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Wed, 3 Nov 2021 08:42:31 +0900 (KST) Received: from epsmtrp2.samsung.com (unknown [182.195.40.14]) by epcas2p3.samsung.com (KnoxPortal) with ESMTPA id 20211102234231epcas2p3b079a93e79767b0dd45e1ee5283e7313~z3z793wnD1956919569epcas2p3g; Tue, 2 Nov 2021 23:42:31 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20211102234231epsmtrp279ef678b0fd2b3aa4ba2f1b8bc3e3b06~z3z781s1J2143521435epsmtrp2O; Tue, 2 Nov 2021 23:42:31 +0000 (GMT) X-AuditID: b6c32a47-489ff7000000271e-39-6181cce77aaf Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 53.1C.29871.7ECC1816; Wed, 3 Nov 2021 08:42:31 +0900 (KST) Received: from perf (unknown [12.36.155.123]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20211102234231epsmtip150d66548013cc8f10d0b8312fe69a03a~z3z7yIEoh3199031990epsmtip1D; Tue, 2 Nov 2021 23:42:31 +0000 (GMT) Date: Wed, 3 Nov 2021 09:09:45 +0900 From: Youngmin Nam To: Mark Rutland Cc: krzysztof.kozlowski@canonical.com, will@kernel.org, daniel.lezcano@linaro.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, pullip.cho@samsung.com, hoony.yu@samsung.com, hajun.sung@samsung.com, myung-su.cha@samsung.com, kgene@kernel.org Subject: Re: [PATCH v2 1/2] clocksource/drivers/exynos_mct_v2: introduce Exynos MCT version 2 driver for next Exynos SoC Message-ID: <20211103000945.GA48132@perf> MIME-Version: 1.0 In-Reply-To: <20211102102802.GA16545@C02TD0UTHF1T.local> User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA02TfUwTZxzHfe7a62EsuVXYnnTONcWMAANapO3hgJnYzE7ZRrJlbiMKFzha 1tLWXpmCJlSmDFBmDXMiAYZDkBHU7SovQRgv5cUFx9sWHU7DYocuMjpCATsn3dqeLv73eX6/ 7zff3/OGo6IBTIznGa20xUgZpNh6XoczShV7//oRSnZsLoas97xElvRNo+ToxXk+edI1j5Lf LXgRknXd4JM/dddiZPXE9wjZdHMKIRtdLQjpqxwApIM9jZJHbyu2CzVt9W1AU2OrxDRsazmm uX2jB9O4x8cFGsf5Ys3nV1qBxsNuTsc/0ifraCqHtkhoY7YpJ8+oTZHufjdzR6ZCKZPHypNI lVRipPLpFKk6LT32jTyDf2Cp5BPKUOAvpVMMI41PTbaYCqy0RGdirClS2pxjMKvMcQyVzxQY tXFG2rpNLpMlKPzCLL3u4dIQzzwNDzqOuwU2MBJWAUJwSCRCz9l5QQVYj4uILgBd5atYoCEi lgCs/es9rrEK4C/lFchTh3PUyecavX6R18HjFncBXK79hx9Q8Ygt0H7UCwKMEbGw45ovyGFE JDzRvew34DhKjCCw951AeSNRBFfZv4MBQiIK9t0ZF3D8HPzh7O+8AIcQJByp/zqoCSciYH/H KBLIhUQPDhf6JjBuOjVsGr7F53gjfDB6RcCxGHrcvU80xbCxownlzHYAv2IXn4i2wpp7nwUH RQkdbGnvCw4K/WlDt3hcORSWOdcEXFkIy0pFnPMV+OiLbwHHm+DVxhaUYw2sbG7AuPPxAOi8 OyCwg5drntlbzTNpHL8KG64uYTXBI3oRXvDhHEbBy93xDYDfCp6nzUy+lmYSzFv/v+xsUz4L gm85emcXqF5YjBsECA4GAcRRaZgQHbZRImEOVVhEW0yZlgIDzQwChf+eTqHi8GyT/zMYrZny xCRZolIpVyUoZCrpC8KkcD0lIrSUldbTtJm2PPUheIjYhpzpTLtWOjs7H8pnt58pxquKE/ec 5rE3i8obl5RZB/bOpA4eifm1q+fEddfcpwvKULUtvnm/5PEoMmV/fZfL1lSlro5c9JXcN6at /Djp+ji39eHkhta6tT8Or1NsmzEbNg2PZR8opPS7Lq6Q3suda38m7YZlVTOvuX0JcW0Zex58 +LO2MqK3qHPanZbBXnj8zURt9L+X3GsZex2H2vUTuoOwpKO9bnnfYQsz5s/rFVxa8d57P9Lk wh+JPcl3zjkm1OpjY5M7y+e86CErPVuYm/tlVlNZ//F19t+cMRELb53bMLU5JrX5Tf2+PmcL wT9Zt2XHfvbtSt/5D/qHnDHLysZSKY/RUfJo1MJQ/wHnc3INVAQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpnkeLIzCtJLcpLzFFi42LZdlhJTvf5mcZEg32n+CzmfZa1aNp/idni +NrXrBb9j18zW2x8+4PJYtPja6wWl3fNYbOYcX4fk8XS6xeZLBY/XsFk8a/3IKPF5k1TmS1a 7pg68HqsmbeG0WNWQy+bx6ZVnWwed67tYfN4d+4cu8fmJfUefVtWMXp83iQXwBHFZZOSmpNZ llqkb5fAlXGri61gkljFs3srWBsY5wt1MXJySAiYSBw+fpi1i5GLQ0hgN6PEnfvLWCESMhK3 V16GsoUl7rccAbOFBB4wSiztigOxWQRUJCa0/GAEsdkEdCW2nfgHZosIqEv07PrCAjKUWeAE k8TxEx1gzcICVRLfNv1kArF5BTQl9t89xw6x+TOjxIQ/15ghEoISJ2c+YQGxmQW0JG78ewnU wAFkS0ss/8cBEuYUsJA4Nm8R2BxRAWWJA9uOM01gFJyFpHsWku5ZCN0LGJlXMUqmFhTnpucW GxYY5qWW6xUn5haX5qXrJefnbmIEx5WW5g7G7as+6B1iZOJgPMQowcGsJMLLfLQhUYg3JbGy KrUoP76oNCe1+BCjNAeLkjjvha6T8UIC6YklqdmpqQWpRTBZJg5OqQam3S4NknyVthdFmU+/ SZfj7yz/4q+uWPz79PNaI+4JwfXzSiaaHq3nluAKWmuzvS309OcUVh57jzXun2c8PbAmWnXL pXUMpRfar+j4nN3VqfJC7tPPfWZSyW/nvvNRuDp1wW3hQI1LbvaTt2+VZSh9JXBYpCZ/edFy 8fc+4T1fv2+TrOmVc99ndCUz4LSxsces6t/7uFItM7Y3Lr+hknVRcPu8N981LJ98t90u6aBm /TN+uiW7tsxR61axGcdS9/y7XtUQdsHYcPHOnjfzunIO6EXcbJdxmNi6VO4hs6TVVsc1d2f8 /ZbkUBzdupjjtbLEI26exeJMwpo1H4+ou+/7/XwO7//yoHsGl3LiWHKVWIozEg21mIuKEwGA uY7dGgMAAA== X-CMS-MailID: 20211102234231epcas2p3b079a93e79767b0dd45e1ee5283e7313 X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----ZBuuKJqGqetWuXeXLn-uUmRQxt4bB4GzF80pTq2gGxc9tq5b=_ae3f7_" X-Sendblock-Type: AUTO_CONFIDENTIAL CMS-TYPE: 102P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20211101234500epcas2p2d0e5bc54615b635f6694bc1be4c89fb5 References: <20211102001122.27516-1-youngmin.nam@samsung.com> <20211102001122.27516-2-youngmin.nam@samsung.com> <20211102102802.GA16545@C02TD0UTHF1T.local> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211102_164256_427214_B2E13420 X-CRM114-Status: GOOD ( 29.22 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org ------ZBuuKJqGqetWuXeXLn-uUmRQxt4bB4GzF80pTq2gGxc9tq5b=_ae3f7_ Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline On Tue, Nov 02, 2021 at 10:28:10AM +0000, Mark Rutland wrote: > On Tue, Nov 02, 2021 at 09:11:21AM +0900, Youngmin Nam wrote: > > Exynos MCT version 2 is composed of 1 FRC and 12 comparators. > > There are no global timer and local timer anymore. > > The 1 of 64bit FRC serves as "up-counter"(not "comparators"). > > The 12 comaprators(not "counter") can be used as per-cpu event timer > > so that it can support upto 12 cores. > > And a RTC source can be