msm8916平臺Linux watchdog詳解(2)

2019-11-09 18:29:55

字體：大中小

來源：轉載

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介紹高通msm8916中CONFIG_MSM_WATCHDOG_V2宏打開之后，watchdog是怎么工作的。這個watchdog跟硬件相關，主要檢查當前是否有頻繁的中斷發生導致整個內核調度都出現問題。[LOCKUP_DETECTOR與MSM_WATCHDOG_V2的區別？]

這個宏很簡單，所涉及的文件就只有一個drivers/soc/qcom/watchdog_v2.c文件。相關的device tree定義如下

qcom,wdt@b017000 { compatible = "qcom,msm-watchdog"; reg = <0xb017000 0x1000>; reg-names = "wdt-base"; interrupts = <0 3 0>, <0 4 0>; qcom,bark-time = <20000>; //bark時間20秒，20秒之內沒有喂狗，會觸發中斷 qcom,pet-time = <10000>;//pet時間10秒，表示每10秒喂一次狗 qcom,ipi-ping; };

這個device tree內容在下面函數里邊解析，下面內容可以看一下驅動里邊是怎么操作resource地址空間的！！！

(1) devm_request_mem_region()[iomem_resource](2) pdata->base = devm_ioremap(&pdev->dev, pdata->phys_base, pdata->size);static int msm_wdog_dt_to_pdata(struct platform_device *pdev, struct msm_watchdog_data *pdata){ struct device_node *node = pdev->dev.of_node; struct resource *res; int ret; res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "wdt-base"); if (!res) return -ENODEV; pdata->size = resource_size(res); pdata->phys_base = res->start; if (unlikely(!(devm_request_mem_region(&pdev->dev, pdata->phys_base, pdata->size, "msm-watchdog")))) { dev_err(&pdev->dev, "%s cannot reserve watchdog region/n", __func__); return -ENXIO; } pdata->base = devm_ioremap(&pdev->dev, pdata->phys_base, pdata->size); if (!pdata->base) { dev_err(&pdev->dev, "%s cannot map wdog register space/n", __func__); return -ENXIO; }#ifdef CONFIG_SEC_DEBUG wdog_base_addr = pdata->base;#endif res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "wdt-absent-base"); if (res) { pdata->wdog_absent_base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); if (!pdata->wdog_absent_base) { dev_err(&pdev->dev, "cannot map wdog absent register space/n"); return -ENXIO; } } else { dev_info(&pdev->dev, "wdog absent resource not 下面是probe函數

static int msm_watchdog_probe(struct platform_device *pdev){ int ret; struct msm_watchdog_data *wdog_dd; wdog_wq = alloc_workqueue("wdog", WQ_HIGHPRI, 0);//初始化一個workqueue if (!wdog_wq) { pr_err("Failed to allocate watchdog workqueue/n"); return -EIO; } if (!pdev->dev.of_node || !enable) return -ENODEV; wdog_dd = kzalloc(sizeof(struct msm_watchdog_data), GFP_KERNEL); if (!wdog_dd) return -EIO; ret = msm_wdog_dt_to_pdata(pdev, wdog_dd); if (ret) goto err; wdog_data = wdog_dd; wdog_dd->dev = &pdev->dev; platform_set_drvdata(pdev, wdog_dd); cpumask_clear(&wdog_dd->alive_mask); INIT_WORK(&wdog_dd->init_dogwork_struct, init_watchdog_work); INIT_DELAYED_WORK(&wdog_dd->dogwork_struct, pet_watchdog_work); queue_work(wdog_wq, &wdog_dd->init_dogwork_struct); //上面初始化了兩個work，然后queue進去init_dogwork_struct這個work //這里queue進入是否會馬上調度執行？？需要仔細看一下workqueue相關內容 return 0;err: destroy_workqueue(wdog_wq); kzfree(wdog_dd); return ret;}