MUSB: Workaround for simultaneous TX and RX usage MUSB RTL V1.4 has a hardware issue which results in a DMA controller hang when TX and RX DMA channels are simultaneously enabled. This affects at least OMAP2430 and OMAP34XX. Since RX transfers are in Mode 0 and anyway result in one DMA interrupt per packet, we can use System DMA to unload the RX fifos. MUSB DMA can be used for all TX channels as before. Tested with full-duplex TX and RX transfers using g_ether. Runs for 24 hours without a hang. Without this patch, the hang occurs within minutes. This issue was first reported by Jon Hunter on [1] [1] http://marc.info/?l=linux-omap&m=119634480534453&w=2 Signed-off-by: Anand Gadiyar <gadiyar@xxxxxx> --- Patch based on the linux-omap tree. I believe the tabs-to-spaces issue has been resolved now, but this is the first patch I'm sending out to the list after that. Suggestions welcome for removing the 2 #ifdefs below. One suggestion was to use a module parameter to decide whether to use system dma or mentor dma. Patch updated with a few ifdefs removed and one compilation break resolved. drivers/usb/musb/Kconfig | 8 ++ drivers/usb/musb/musbhsdma.c | 163 +++++++++++++++++++++++++++++++++++-------- 2 files changed, 142 insertions(+), 29 deletions(-) Index: linux-omap-2.6/drivers/usb/musb/musbhsdma.c =================================================================== --- linux-omap-2.6.orig/drivers/usb/musb/musbhsdma.c 2008-07-28 10:54:37.000000000 +0530 +++ linux-omap-2.6/drivers/usb/musb/musbhsdma.c 2008-08-13 11:58:26.272902373 +0530 @@ -34,6 +34,7 @@ #include <linux/interrupt.h> #include <linux/platform_device.h> #include "musb_core.h" +#include <asm/arch/dma.h> #if defined(CONFIG_ARCH_OMAP2430) || defined(CONFIG_ARCH_OMAP3430) #include "omap2430.h" @@ -64,6 +65,9 @@ #define MUSB_HSDMA_CHANNELS 8 +#define MUSB_FIFO_ADDRESS(epnum) \ + ((unsigned long) (OMAP_HSOTG_BASE + MUSB_FIFO_OFFSET(epnum))) + struct musb_dma_controller; struct musb_dma_channel { @@ -75,6 +79,8 @@ struct musb_dma_channel { u8 bIndex; u8 epnum; u8 transmit; + + int sysdma_channel; }; struct musb_dma_controller { @@ -93,6 +99,42 @@ static int dma_controller_start(struct d return 0; } +#ifdef CONFIG_MUSB_USE_SYSTEM_DMA_RX +static void musb_sysdma_completion(int lch, u16 ch_status, void *data) +{ + u32 dwAddress; + unsigned long flags; + + struct dma_channel *pChannel; + + struct musb_dma_channel *pImplChannel = + (struct musb_dma_channel *) data; + struct musb_dma_controller *controller = pImplChannel->controller; + struct musb *musb = controller->pDmaPrivate; + pChannel = &pImplChannel->Channel; + + DBG(2, "lch = 0x%d, ch_status = 0x%x\n", lch, ch_status); + spin_lock_irqsave(&musb->lock, flags); + + dwAddress = (u32) omap_get_dma_dst_pos(pImplChannel->sysdma_channel); + pChannel->actual_len = dwAddress - pImplChannel->dwStartAddress; + + DBG(2, "ch %p, 0x%x -> 0x%x (%d / %d) %s\n", + pChannel, pImplChannel->dwStartAddress, dwAddress, + pChannel->actual_len, pImplChannel->len, + (pChannel->actual_len < pImplChannel->len) ? + "=> reconfig 0": "=> complete"); + + pChannel->status = MUSB_DMA_STATUS_FREE; + musb_dma_completion(musb, pImplChannel->epnum, pImplChannel->transmit); + + spin_unlock_irqrestore(&musb->lock, flags); + return; +} +#else +#define musb_sysdma_completion NULL +#endif + static void dma_channel_release(struct dma_channel *pChannel); static int dma_controller_stop(struct dma_controller *c) @@ -144,6 +186,29 @@ static struct dma_channel *dma_channel_a /* Tx => mode 1; Rx => mode 0 */ pChannel->desired_mode = transmit; pChannel->actual_len = 0; + pImplChannel->sysdma_channel = -1; + +#ifdef CONFIG_MUSB_USE_SYSTEM_DMA_RX + if (!transmit) { + int ret; + ret = omap_request_dma(OMAP24XX_DMA_NO_DEVICE, + "MUSB SysDMA", musb_sysdma_completion, + (void *) pImplChannel, + &(pImplChannel->sysdma_channel)); + + if (ret) { + printk(KERN_ERR "request_dma failed:" + " %d\n", ret); + controller->bmUsedChannels &= + ~(1 << bBit); + pChannel->status = + MUSB_DMA_STATUS_UNKNOWN; + pImplChannel->sysdma_channel = -1; + pChannel = NULL; + } + } +#endif + break; } } @@ -163,6 +228,12 @@ static void dma_channel_release(struct