/* * OHCI HCD (Host Controller Driver) for USB. * * (C) Copyright 1999 Roman Weissgaerber * (C) Copyright 2000-2005 David Brownell * (C) Copyright 2002 Hewlett-Packard Company * (C) Copyright 2008 Magnus Damm * * SM501 Bus Glue - based on ohci-omap.c * * This file is licenced under the GPL. */ #include #include #include #include #include #include static int ohci_sm501_init(struct usb_hcd *hcd) { return ohci_init(hcd_to_ohci(hcd)); } static int ohci_sm501_start(struct usb_hcd *hcd) { struct device *dev = hcd->self.controller; int ret; ret = ohci_run(hcd_to_ohci(hcd)); if (ret < 0) { dev_err(dev, "can't start %s", hcd->self.bus_name); ohci_stop(hcd); } return ret; } /*-------------------------------------------------------------------------*/ static const struct hc_driver ohci_sm501_hc_driver = { .description = hcd_name, .product_desc = "SM501 OHCI", .hcd_priv_size = sizeof(struct ohci_hcd), /* * generic hardware linkage */ .irq = ohci_irq, .flags = HCD_USB11 | HCD_MEMORY | HCD_LOCAL_MEM, /* * basic lifecycle operations */ .reset = ohci_sm501_init, .start = ohci_sm501_start, .stop = ohci_stop, .shutdown = ohci_shutdown, /* * managing i/o requests and associated device resources */ .urb_enqueue = ohci_urb_enqueue, .urb_dequeue = ohci_urb_dequeue, .endpoint_disable = ohci_endpoint_disable, /* * scheduling support */ .get_frame_number = ohci_get_frame, /* * root hub support */ .hub_status_data = ohci_hub_status_data, .hub_control = ohci_hub_control, #ifdef CONFIG_PM .bus_suspend = ohci_bus_suspend, .bus_resume = ohci_bus_resume, #endif .start_port_reset = ohci_start_port_reset, }; /*-------------------------------------------------------------------------*/ static int ohci_hcd_sm501_drv_probe(struct platform_device *pdev) { const struct hc_driver *driver = &ohci_sm501_hc_driver; struct device *dev = &pdev->dev; struct resource *res, *mem; int retval, irq; struct usb_hcd *hcd = NULL; irq = retval = platform_get_irq(pdev, 0); if (retval < 0) goto err0; mem = platform_get_resource(pdev, IORESOURCE_MEM, 1); if (mem == NULL) { dev_err(dev, "no resource definition for memory\n"); retval = -ENOENT; goto err0; } if (!request_mem_region(mem->start, resource_size(mem), pdev->name)) { dev_err(dev, "request_mem_region failed\n"); retval = -EBUSY; goto err0; } /* The sm501 chip is equipped with local memory that may be used * by on-chip devices such as the video controller and the usb host. * This driver uses dma_declare_coherent_memory() to make sure * usb allocations with dma_alloc_coherent() allocate from * this local memory. The dma_handle returned by dma_alloc_coherent() * will be an offset starting from 0 for the first local memory byte. * * So as long as data is allocated using dma_alloc_coherent() all is * fine. This is however not always the case - buffers may be allocated * using kmalloc() - so the usb core needs to be told that it must copy * data into our local memory if the buffers happen to be placed in * regular memory. The HCD_LOCAL_MEM flag does just that. */ if (!dma_declare_coherent_memory(dev, mem->start, mem->start - mem->parent->start, resource_size(mem), DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE)) { dev_err(dev, "cannot declare coherent memory\n"); retval = -ENXIO; goto err1; } /* allocate, reserve and remap resources for registers */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res == NULL) { dev_err(dev, "no resource definition for registers\n"); retval = -ENOENT; goto err2; } hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev)); if (!hcd) { retval = -ENOMEM; goto err2; } hcd->rsrc_start = res->start; hcd->rsrc_len = resource_size(res); if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, pdev->name)) { dev_err(dev, "request_mem_region failed\n"); retval = -EBUSY; goto err3; } hcd->regs = ioremap(hcd->rsrc_start, hcd->rsrc_len); if (hcd->regs == NULL) { dev_err(dev, "cannot remap registers\n"); retval = -ENXIO; goto err4; } ohci_hcd_init(hcd_to_ohci(hcd)); retval = usb_add_hcd(hcd, irq, IRQF_SHARED); if (retval) goto err5; device_wakeup_enable(hcd->self.controller); /* enable power and unmask interrupts */ sm501_unit_power(dev->parent, SM501_GATE_USB_HOST, 1); sm501_modify_reg(dev->parent, SM501_IRQ_MASK, 1 << 6, 0); return 0; err5: iounmap(hcd->regs); err4: release_mem_region(hcd->rsrc_start, hcd->rsrc_len); err3: usb_put_hcd(hcd); err2: dma_release_declared_memory(dev); err1: release_mem_region(mem->start, resource_size(mem)); err0: return retval; } static int ohci_hcd_sm501_drv_remove(struct platform_device *pdev) { struct usb_hcd *hcd = platform_get_drvdata(pdev); struct resource *mem; usb_remove_hcd(hcd); release_mem_region(hcd->rsrc_start, hcd->rsrc_len); usb_put_hcd(hcd); dma_release_declared_memory(&pdev->dev); mem = platform_get_resource(pdev, IORESOURCE_MEM, 1); if (mem) release_mem_region(mem->start, resource_size(mem)); /* mask interrupts and disable power */ sm501_modify_reg(pdev->dev.parent, SM501_IRQ_MASK, 0, 1 << 6); sm501_unit_power(pdev->dev.parent, SM501_GATE_USB_HOST, 0); return 0; } /*-------------------------------------------------------------------------*/ #ifdef CONFIG_PM static int ohci_sm501_suspend(struct platform_device *pdev, pm_message_t msg) { struct device *dev = &pdev->dev; struct usb_hcd *hcd = platform_get_drvdata(pdev); struct ohci_hcd *ohci = hcd_to_ohci(hcd); bool do_wakeup = device_may_wakeup(dev); int ret; if (time_before(jiffies, ohci->next_statechange)) msleep(5); ohci->next_statechange = jiffies; ret = ohci_suspend(hcd, do_wakeup); if (ret) return ret; sm501_unit_power(dev->parent, SM501_GATE_USB_HOST, 0); return ret; } static int ohci_sm501_resume(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct usb_hcd *hcd = platform_get_drvdata(pdev); struct ohci_hcd *ohci = hcd_to_ohci(hcd); if (time_before(jiffies, ohci->next_statechange)) msleep(5); ohci->next_statechange = jiffies; sm501_unit_power(dev->parent, SM501_GATE_USB_HOST, 1); ohci_resume(hcd, false); return 0; } #else #define ohci_sm501_suspend NULL #define ohci_sm501_resume NULL #endif /*-------------------------------------------------------------------------*/ /* * Driver definition to register with the SM501 bus */ static struct platform_driver ohci_hcd_sm501_driver = { .probe = ohci_hcd_sm501_drv_probe, .remove = ohci_hcd_sm501_drv_remove, .shutdown = usb_hcd_platform_shutdown, .suspend = ohci_sm501_suspend, .resume = ohci_sm501_resume, .driver = { .name = "sm501-usb", }, }; MODULE_ALIAS("platform:sm501-usb"); mmc_flush_cache command to complete: .. [ 240.251595] INFO: task mmcqd/1:52 blocked for more than 120 seconds. [ 240.257973] Not tainted 4.1.13-00510-g9d91424 #2 [ 240.263109] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 240.270955] mmcqd/1 D c047504c 0 52 2 0x00000000 [ 240.277359] [<c047504c>] (__schedule) from [<c04754a0>] (schedule+0x40/0x98) [ 240.284418] [<c04754a0>] (schedule) from [<c0477d40>] (schedule_timeout+0x148/0x188) [ 240.292191] [<c0477d40>] (schedule_timeout) from [<c0476040>] (wait_for_common+0xa4/0x170) [ 240.300491] [<c0476040>] (wait_for_common) from [<c02efc1c>] (mmc_wait_for_req_done+0x4c/0x13c) [ 240.309224] [<c02efc1c>] (mmc_wait_for_req_done) from [<c02efd90>] (mmc_wait_for_cmd+0x64/0x84) [ 240.317953] [<c02efd90>] (mmc_wait_for_cmd) from [<c02f5b14>] (__mmc_switch+0xa4/0x2a8) [ 240.325964] [<c02f5b14>] (__mmc_switch) from [<c02f5d40>] (mmc_switch+0x28/0x30) [ 240.333389] [<c02f5d40>] (mmc_switch) from [<c02f0984>] (mmc_flush_cache+0x54/0x80) [ 240.341073] [<c02f0984>] (mmc_flush_cache) from [<c02ff0c4>] (mmc_blk_issue_rq+0x114/0x4e8) [ 240.349459] [<c02ff0c4>] (mmc_blk_issue_rq) from [<c03008d4>] (mmc_queue_thread+0xc0/0x180) [ 240.357844] [<c03008d4>] (mmc_queue_thread) from [<c003cf90>] (kthread+0xdc/0xf4) [ 240.365339] [<c003cf90>] (kthread) from [<c0010068>] (ret_from_fork+0x14/0x2c) .. .. [ 240.664311] INFO: task partprobe:564 blocked for more than 120 seconds. [ 240.670943] Not tainted 4.1.13-00510-g9d91424 #2 [ 240.676078] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 240.683922] partprobe D c047504c 0 564 486 0x00000000 [ 240.690318] [<c047504c>] (__schedule) from [<c04754a0>] (schedule+0x40/0x98) [ 240.697396] [<c04754a0>] (schedule) from [<c0477d40>] (schedule_timeout+0x148/0x188) [ 