + * DMA configuration.
> + */
> +static void dt_dma_configure(struct device *dev)
s/dt_/of_/
> +{
> + dma_addr_t dma_addr;
> + phys_addr_t paddr, size;
> + dma_addr_t dma_mask;
> + int ret;
> +
> + /*
> + * if dma-ranges property doesn't exist - use 32 bits DMA mask
> + * by default and don't set skip archdata.dma_pfn_offset
> + */
> + ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
> + if (ret == -ENODEV) {
> + dev->coherent_dma_mask = DMA_BIT_MASK(32);
> + if (!dev->dma_mask)
> + dev->dma_mask = &dev->coherent_dma_mask;
> + return;
> + }
> +
> + /* if failed - disable DMA for device */
> + if (ret < 0) {
> + dev_err(dev, "failed to configure DMA\n");
> + return;
> + }
> +
> + /* DMA ranges found. Calculate and set dma_pfn_offset */
> + dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
> +
> + /* Configure DMA mask */
> + dev->dma_mask = &dev->coherent_dma_mask;
> + if (!dev->dma_mask)
This condition is impossible.
> + return;
> +
> + dma_mask = dma_addr + size - 1;
> +
> + ret = dma_set_mask(dev, dma_mask);
> + if (ret < 0) {
> + dev_err(dev, "failed to set DMA mask %pad\n", &dma_mask);
> + dev->dma_mask = NULL;
> + return;
> + }
> +
> + dev_dbg(dev, "dma_pfn_offset(%#08lx) dma_mask(%pad)\n",
> + dev->dma_pfn_offset, dev->dma_mask);
> +
> + ret = dma_set_coherent_mask(dev, dma_mask);
I think these 2 calls belong in the drivers, not here.
> + if (ret < 0) {
> + dev_err(dev, "failed to set coherent DMA mask %pad\n",
> + &dma_mask);
> + }
> +}
> +
> +/**
> * 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 +285,7 @@ static struct platform_device *of_platform_device_create_pdata(
> #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;
> + dt_dma_configure(&dev->dev);
> dev->dev.bus = &platform_bus_type;
> dev->dev.platform_data = platform_data;
>
> --
> 1.7.9.5
>
--
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