used as backup clock source. > > [...] > > > +static int exynos_mct_starting_cpu(unsigned int cpu) > > +{ > > + struct mct_clock_event_device *mevt = per_cpu_ptr(&percpu_mct_tick, cpu); > > + struct clock_event_device *evt = &mevt->evt; > > + > > + snprintf(mevt->name, sizeof(mevt->name), "mct_comp%d", cpu); > > + > > + evt->name = mevt->name; > > + evt->cpumask = cpumask_of(cpu); > > + evt->set_next_event = exynos_comp_set_next_event; > > + evt->set_state_periodic = mct_set_state_periodic; > > + evt->set_state_shutdown = mct_set_state_shutdown; > > + evt->set_state_oneshot = mct_set_state_shutdown; > > + evt->set_state_oneshot_stopped = mct_set_state_shutdown; > > + evt->tick_resume = mct_set_state_shutdown; > > + evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; > > + evt->rating = 500; /* use value higher than ARM arch timer */ > > Previously Will asked you to try CLOCK_EVT_FEAT_PERCPU here, and to set > the C3STOP flag on the arch timer via the DT when necessary, rather than > trying to override the arch timer like this: > > https://protect2.fireeye.com/v1/url?k=72526080-2dc9598b-7253ebcf-002590f5b904-ca603717c6462908&q=1&e=be56aa83-dbac-4639-913d-d388620fe3fc&u=https%3A%2F%2Flore.kernel.org%2Fr%2F20211027073458.GA22231%40willie-the-truck > > There are a bunch of things that depend on the architected timer working > as a clocksource (e.g. vdso, kvm), and it *should* work as a lock > clockevent_device if configured correctly, and it's much more consistent > with *everyone else* to use the arhcitected timer by default. > > Please try as Will suggested above, so that this works from day one. > > Thanks, > Mark. > Hi Mark. It looks like you missed my previous mail. https://lore.kernel.org/all/20211029035422.GA30523@perf/#t Yes, I believe Will's suggestion definitely will work. But that is for performance not functionality. As a driver for new H/W IP I would like to confirm functionality first. We need more time to test this feature with our exynos core power down feature. And we need to do a various regression test whether there is another corner case or not. So, how about we apply Will's suggetion later after the current patchset is merged first? After doing our regression test with our exynos core power down feature, we can confirm this. Thanks. ------ZBuuKJqGqetWuXeXLn-uUmRQxt4bB4GzF80pTq2gGxc9tq5b=_ae3f7_ Content-Type: text/plain; charset="utf-8" ------ZBuuKJqGqetWuXeXLn-uUmRQxt4bB4GzF80pTq2gGxc9tq5b=_ae3f7_ Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ------ZBuuKJqGqetWuXeXLn-uUmRQxt4bB4GzF80pTq2gGxc9tq5b=_ae3f7_--