Hi Mika, >-----Original Message----- >From: Mika Westerberg [mailto:mika.westerberg@xxxxxxxxxxxxxxx] >Sent: Monday, January 04, 2016 10:46 PM >To: Wang, Annie >Cc: Andy Shevchenko; Vinod Koul; Greg Kroah-Hartman; Rafael J. Wysocki; linux- >acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-serial@xxxxxxxxxxxxxxx; >dmaengine@xxxxxxxxxxxxxxx; Borislav Petkov; Huang, Ray; Wan, Vincent; Xue, >Ken; Robin Murphy; Graeme Gregory; Li, Tony; Yu, Xiangliang >Subject: Re: [PATCH 3/6] ACPI: add 2 parameters to function acpi dma controller >register > >On Mon, Jan 04, 2016 at 01:31:38PM +0800, Wang Hongcheng wrote: >> As CSRT table will not always work, 2 arguments, base_request_line and >> num are added to acpi dma controller register as another way to get >> device request line. >> >> Signed-off-by: Wang Hongcheng <annie.wang@xxxxxxx> >> --- >> drivers/dma/acpi-dma.c | 25 ++++++++++++++++++++----- >> drivers/dma/dw/platform.c | 2 +- >> include/linux/acpi_dma.h | 6 ++++++ >> 3 files changed, 27 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c index >> 16d0daa..e2c27c3 100644 >> --- a/drivers/dma/acpi-dma.c >> +++ b/drivers/dma/acpi-dma.c >> @@ -105,7 +105,7 @@ static int acpi_dma_parse_resource_group(const struct >acpi_csrt_group *grp, >> * We are using this table to get the request line range of the specific DMA >> * controller to be used later. >> */ >> -static void acpi_dma_parse_csrt(struct acpi_device *adev, struct >> acpi_dma *adma) >> +static int acpi_dma_parse_csrt(struct acpi_device *adev, struct >> +acpi_dma *adma) >> { >> struct acpi_csrt_group *grp, *end; >> struct acpi_table_csrt *csrt; >> @@ -117,7 +117,7 @@ static void acpi_dma_parse_csrt(struct acpi_device >*adev, struct acpi_dma *adma) >> if (ACPI_FAILURE(status)) { >> if (status != AE_NOT_FOUND) >> dev_warn(&adev->dev, "failed to get the CSRT table\n"); >> - return; >> + return -ENOENT; >> } >> >> grp = (struct acpi_csrt_group *)(csrt + 1); @@ -128,11 +128,12 @@ >> static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma >*adma) >> if (ret < 0) { >> dev_warn(&adev->dev, >> "error in parsing resource group\n"); >> - return; >> + return -EINVAL; >> } >> >> grp = (struct acpi_csrt_group *)((void *)grp + grp->length); >> } >> + return 0; >> } >> >> /** >> @@ -140,6 +141,8 @@ static void acpi_dma_parse_csrt(struct acpi_device >*adev, struct acpi_dma *adma) >> * @dev: struct device of DMA controller >> * @acpi_dma_xlate: translation function which converts a dma specifier >> * into a dma_chan structure >> + * @base_request_line: device request line base >> + * @num: device request line range >> * @data pointer to controller specific data to be used by >> * translation function >> * >> @@ -152,10 +155,13 @@ static void acpi_dma_parse_csrt(struct >> acpi_device *adev, struct acpi_dma *adma) int >acpi_dma_controller_register(struct device *dev, >> struct dma_chan *(*acpi_dma_xlate) >> (struct acpi_dma_spec *, struct acpi_dma *), >> + unsigned short base_request_line, >> + unsigned short num, >> void *data) > >Can you instead provide custom acpi_dma_xlate when you register the DMA >controller? That function can then use whatever translation scheme is suitable for >your platform to get the correct channel. Acpi_dma_xlate mainly converts an acpi_dma structure into a dma_chan structure. Without proper request line, wrong acpi_dma structure may be get. And as Andy says in http://article.gmane.org/gmane.linux.kernel.iommu/11675 How about add a hook into acpi_dma_controller_register? Regards, Hongcheng (Annie) -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
