From d748c9810be2d6a570aad0390463c9ac4336b161 Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 11 Jan 2017 10:16:58 +0000 Subject: [PATCH] rtc: armada38x: make struct rtc_class_ops const Armada38x wants to modify its rtc_class_ops to remove the interrupt handling when there is no usable interrupt, but this means we leave function pointers in writable memory. Since rtc_class_ops is small, arrange to have two instances, one for when we have interrupts, and one for when we have none, both marked const. This allows the compiler to place them in read-only memory, which is better than placing them in __ro_after_init. Thanks to Bhumika Goyal for pointing out that the structure was writable and submitting a patch to add __ro_after_init. Signed-off-by: Russell King Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-armada38x.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/drivers/rtc/rtc-armada38x.c b/drivers/rtc/rtc-armada38x.c index bc823700a9fe..7cb5b27189db 100644 --- a/drivers/rtc/rtc-armada38x.c +++ b/drivers/rtc/rtc-armada38x.c @@ -262,7 +262,7 @@ static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data) return IRQ_HANDLED; } -static struct rtc_class_ops armada38x_rtc_ops = { +static const struct rtc_class_ops armada38x_rtc_ops = { .read_time = armada38x_rtc_read_time, .set_time = armada38x_rtc_set_time, .read_alarm = armada38x_rtc_read_alarm, @@ -270,8 +270,15 @@ static struct rtc_class_ops armada38x_rtc_ops = { .alarm_irq_enable = armada38x_rtc_alarm_irq_enable, }; +static const struct rtc_class_ops armada38x_rtc_ops_noirq = { + .read_time = armada38x_rtc_read_time, + .set_time = armada38x_rtc_set_time, + .read_alarm = armada38x_rtc_read_alarm, +}; + static __init int armada38x_rtc_probe(struct platform_device *pdev) { + const struct rtc_class_ops *ops; struct resource *res; struct armada38x_rtc *rtc; int ret; @@ -307,22 +314,25 @@ static __init int armada38x_rtc_probe(struct platform_device *pdev) 0, pdev->name, rtc) < 0) { dev_warn(&pdev->dev, "Interrupt not available.\n"); rtc->irq = -1; + } + platform_set_drvdata(pdev, rtc); + + if (rtc->irq != -1) { + device_init_wakeup(&pdev->dev, 1); + ops = &armada38x_rtc_ops; + } else { /* * If there is no interrupt available then we can't * use the alarm */ - armada38x_rtc_ops.set_alarm = NULL; - armada38x_rtc_ops.alarm_irq_enable = NULL; + ops = &armada38x_rtc_ops_noirq; } - platform_set_drvdata(pdev, rtc); - if (rtc->irq != -1) - device_init_wakeup(&pdev->dev, 1); /* Update RTC-MBUS bridge timing parameters */ rtc_update_mbus_timing_params(rtc); rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name, - &armada38x_rtc_ops, THIS_MODULE); + ops, THIS_MODULE); if (IS_ERR(rtc->rtc_dev)) { ret = PTR_ERR(rtc->rtc_dev); dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret); -- 2.39.5