Messages in this thread | | | Date | Tue, 22 Apr 2014 17:56:31 +0300 | From | Grygorii Strashko <> | Subject | Re: [PATCH v2 2/7] of: introduce of_dma_get_range() helper |
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Hi Rob,
On 04/21/2014 06:29 PM, Rob Herring wrote: > On Sat, Apr 19, 2014 at 9:32 AM, Santosh Shilimkar > <santosh.shilimkar@ti.com> wrote: >> From: Grygorii Strashko <grygorii.strashko@ti.com> >> >> 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 <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 | 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.
Seems, It's not needed, because of_get_next_parent() does following: parent = of_node_get(node->parent); of_node_put(node);
> >> + } >> + >> + 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.
I think, We need to keep using of_translate_dma_address(), because this code intended to be generic and, as result, there is no guarantee that we will always have one level of translations.
> >> + if (*paddr == OF_BAD_ADDR) { > > As I mentioned, this is potentially a size mismatch.
Thanks for your review.
Regards, Grygorii
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