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On some platforms like DM355, the number of EDMA parameter slots available for EDMA_SLOT_ANY usage are few. In such cases, if MMC/SD uses 16 slots for each instance of MMC controller, then the number of slots available for other modules will be very few. By passing the number of EDMA slots to be used in MMC driver from platform data, EDMA slots available for other purposes can be controlled. Most of the platforms will not use this platform data variable. But on DM355, as the number of EDMA resources available is limited, the number of scatter- gather segments used inside the MMC driver can be 8 (passed as platform data) instead of 16. On DM355, when the number of scatter-gather segments was reduced to 8, I saw a performance difference of about 0.25-0.4 Mbytes/sec during write. Read performance variations were negligible. Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com> Acked-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
37 lines
708 B
C
37 lines
708 B
C
/*
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* Board-specific MMC configuration
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*/
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#ifndef _DAVINCI_MMC_H
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#define _DAVINCI_MMC_H
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#include <linux/types.h>
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#include <linux/mmc/host.h>
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struct davinci_mmc_config {
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/* get_cd()/get_wp() may sleep */
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int (*get_cd)(int module);
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int (*get_ro)(int module);
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/* wires == 0 is equivalent to wires == 4 (4-bit parallel) */
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u8 wires;
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u32 max_freq;
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/* any additional host capabilities: OR'd in to mmc->f_caps */
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u32 caps;
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/* Version of the MMC/SD controller */
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u8 version;
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/* Number of sg segments */
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u8 nr_sg;
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};
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void davinci_setup_mmc(int module, struct davinci_mmc_config *config);
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enum {
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MMC_CTLR_VERSION_1 = 0, /* DM644x and DM355 */
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MMC_CTLR_VERSION_2, /* DA830 */
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};
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#endif
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