From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel.lezcano@linaro.org (Daniel Lezcano) Date: Mon, 28 Apr 2014 13:25:00 +0200 Subject: [PATCH v3 6/6] arm: exynos: Add /dev/bL_status user interface on Exynos5420 In-Reply-To: <1398528348-21214-7-git-send-email-a.kesavan@samsung.com> References: <1398528348-21214-1-git-send-email-a.kesavan@samsung.com> <1398528348-21214-7-git-send-email-a.kesavan@samsung.com> Message-ID: <535E3A8C.6070304@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/26/2014 06:05 PM, Abhilash Kesavan wrote: > Add a user interface to check the core and cluster status on > Exynos5420. This can be utilized while debugging mcpm issues. > cat /dev/bL_status will show the current power status of all > the 8 cores along with the cluster. > > Signed-off-by: Thomas Abraham > Signed-off-by: Inderpal Singh > Signed-off-by: Andrew Bresticker > Signed-off-by: Abhilash Kesavan > --- Hi Abhilash, I don't think you should add this file. 1. big Little is not exynos specific 2. /dev is not for the purpose of your patch So I would recommend: 1. create a generic infra-structure for all the big.Little 2. and/or use debugfs Furthermore, how is it usable ? Will you read the file every 2ms to check the cluster status, knowing it will be woken up by the read operation ? Frankly speaking, it would make sense to add traces in mcpm.c (if they aren't already there - did not check). > arch/arm/mach-exynos/mcpm-exynos.c | 64 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 64 insertions(+) > > diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c > index f9977bf..83428b0 100644 > --- a/arch/arm/mach-exynos/mcpm-exynos.c > +++ b/arch/arm/mach-exynos/mcpm-exynos.c > @@ -269,6 +269,53 @@ static void __init exynos_mcpm_usage_count_init(void) > cpu_use_count[cpu][cluster] = 1; > } > > +static size_t bL_check_status(char *info) > +{ > + size_t len = 0; > + int i; > + > + len += sprintf(&info[len], "\t0 1 2 3 L2\n"); > + len += sprintf(&info[len], "[A15] "); > + for (i = 0; i < 4; i++) { > + len += sprintf(&info[len], "%d ", > + (readl(EXYNOS_ARM_CORE_STATUS(i)) & 0x3) == 3 ? 1 : 0); > + } > + len += sprintf(&info[len], "%d\n", > + (readl(EXYNOS_COMMON_STATUS(0)) & 0x3) == 3 ? 1 : 0); > + > + len += sprintf(&info[len], "[A7] "); > + for (i = 4; i < 8; i++) > + len += sprintf(&info[len], "%d ", > + (readl(EXYNOS_ARM_CORE_STATUS(i)) & 0x3) == 3 ? 1 : 0); > + len += sprintf(&info[len], "%d\n\n", > + (readl(EXYNOS_COMMON_STATUS(1)) & 0x3) == 3 ? 1 : 0); > + > + return len; > +} > + > +static ssize_t bL_status_read(struct file *file, char __user *buf, > + size_t len, loff_t *pos) > +{ > + size_t count = 0; > + char info[100]; > + > + count = bL_check_status(info); > + if (count < 0) > + return -EINVAL; > + > + return simple_read_from_buffer(buf, len, pos, info, count); > +} > + > +static const struct file_operations bL_status_fops = { > + .read = bL_status_read, > +}; > + > +static struct miscdevice bL_status_device = { > + MISC_DYNAMIC_MINOR, > + "bL_status", > + &bL_status_fops > +}; > + > /* > * Enable cluster-level coherency, in preparation for turning on the MMU. > */ > @@ -319,3 +366,20 @@ static int __init exynos_mcpm_init(void) > } > > early_initcall(exynos_mcpm_init); > + > +static int __init exynos_bl_status_init(void) > +{ > + int ret; > + > + if (!soc_is_exynos5420()) > + return -ENODEV; > + > + ret = misc_register(&bL_status_device); > + if (ret) { > + pr_info("bl_status not available\n"); > + return ret; > + } > + return 0; > +} > + > +late_initcall(exynos_bl_status_init); > -- Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog