MUSB RTL version 1.4 has a hardware issue when TX and RX DMA channels are simultaneously enabled which results in DMA lockup.
Use system DMA for all RX channels as a workaround of this issue as this will have minimal throughput overhead based on the fact that Rx transfers are done in DMA mode-0 on OMAP34x/35x platforms. Another approach to use PIO mode in opposite direction would increase the cpu loading and thus using system DMA is preferred workaround. Signed-off-by: Anand Gadiyar <gadi...@ti.com> Signed-off-by: Ajay Kumar Gupta <ajay.gu...@ti.com> --- Original version of this patch can be found at, http://marc.info/?l=linux-usb&m=121861118320955&w=2 drivers/usb/musb/Kconfig | 9 ++++ drivers/usb/musb/musbhsdma.c | 101 ++++++++++++++++++++++++++++++++++++++++++ drivers/usb/musb/musbhsdma.h | 10 ++++ 3 files changed, 120 insertions(+), 0 deletions(-) diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig index 07fe490..f847fe2 100644 --- a/drivers/usb/musb/Kconfig +++ b/drivers/usb/musb/Kconfig @@ -157,6 +157,15 @@ config USB_INVENTRA_DMA help Enable DMA transfers using Mentor's engine. +config MUSB_USE_SYSTEM_DMA_WORKAROUND + bool 'Use System DMA for Mentor DMA workaround' + depends on USB_MUSB_HDRC && USB_INVENTRA_DMA + default y + help + MUSB RTL version 1.4 (OMAP34x/35x) has a hardware issue when TX and RX + DMA channels are simultaneously enabled. To work around this issue, + you can choose to use System DMA for RX channels. + config USB_TI_CPPI_DMA bool depends on USB_MUSB_HDRC && !MUSB_PIO_ONLY diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c index 1008044..70342eb 100644 --- a/drivers/usb/musb/musbhsdma.c +++ b/drivers/usb/musb/musbhsdma.c @@ -36,12 +36,47 @@ #include <linux/slab.h> #include "musb_core.h" #include "musbhsdma.h" +#include <plat/dma.h> static int dma_controller_start(struct dma_controller *c) { /* nothing to do */ return 0; } +static void musb_sysdma_completion(int lch, u16 ch_status, void *data) +{ + u32 addr; + unsigned long flags; + + struct dma_channel *channel; + + struct musb_dma_channel *musb_channel = + (struct musb_dma_channel *) data; + struct musb_dma_controller *controller = musb_channel->controller; + struct musb *musb = controller->private_data; + channel = &musb_channel->channel; + + DBG(2, "lch = 0x%d, ch_status = 0x%x\n", lch, ch_status); + spin_lock_irqsave(&musb->lock, flags); + + addr = (u32) omap_get_dma_dst_pos(musb_channel->sysdma_channel); + if (musb_channel->len == 0) + channel->actual_len = 0; + else + channel->actual_len = addr - musb_channel->start_addr; + + DBG(2, "ch %p, 0x%x -> 0x%x (%d / %d) %s\n", + channel, musb_channel->start_addr, addr, + channel->actual_len, musb_channel->len, + (channel->actual_len < musb_channel->len) ? + "=> reconfig 0 " : " => complete"); + + channel->status = MUSB_DMA_STATUS_FREE; + musb_dma_completion(musb, musb_channel->epnum, musb_channel->transmit); + + spin_unlock_irqrestore(&musb->lock, flags); + return; +} static void dma_channel_release(struct dma_channel *channel); @@ -77,6 +112,7 @@ static struct dma_channel *dma_channel_allocate(struct dma_controller *c, struct musb_dma_controller *controller = container_of(c, struct musb_dma_controller, controller); struct musb_dma_channel *musb_channel = NULL; + struct musb *musb = controller->private_data; struct dma_channel *channel = NULL; u8 bit; @@ -95,6 +131,33 @@ static struct dma_channel *dma_channel_allocate(struct dma_controller *c, /* Tx => mode 1; Rx => mode 0 */ channel->desired_mode = transmit; channel->actual_len = 0; + musb_channel->sysdma_channel = -1; + + /* + * MUSB RTL version 1.4 (OMAP34x/35x) has a hardware + * issue when TX and RX DMA channels are simultaneously + * enabled. To work around this issue, use system DMA + * for all RX channels. + */ + if (((musb->hwvers == MUSB_HWVERS_1400) && !transmit) + && use_sdma_workaround()) { + int ret; + ret = omap_request_dma(OMAP24XX_DMA_NO_DEVICE, + "MUSB SysDMA", musb_sysdma_completion, + (void *) musb_channel, + &(musb_channel->sysdma_channel)); + + if (ret) { + printk(KERN_ERR "request_dma failed:" + " %d\n", ret); + controller->used_channels &= + ~(1 << bit); + channel->status = + MUSB_DMA_STATUS_UNKNOWN; + musb_channel->sysdma_channel = -1; + channel = NULL; + } + } break; } } @@ -114,6 +177,12 @@ static void dma_channel_release(struct dma_channel *channel) ~(1 << musb_channel->idx); channel->status = MUSB_DMA_STATUS_UNKNOWN; + + if (musb_channel->sysdma_channel != -1) { + omap_stop_dma(musb_channel->sysdma_channel); + omap_free_dma(musb_channel->sysdma_channel); + musb_channel->sysdma_channel = -1; + } } static void configure_channel(struct dma_channel *channel, @@ -122,12 +191,40 @@ static void configure_channel(struct dma_channel *channel, { struct musb_dma_channel *musb_channel = channel->private_data; struct musb_dma_controller *controller = musb_channel->controller; + struct musb *musb = controller->private_data; void __iomem *mbase = controller->base; u8 bchannel = musb_channel->idx; u16 csr = 0; DBG(4, "%p, pkt_sz %d, addr 0x%x, len %d, mode %d\n", channel, packet_sz, dma_addr, len, mode); + if (musb_channel->sysdma_channel != -1) { + /* System DMA */ + /* RX: set src = FIFO */ + omap_set_dma_transfer_params(musb_channel->sysdma_channel, + OMAP_DMA_DATA_TYPE_S8, + len ? len : 1, 1, /* One frame */ + OMAP_DMA_SYNC_ELEMENT, + OMAP24XX_DMA_NO_DEVICE, + 0); /* Src Sync */ + + omap_set_dma_src_params(musb_channel->sysdma_channel, 0, + OMAP_DMA_AMODE_CONSTANT, + MUSB_FIFO_ADDRESS(musb->ctrl_phys_base, + musb_channel->epnum), + 0, 0); + + omap_set_dma_dest_params(musb_channel->sysdma_channel, 0, + OMAP_DMA_AMODE_POST_INC, dma_addr, + 0, 0); + + omap_set_dma_dest_data_pack(musb_channel->sysdma_channel, 1); + omap_set_dma_dest_burst_mode(musb_channel->sysdma_channel, + OMAP_DMA_DATA_BURST_16); + + omap_start_dma(musb_channel->sysdma_channel); + + } else { /* Mentor DMA */ if (mode) { csr |= 1 << MUSB_HSDMA_MODE1_SHIFT; @@ -160,6 +257,7 @@ static void configure_channel(struct dma_channel *channel, musb_writew(mbase, MUSB_HSDMA_CHANNEL_OFFSET(bchannel, MUSB_HSDMA_CONTROL), csr); + } } static int dma_channel_program(struct dma_channel *channel, @@ -214,6 +312,9 @@ static int dma_channel_abort(struct dma_channel *channel) csr &= ~MUSB_TXCSR_DMAMODE; musb_writew(mbase, offset, csr); } else { + if (musb_channel->sysdma_channel != -1) + omap_stop_dma(musb_channel->sysdma_channel); + offset = MUSB_EP_OFFSET(musb_channel->epnum, MUSB_RXCSR); diff --git a/drivers/usb/musb/musbhsdma.h b/drivers/usb/musb/musbhsdma.h index 613f95a..effc89a 100644 --- a/drivers/usb/musb/musbhsdma.h +++ b/drivers/usb/musb/musbhsdma.h @@ -142,6 +142,15 @@ static inline void musb_write_hsdma_count(void __iomem *mbase, #define MUSB_HSDMA_CHANNELS 8 +#define MUSB_FIFO_ADDRESS(base, epnum) \ + ((unsigned long) (base + MUSB_FIFO_OFFSET(epnum))) + +#ifdef CONFIG_MUSB_USE_SYSTEM_DMA_WORKAROUND +#define use_sdma_workaround() 1 +#else +#define use_sdma_workaround() 0 +#endif + struct musb_dma_controller; struct musb_dma_channel { @@ -153,6 +162,7 @@ struct musb_dma_channel { u8 idx; u8 epnum; u8 transmit; + int sysdma_channel; }; struct musb_dma_controller { -- 1.6.2.4 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
