Hello Shawn, > -----Original Message----- > From: Shawn Lin [mailto:shawn.lin@xxxxxxxxxxxxxx] > Sent: Tuesday, June 21, 2016 10:52 AM > To: Seung-Woo Kim; jh80.chung@xxxxxxxxxxx; ulf.hansson@xxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Cc: shawn.lin@xxxxxxxxxxxxxx > Subject: Re: mmc: dw_mmc: warning with CONFIG_DMA_API_DEBUG > > On 2016/6/20 16:34, Seung-Woo Kim wrote: > > Hi folks, > > > > During booting test on my Exynos5422 based Odroid-XU3, kernel compiled > > with CONFIG_DMA_API_DEBUG reported following warning: > > > > ------------[ cut here ]------------ > > WARNING: CPU: 0 PID: 0 at lib/dma-debug.c:1096 check_unmap+0x7bc/0xb38 > > dwmmc_exynos 12200000.mmc: DMA-API: device driver tries to free DMA memory it has not allocated [device > address=0x000000006d9d2200] > > Thanks for this report and fix. > > DTO(the same as IDMAC-RI/TI) interrupts may or may not come together > with DATA_ERR. If DATA_ERR occur without geting DTO, we should issue > CMD12 manually to generate DTO. It's a ugly deisgn for dwmmc but from > the vendor's ask. > > So you should never think we complete the xfer without > checking DATA_ERR. This way you got the warning. > > So could you try this one: With your patch, there is no more the DMA API waring in my environment. Best Regards, - Seung-Woo Kim > > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -2474,7 +2474,8 @@ static irqreturn_t dw_mci_interrupt(int irq, void > *dev_id) > mci_writel(host, IDSTS64, SDMMC_IDMAC_INT_TI | > > SDMMC_IDMAC_INT_RI); > mci_writel(host, IDSTS64, SDMMC_IDMAC_INT_NI); > - host->dma_ops->complete((void *)host); > + if (!test_bit(EVENT_DATA_ERROR, > &host->pending_events)) > + host->dma_ops->complete((void *)host); > } > } else { > pending = mci_readl(host, IDSTS); > @@ -2482,7 +2483,8 @@ static irqreturn_t dw_mci_interrupt(int irq, void > *dev_id) > mci_writel(host, IDSTS, SDMMC_IDMAC_INT_TI | > > SDMMC_IDMAC_INT_RI); > mci_writel(host, IDSTS, SDMMC_IDMAC_INT_NI); > - host->dma_ops->complete((void *)host); > + if (!test_bit(EVENT_DATA_ERROR, > &host->pending_events)) > + host->dma_ops->complete((void *)host); > } > } > > > > [size=128 bytes] > > Modules linked in: > > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc4 #26 > > Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) > > [<c0112b4c>] (unwind_backtrace) from [<c010d888>] (show_stack+0x20/0x24) > > [<c010d888>] (show_stack) from [<c03fab0c>] (dump_stack+0x80/0x94) > > [<c03fab0c>] (dump_stack) from [<c0123548>] (__warn+0xf8/0x110) > > [<c0123548>] (__warn) from [<c01235a8>] (warn_slowpath_fmt+0x48/0x50) > > [<c01235a8>] (warn_slowpath_fmt) from [<c042ac90>] (check_unmap+0x7bc/0xb38) > > [<c042ac90>] (check_unmap) from [<c042b25c>] (debug_dma_unmap_sg+0x118/0x148) > > [<c042b25c>] (debug_dma_unmap_sg) from [<c077512c>] (dw_mci_dma_cleanup+0x7c/0xb8) > > [<c077512c>] (dw_mci_dma_cleanup) from [<c0773f24>] (dw_mci_stop_dma+0x40/0x50) > > [<c0773f24>] (dw_mci_stop_dma) from [<c0777d04>] (dw_mci_tasklet_func+0x130/0x3b4) > > [<c0777d04>] (dw_mci_tasklet_func) from [<c0129760>] (tasklet_action+0xb4/0x150) > > [<c0129760>] (tasklet_action) from [<c0101674>] (__do_softirq+0xe4/0x3cc) > > [<c0101674>] (__do_softirq) from [<c0129030>] (irq_exit+0xd0/0x10c) > > [<c0129030>] (irq_exit) from [<c01778a0>] (__handle_domain_irq+0x90/0xfc) > > [<c01778a0>] (__handle_domain_irq) from [<c0101548>] (gic_handle_irq+0x64/0xa8) > > [<c0101548>] (gic_handle_irq) from [<c010e3d4>] (__irq_svc+0x54/0x90) > > Exception stack(0xc1101ef8 to 0xc1101f40) > > 1ee0: 00000001 00000000 > > 1f00: 00000000 c011b600 c1100000 c110753c 00000000 c11c3984 c11074d4 c1107548 > > 1f20: 00000000 c1101f54 c1101f58 c1101f48 c010a1fc c010a200 60000013 ffffffff > > [<c010e3d4>] (__irq_svc) from [<c010a200>] (arch_cpu_idle+0x48/0x4c) > > [<c010a200>] (arch_cpu_idle) from [<c01669d8>] (default_idle_call+0x30/0x3c) > > [<c01669d8>] (default_idle_call) from [<c0166d3c>] (cpu_startup_entry+0x358/0x3b4) > > [<c0166d3c>] (cpu_startup_entry) from [<c0aa6ab8>] (rest_init+0x94/0x98) > > [<c0aa6ab8>] (rest_init) from [<c1000d58>] (start_kernel+0x3a4/0x3b0) > > [<c1000d58>] (start_kernel) from [<4000807c>] (0x4000807c) > > ---[ end trace 256f83eed365daf0 ]--- > > > > The warning occurs because after complete callback function, > > dw_mci_dmac_complete_dma() is called, then dw_mci_stop_dma() is called > > again. So it causes dma_unmap_sg() is called twice for same sg. It > > occurs during clock setting at booting time. > > > > Simply, clearing host->using_dma flag on dw_mci_dmac_complete_dma() and > > dw_mci_stop_dma() like following fixes the issue, but I am not sure > > this approach is proper. > > --- > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > > index 2cc6123..a71c94b 100644 > > --- a/drivers/mmc/host/dw_mmc.c > > +++ b/drivers/mmc/host/dw_mmc.c > > @@ -388,6 +388,7 @@ static void dw_mci_stop_dma(struct dw_mci *host) > > if (host->using_dma) { > > host->dma_ops->stop(host); > > host->dma_ops->cleanup(host); > > + host->using_dma = 0; > > } > > > > /* Data transfer was stopped by the interrupt handler */ > > @@ -455,6 +456,7 @@ static void dw_mci_dmac_complete_dma(void *arg) > > DMA_FROM_DEVICE); > > > > host->dma_ops->cleanup(host); > > + host->using_dma = 0; > > > > /* > > * If the card was removed, data will be NULL. No point in trying to > > @@ -943,8 +945,6 @@ static int dw_mci_submit_data_dma(struct dw_mci *host, struct mmc_data *data) > > int sg_len; > > u32 temp; > > > > - host->using_dma = 0; > > - > > /* If we don't have a channel, we can't do DMA */ > > if (!host->use_dma) > > return -ENODEV; > > --- > > > > Best Regards, > > - Seung-Woo Kim > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > -- > Best Regards > Shawn Lin > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