240.705149] [<c0477d40>] (schedule_timeout) from [<c0476040>] (wait_for_common+0xa4/0x170) [ 240.713446] [<c0476040>] (wait_for_common) from [<c01f3300>] (submit_bio_wait+0x58/0x64) [ 240.721571] [<c01f3300>] (submit_bio_wait) from [<c01fbbd8>] (blkdev_issue_flush+0x60/0x88) [ 240.729957] [<c01fbbd8>] (blkdev_issue_flush) from [<c010ff84>] (blkdev_fsync+0x34/0x44) [ 240.738083] [<c010ff84>] (blkdev_fsync) from [<c0109594>] (do_fsync+0x3c/0x64) [ 240.745319] [<c0109594>] (do_fsync) from [<c000ffc0>] (ret_fast_syscall+0x0/0x3c) .. Here is the detailed sequence showing when this issue may happen: 1) At probe time, mmci device is initialized and card busy detection based on DAT[0] monitoring is enabled. 2) Later during run time, since card reported to support internal caches, a MMCI_SWITCH command is sent to eMMC device with FLUSH_CACHE operation. On receiving this command, eMMC may enter busy state (for a relatively short time in the case of the dead-lock). 3) Then mmci interrupt is raised and mmci_irq() is called: MMCISTATUS register is read and is equal to 0x01000440. So the following status bits are set: - MCI_CMDRESPEND (= 6) - MCI_DATABLOCKEND (= 10) - MCI_ST_CARDBUSY (= 24) Since MMCIMASK0 register is 0x3FF, status variable is set to 0x00000040 and BIT MCI_CMDRESPEND is cleared by writing MMCICLEAR register. Then mmci_cmd_irq() is called. Considering the following conditions: - host->busy_status is 0, - this is a "busy response", - reading again MMCISTATUS register gives 0x1000400, MMCIMASK0 is updated to unmask MCI_ST_BUSYEND bit. Thus, MMCIMASK0 is set to 0x010003FF and host->busy_status is set to wait for busy end completion. Back again in status loop of mmci_irq(), we quickly go through mmci_data_irq() as there are no data in that case. And we finally go through following test at the end of while(status) loop: /* * Don't poll for busy completion in irq context. */ if (host->variant->busy_detect && host->busy_status) status &= ~host->variant->busy_detect_flag; Because status variable is not yet null (is equal to 0x40), we do not leave interrupt context yet but we loop again into while(status) loop. So we run across following steps: a) MMCISTATUS register is read again and this time is equal to 0x01000400. So that following bits are set: - MCI_DATABLOCKEND (= 10) - MCI_ST_CARDBUSY (= 24) Since MMCIMASK0 register is equal to 0x010003FF: b) status variable is set to 0x01000000. c) MCI_ST_CARDBUSY bit is cleared by writing MMCICLEAR register. Then, mmci_cmd_irq() is called one more time. Since host->busy_status is set and that MCI_ST_CARDBUSY is set in status variable, we just return from this function. Back again in mmci_irq(), status variable is set to 0 and we finally leave the while(status) loop. As a result we leave interrupt context, waiting for busy end interrupt event. Now, consider that busy end completion is raised IN BETWEEN steps 3.a) and 3.c). In such a case, we may mistakenly clear busy end interrupt at step 3.c) while it has not yet been processed. This will result in mmc command to wait forever for a busy end completion that will never happen. To fix the problem, this patch implements the following changes: Considering that the mmci seems to be triggering the IRQ on both edges while monitoring DAT0 for busy completion and that same status bit is used to monitor start and end of busy detection, special care must be taken to make sure that both start and end interrupts are always cleared one after the other. 1) Clearing of card busy bit is moved in mmc_cmd_irq() function where unmasking of busy end bit is effectively handled. 2) Just before unmasking busy end event, busy start event is cleared by writing card busy bit in MMCICLEAR register. 3) Finally, once we are no more busy with a command, busy end event is cleared writing again card busy bit in MMCICLEAR register. This patch has been tested with the ST Accordo5 machine, not yet supported upstream but relies on the mmci driver. Signed-off-by: Sarang Mairal <sarang.mairal@garmin.com> Signed-off-by: Jean-Nicolas Graux <jean-nicolas.graux@st.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/usb/core/driver.c')