Revision 9a765881bf3dcd32847d7108cf48cb04a4ed993f authored by Bjørn Mork on 10 October 2016, 19:12:49 UTC, committed by David S. Miller on 13 October 2016, 14:05:06 UTC
The Quectel EC21 and EC25 need the same "set DTR" request as devices
based on the MDM9230 chipset, but has no USB3 support. Our best guess
is that the "set DTR" functionality depends on chipset and/or
baseband firmware generation. But USB3 is still an optional feature.

Since we cannot enable this unconditionally for all older devices, and
there doesn't appear to be anything we can use in the USB descriptors
to identify these chips, we are forced to use a device specific quirk
flag.

Reported-and-tested-by: Sebastian Sjoholm <sebastian.sjoholm@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 4013bee
Raw File
dma-noop.c
/*
 *	lib/dma-noop.c
 *
 * Simple DMA noop-ops that map 1:1 with memory
 */
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>

static void *dma_noop_alloc(struct device *dev, size_t size,
			    dma_addr_t *dma_handle, gfp_t gfp,
			    unsigned long attrs)
{
	void *ret;

	ret = (void *)__get_free_pages(gfp, get_order(size));
	if (ret)
		*dma_handle = virt_to_phys(ret);
	return ret;
}

static void dma_noop_free(struct device *dev, size_t size,
			  void *cpu_addr, dma_addr_t dma_addr,
			  unsigned long attrs)
{
	free_pages((unsigned long)cpu_addr, get_order(size));
}

static dma_addr_t dma_noop_map_page(struct device *dev, struct page *page,
				      unsigned long offset, size_t size,
				      enum dma_data_direction dir,
				      unsigned long attrs)
{
	return page_to_phys(page) + offset;
}

static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
			     enum dma_data_direction dir,
			     unsigned long attrs)
{
	int i;
	struct scatterlist *sg;

	for_each_sg(sgl, sg, nents, i) {
		void *va;

		BUG_ON(!sg_page(sg));
		va = sg_virt(sg);
		sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va);
		sg_dma_len(sg) = sg->length;
	}

	return nents;
}

static int dma_noop_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
	return 0;
}

static int dma_noop_supported(struct device *dev, u64 mask)
{
	return 1;
}

struct dma_map_ops dma_noop_ops = {
	.alloc			= dma_noop_alloc,
	.free			= dma_noop_free,
	.map_page		= dma_noop_map_page,
	.map_sg			= dma_noop_map_sg,
	.mapping_error		= dma_noop_mapping_error,
	.dma_supported		= dma_noop_supported,
};

EXPORT_SYMBOL(dma_noop_ops);
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