From b386559b2f94f15566a78af43b4c3446c79bc16a Mon Sep 17 00:00:00 2001 From: Lukasz Majewski Date: Wed, 5 Feb 2014 10:10:42 +0100 Subject: [PATCH] usb:udc:samsung: Remove redundant cache operation from Samsung UDC driver 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 Change-Id: Ie3222fb1a1170b47218442f5763a082aa2fac403 Signed-off-by: Lukasz Majewski Cc: Marek Vasut --- drivers/usb/gadget/s3c_udc_otg_xfer_dma.c | 17 ----------------- 1 file changed, 17 deletions(-) diff --git a/drivers/usb/gadget/s3c_udc_otg_xfer_dma.c b/drivers/usb/gadget/s3c_udc_otg_xfer_dma.c index 8f46284e7..d65ac89bf 100644 --- a/drivers/usb/gadget/s3c_udc_otg_xfer_dma.c +++ b/drivers/usb/gadget/s3c_udc_otg_xfer_dma.c @@ -42,10 +42,6 @@ static inline void s3c_udc_ep0_zlp(struct s3c_udc *dev) { u32 ep_ctrl; - flush_dcache_range((unsigned long) usb_ctrl_dma_addr, - (unsigned long) usb_ctrl_dma_addr - + DMA_BUFFER_SIZE); - writel(usb_ctrl_dma_addr, ®->in_endp[EP0_CON].diepdma); writel(DIEPT_SIZ_PKT_CNT(1), ®->in_endp[EP0_CON].dieptsiz); @@ -65,10 +61,6 @@ void s3c_udc_pre_setup(void) debug_cond(DEBUG_IN_EP, "%s : Prepare Setup packets.\n", __func__); - invalidate_dcache_range((unsigned long) usb_ctrl_dma_addr, - (unsigned long) usb_ctrl_dma_addr - + DMA_BUFFER_SIZE); - writel(DOEPT_SIZ_PKT_CNT(1) | sizeof(struct usb_ctrlrequest), ®->out_endp[EP0_CON].doeptsiz); writel(usb_ctrl_dma_addr, ®->out_endp[EP0_CON].doepdma); @@ -95,10 +87,6 @@ static inline void s3c_ep0_complete_out(void) debug_cond(DEBUG_IN_EP, "%s : Prepare Complete Out packet.\n", __func__); - invalidate_dcache_range((unsigned long) usb_ctrl_dma_addr, - (unsigned long) usb_ctrl_dma_addr - + DMA_BUFFER_SIZE); - writel(DOEPT_SIZ_PKT_CNT(1) | sizeof(struct usb_ctrlrequest), ®->out_endp[EP0_CON].doeptsiz); writel(usb_ctrl_dma_addr, ®->out_endp[EP0_CON].doepdma); @@ -128,11 +116,6 @@ static int setdma_rx(struct s3c_ep *ep, struct s3c_request *req) ep->len = length; ep->dma_buf = buf; - invalidate_dcache_range((unsigned long) ep->dev->dma_buf[ep_num], - (unsigned long) ep->dev->dma_buf[ep_num] - + ROUND(ep->ep.maxpacket, - CONFIG_SYS_CACHELINE_SIZE)); - if (length == 0) pktcnt = 1; else -- 2.34.1