Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751925AbaDUP3T (ORCPT ); Mon, 21 Apr 2014 11:29:19 -0400 Received: from mail-ve0-f176.google.com ([209.85.128.176]:34385 "EHLO mail-ve0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751521AbaDUP3M (ORCPT ); Mon, 21 Apr 2014 11:29:12 -0400 MIME-Version: 1.0 In-Reply-To: <1397917972-6293-3-git-send-email-santosh.shilimkar@ti.com> References: <1397917972-6293-1-git-send-email-santosh.shilimkar@ti.com> <1397917972-6293-3-git-send-email-santosh.shilimkar@ti.com> Date: Mon, 21 Apr 2014 10:29:11 -0500 Message-ID: Subject: Re: [PATCH v2 2/7] of: introduce of_dma_get_range() helper From: Rob Herring To: Santosh Shilimkar Cc: "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , Grygorii Strashko , Greg Kroah-Hartman , Russell King , Arnd Bergmann , Olof Johansson , Grant Likely , Rob Herring , Catalin Marinas , Linus Walleij Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 19, 2014 at 9:32 AM, Santosh Shilimkar wrote: > From: Grygorii Strashko > > The of_dma_get_range() allows to find "dma-range" property for > the specified device and parse it. > dma-ranges format: > DMA addr (dma_addr) : naddr cells > CPU addr (phys_addr_t) : pna cells > size : nsize cells > > Cc: Greg Kroah-Hartman > Cc: Russell King > Cc: Arnd Bergmann > Cc: Olof Johansson > Cc: Grant Likely > Cc: Rob Herring > Cc: Catalin Marinas > Cc: Linus Walleij > Signed-off-by: Grygorii Strashko > Signed-off-by: Santosh Shilimkar > --- > drivers/of/platform.c | 85 +++++++++++++++++++++++++++++++++++++++++++ > include/linux/of_platform.h | 8 ++++ This belongs in drivers/of/address.c and of_address.h. > 2 files changed, 93 insertions(+) > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 404d1da..2265a55 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -485,4 +485,89 @@ int of_platform_populate(struct device_node *root, > return rc; > } > EXPORT_SYMBOL_GPL(of_platform_populate); > + > +/** > + * of_dma_get_range - Get DMA range info > + * @np: device node to get DMA range info > + * @dma_addr: pointer to store initial DMA address of DMA range > + * @paddr: pointer to store initial CPU address of DMA range > + * @size: pointer to store size of DMA range > + * > + * Look in bottom up direction for the first "dma-range" property dma-ranges > + * and parse it. > + * dma-ranges format: > + * DMA addr (dma_addr) : naddr cells > + * CPU addr (phys_addr_t) : pna cells > + * size : nsize cells > + * > + * It returns -ENODEV if "dma-ranges" property was not found > + * for this device in DT. > + */ > +extern int of_dma_get_range(struct device_node *np, dma_addr_t *dma_addr, drop extern. > + phys_addr_t *paddr, phys_addr_t *size) > +{ > + struct device_node *node = np; > + const u32 *ranges = NULL; __be32 > + int len, naddr, nsize, pna; > + int ret = 0; > + > + if (!node) > + return -EINVAL; > + > + while (1) { > + naddr = of_n_addr_cells(node); > + nsize = of_n_size_cells(node); > + node = of_get_next_parent(node); > + if (!node) > + break; > + > + ranges = of_get_property(node, "dma-ranges", &len); > + > + /* Ignore empty ranges, they imply no translation required */ > + if (ranges && len > 0) > + break; > + > + /* > + * At least empty ranges has to be defined for parent node if > + * DMA is supported > + */ > + if (!ranges) > + break; You need an of_node_put here if you are getting the next parent. > + } > + > + if (!ranges) { > + pr_debug("%s: no dma-ranges found for node(%s)\n", > + __func__, np->full_name); > + ret = -ENODEV; > + goto out; > + } > + > + len /= sizeof(u32); > + > + pna = of_n_addr_cells(node); > + > + /* dma-ranges format: > + * DMA addr : naddr cells > + * CPU addr : pna cells > + * size : nsize cells > + */ > + *dma_addr = of_read_number(ranges, naddr); You should set this after the following call succeeds. > + *paddr = of_translate_dma_address(np, ranges); This is going to search for dma-ranges again, but you have already done that. Is there a case that just reading the CPU addr will not work? I suppose we could have more than one level of translation. It also seems a bit abusive that the DMA address is the ranges property. I don't really have a better suggestion though. > + if (*paddr == OF_BAD_ADDR) { As I mentioned, this is potentially a size mismatch. Rob -- 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/