d ~(1 << pImplChannel->bIndex); pChannel->status = MUSB_DMA_STATUS_UNKNOWN; + + if (pImplChannel->sysdma_channel != -1) { + omap_stop_dma(pImplChannel->sysdma_channel); + omap_free_dma(pImplChannel->sysdma_channel); + pImplChannel->sysdma_channel = -1; + } } static void configure_channel(struct dma_channel *pChannel, @@ -179,41 +250,69 @@ static void configure_channel(struct dma DBG(4, "%p, pkt_sz %d, addr 0x%x, len %d, mode %d\n", pChannel, packet_sz, dma_addr, len, mode); - if (mode) { - csr |= 1 << MUSB_HSDMA_MODE1_SHIFT; - BUG_ON(len < packet_sz); + if (pImplChannel->sysdma_channel != -1) { + /* System DMA */ + /* RX: set src = FIFO */ + + omap_set_dma_transfer_params(pImplChannel->sysdma_channel, + OMAP_DMA_DATA_TYPE_S8, + len, 1, /* One frame */ + OMAP_DMA_SYNC_ELEMENT, + OMAP24XX_DMA_NO_DEVICE, + 0); /* Src Sync */ + + omap_set_dma_src_params(pImplChannel->sysdma_channel, 0, + OMAP_DMA_AMODE_CONSTANT, + MUSB_FIFO_ADDRESS(pImplChannel->epnum), + 0, 0); + + omap_set_dma_dest_params(pImplChannel->sysdma_channel, 0, + OMAP_DMA_AMODE_POST_INC, dma_addr, + 0, 0); + + omap_set_dma_dest_data_pack(pImplChannel->sysdma_channel, 1); + omap_set_dma_dest_burst_mode(pImplChannel->sysdma_channel, + OMAP_DMA_DATA_BURST_16); + + omap_start_dma(pImplChannel->sysdma_channel); + + } else { /* Mentor DMA */ + if (mode) { + csr |= 1 << MUSB_HSDMA_MODE1_SHIFT; + BUG_ON(len < packet_sz); - if (packet_sz >= 64) { - csr |= MUSB_HSDMA_BURSTMODE_INCR16 + if (packet_sz >= 64) { + csr |= MUSB_HSDMA_BURSTMODE_INCR16 << MUSB_HSDMA_BURSTMODE_SHIFT; - } else if (packet_sz >= 32) { - csr |= MUSB_HSDMA_BURSTMODE_INCR8 + } else if (packet_sz >= 32) { + csr |= MUSB_HSDMA_BURSTMODE_INCR8 << MUSB_HSDMA_BURSTMODE_SHIFT; - } else if (packet_sz >= 16) { - csr |= MUSB_HSDMA_BURSTMODE_INCR4 + } else if (packet_sz >= 16) { + csr |= MUSB_HSDMA_BURSTMODE_INCR4 << MUSB_HSDMA_BURSTMODE_SHIFT; + } } - } - csr |= (pImplChannel->epnum << MUSB_HSDMA_ENDPOINT_SHIFT) - | (1 << MUSB_HSDMA_ENABLE_SHIFT) - | (1 << MUSB_HSDMA_IRQENABLE_SHIFT) - | (pImplChannel->transmit - ? (1 << MUSB_HSDMA_TRANSMIT_SHIFT) - : 0); - - /* address/count */ - musb_writel(mbase, - MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_ADDRESS), - dma_addr); - musb_writel(mbase, - MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_COUNT), - len); - - /* control (this should start things) */ - musb_writew(mbase, - MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_CONTROL), - csr); + csr |= (pImplChannel->epnum << MUSB_HSDMA_ENDPOINT_SHIFT) + | (1 << MUSB_HSDMA_ENABLE_SHIFT) + | (1 << MUSB_HSDMA_IRQENABLE_SHIFT) + | (pImplChannel->transmit + ? (1 << MUSB_HSDMA_TRANSMIT_SHIFT) + : 0); + + /* address/count */ + musb_writel(mbase, + MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_ADDRESS), + dma_addr); + musb_writel(mbase, + MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_COUNT), + len); + + /* control (this should start things) */ + musb_writew(mbase, + MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_CONTROL), + csr); + } /* Mentor DMA */ } static int dma_channel_program(struct dma_channel *pChannel, @@ -265,6 +364,12 @@ static int dma_channel_abort(struct dma_ MUSB_EP_OFFSET(pImplChannel->epnum, MUSB_TXCSR), csr); } else { + if (pImplChannel->sysdma_channel != -1) { + omap_stop_dma(pImplChannel->sysdma_channel); + omap_free_dma(pImplChannel->sysdma_channel); + pImplChannel->sysdma_channel = -1; + } + csr = musb_readw(mbase, MUSB_EP_OFFSET(pImplChannel->epnum, MUSB_RXCSR)); csr &= ~(MUSB_RXCSR_AUTOCLEAR | Index: linux-omap-2.6/drivers/usb/musb/Kconfig =================================================================== --- linux-omap-2.6.orig/drivers/usb/musb/Kconfig 2008-07-28 10:54:37.000000000 +0530 +++ linux-omap-2.6/drivers/usb/musb/Kconfig 2008-08-12 13:18:34.000000000 +0530 @@ -150,6 +150,14 @@ config USB_INVENTRA_DMA help Enable DMA transfers using Mentor's engine. +config MUSB_USE_SYSTEM_DMA_RX + bool 'Use System DMA for RX endpoints' + depends on USB_MUSB_HDRC && USB_INVENTRA_DMA + help + MUSB RTL version 1.4 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-- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
