On Friday 26 July 2013 11:10 AM, Russell King - ARM Linux wrote: > On Fri, Jul 12, 2013 at 05:48:09PM -0400, Santosh Shilimkar wrote: >> The series is an attempt to move ARM port to NO_BOOTMEM. As discussed >> on list NO_BOOTMEM move needed updates to max*pfn meaning to be maximum >> PFNs but that breaks the dma_mask for few block layer drivers since >> ARM start of physical memory is not PFN0 unlike most of the architectures. >> Some more read on it is here: >> http://lwn.net/Articles/543408/ >> http://lwn.net/Articles/543424/ >> >> To address this issue, we introduce generic dma_max_pfn() helper which >> can be overridden from the architectures. >> >> Another intention behind move to nobootmem is also to convert ARM to >> switch to memblock and getting rid of bootmem allocator dependency which >> don't work for LPAE machines which has physical memory starting beyond >> 4 GB boundary. It needs changes to core kernel and also a new memblock >> API. More on this can be found here: >> https://lkml.org/lkml/2013/6/29/77 >> >> I have been trying to cook up these patches with kind help from Russell >> and we know series don't solve all the dma_mask bad assumptions. But at >> least I am hoping that it can get the ball rolling. >> >> Comments/testing help is welcome !! > > As this is related to some of the cleanup of dma_mask which I've been > doing, I think it may make sense to roll this into one tree. Any > objection to that? > > Can we get any acks on this stuff from Jens and Jejb etc - especially > for the bits which touch block/ and for the scsi bits as these are > touching other subsystems. (oddly, linux-scsi wasn't on the original > mail for this series summary.) > Sorry I missed the scsi lists on the summary patch. While browsing the code I found another spot in mmc layer which needs fixing. The patch is at the end of the email with Chris and linux-mmc cc'ed here. Regards, Santosh >From 06a27a784a1fd86bf22adf1b247ac82a7c21d46b Mon Sep 17 00:00:00 2001 From: Santosh Shilimkar <santosh.shilimkar@xxxxxx> Date: Fri, 19 Jul 2013 21:36:46 -0400 Subject: [PATCH] mmc: Use dma_max_pfn(dev) helper for bounce_limit calculations DMA bounce limit is the maximum direct DMA'able memory beyond which bounce buffers has to be used to perform dma operations. MMC queue layer relies on dma_mask but its calculation is based on max_*pfn which don't have uniform meaning across architectures. So make use of dma_max_pfn() which is expected to return the DMAable maximum pfn value across architectures. Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Cc: Chris Ball <cjb@xxxxxxxxxx> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx> --- drivers/mmc/card/queue.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c index fa9632e..357bbc5 100644 --- a/drivers/mmc/card/queue.c +++ b/drivers/mmc/card/queue.c @@ -15,6 +15,7 @@ #include <linux/freezer.h> #include <linux/kthread.h> #include <linux/scatterlist.h> +#include <linux/dma-mapping.h> #include <linux/mmc/card.h> #include <linux/mmc/host.h> @@ -196,7 +197,7 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, struct mmc_queue_req *mqrq_prev = &mq->mqrq[1]; if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask) - limit = *mmc_dev(host)->dma_mask; + limit = dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT; mq->card = card; mq->queue = blk_init_queue(mmc_request_fn, lock); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
