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https://github.com/brain-hackers/u-boot-brain
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716662bd19
A set of cache operations (both invalidation and flush) were redundant in the S3C HS OTG Samsung driver: 1. s3c_udc_ep0_zlp - to transmit EP0's ZLP packets one don't need to flush the cache (since it is the zero length transmission) 2. s3c_udc_pre_setup and s3c_ep0_complete_out - cache invalidation is not needed when the buffer for OUT EP0 transmission is setup, since no data has yet arrived. Cache cleanups presented above don't contribute much to transmission speed up, hence shall be regarded as cosmetic changes. 3. setdma_rx - here the s3c UDC driver's internal buffers were invalidated. This call is not needed anymore since we reuse the buffers passed from gadgets. This is a key contribution to transmission speed improvement. Test condition - test HW + measurement: Trats - Exynos4210 rev.1 - test HW Trats2 - Exynos4412 rev.1 400 MiB compressed rootfs image download with `thor 0 mmc 0` Measurements: Base values (without improvement): Transmission speed: 9.51 MiB/s After the change: Transmission speed: 10.15 MiB/s Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> Cc: Marek Vasut <marex@denx.de> |
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