From: Priit Laes <plaes@plaes.org> To: Maxime Ripard <maxime.ripard@bootlin.com> Cc: Chen-Yu Tsai <wens@csie.org>, Michael Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@kernel.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, linux-clk <linux-clk@vger.kernel.org>, linux-kernel <linux-kernel@vger.kernel.org>, Jernej Skrabec <jernej.skrabec@siol.net> Subject: Re: [RFC PATCH] clk: sunxi-ng: sun4i: Use CLK_SET_RATE_PARENT for mmc2 clock Date: Mon, 11 Feb 2019 14:35:52 +0000 [thread overview] Message-ID: <20190211143552.2uqx6yy53dyv5lbl@plaes.org> (raw) In-Reply-To: <20190206155227.wbkzvsdgykir4wn5@flea> On Wed, Feb 06, 2019 at 04:52:27PM +0100, Maxime Ripard wrote: > Hi, > > On Wed, Feb 06, 2019 at 10:03:09AM +0000, Priit Laes wrote: > > > > I'm concerned for other users of the PLL-PERIPH clock. AFAIK > > > > all of them, except the HRTIMER, expect the clock rate to stay > > > > the same and not change underneath them. And SATA expects it to > > > > be at 600 MHz, as the datasheet says. And while it may not directly > > > > apply to the LIME2, eMMC on newer SoCs / boards run at the slightly > > > > reduced rate of 50 MHz just fine. > > > > > > > > In the commit in question, clocks without CLK_SET_RATE_PARENT > > > > should be using the old code (now in the if conditional block), > > > > i.e. the behavior should not have changed. > > > > > > > > I don't think this actually "fixes" whatever bug was introduced, > > > > but only papers over the issue, and possible introduces further > > > > issues for other users. > > > > > > You're right, I've overlooked that it was pll-periph being > > > affected. I've dropped it for now. > > > > Any ideas what could be done. I currently have no time to debug it, > > but it affects existing systems. > > I can't find what would change with that commit either if the flag > isn't set, so looking at the register state before and after that > commit would help I guess? Register dump without the patch: $ busybox devmem 0x01c20090 0x0250030E pll-ddr-base 2 2 0 768000000 0 0 50000 pll-ddr-other 1 1 0 768000000 0 0 50000 mmc2 3 3 0 51200000 0 0 50000 Register dump with patch applied, booted from mmc0 and after mounting emmc: $ busybox devmem 0x01c20090 0x8140020B pll-periph-base 3 3 0 1200000000 0 0 50000 pll-periph 6 6 0 600000000 0 0 50000 mmc2 3 3 0 50000000 0 0 50000 > > Maxime > > -- > Maxime Ripard, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com
WARNING: multiple messages have this Message-ID (diff)
From: Priit Laes <plaes@plaes.org> To: Maxime Ripard <maxime.ripard@bootlin.com> Cc: Jernej Skrabec <jernej.skrabec@siol.net>, Stephen Boyd <sboyd@kernel.org>, Michael Turquette <mturquette@baylibre.com>, linux-kernel <linux-kernel@vger.kernel.org>, Chen-Yu Tsai <wens@csie.org>, linux-clk <linux-clk@vger.kernel.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org> Subject: Re: [RFC PATCH] clk: sunxi-ng: sun4i: Use CLK_SET_RATE_PARENT for mmc2 clock Date: Mon, 11 Feb 2019 14:35:52 +0000 [thread overview] Message-ID: <20190211143552.2uqx6yy53dyv5lbl@plaes.org> (raw) In-Reply-To: <20190206155227.wbkzvsdgykir4wn5@flea> On Wed, Feb 06, 2019 at 04:52:27PM +0100, Maxime Ripard wrote: > Hi, > > On Wed, Feb 06, 2019 at 10:03:09AM +0000, Priit Laes wrote: > > > > I'm concerned for other users of the PLL-PERIPH clock. AFAIK > > > > all of them, except the HRTIMER, expect the clock rate to stay > > > > the same and not change underneath them. And SATA expects it to > > > > be at 600 MHz, as the datasheet says. And while it may not directly > > > > apply to the LIME2, eMMC on newer SoCs / boards run at the slightly > > > > reduced rate of 50 MHz just fine. > > > > > > > > In the commit in question, clocks without CLK_SET_RATE_PARENT > > > > should be using the old code (now in the if conditional block), > > > > i.e. the behavior should not have changed. > > > > > > > > I don't think this actually "fixes" whatever bug was introduced, > > > > but only papers over the issue, and possible introduces further > > > > issues for other users. > > > > > > You're right, I've overlooked that it was pll-periph being > > > affected. I've dropped it for now. > > > > Any ideas what could be done. I currently have no time to debug it, > > but it affects existing systems. > > I can't find what would change with that commit either if the flag > isn't set, so looking at the register state before and after that > commit would help I guess? Register dump without the patch: $ busybox devmem 0x01c20090 0x0250030E pll-ddr-base 2 2 0 768000000 0 0 50000 pll-ddr-other 1 1 0 768000000 0 0 50000 mmc2 3 3 0 51200000 0 0 50000 Register dump with patch applied, booted from mmc0 and after mounting emmc: $ busybox devmem 0x01c20090 0x8140020B pll-periph-base 3 3 0 1200000000 0 0 50000 pll-periph 6 6 0 600000000 0 0 50000 mmc2 3 3 0 50000000 0 0 50000 > > Maxime > > -- > Maxime Ripard, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-02-11 14:36 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-02-02 15:52 [RFC PATCH] clk: sunxi-ng: sun4i: Use CLK_SET_RATE_PARENT for mmc2 clock Priit Laes 2019-02-02 15:52 ` Priit Laes 2019-02-05 9:45 ` Maxime Ripard 2019-02-05 9:45 ` Maxime Ripard 2019-02-05 13:44 ` Chen-Yu Tsai 2019-02-05 13:44 ` Chen-Yu Tsai 2019-02-06 9:20 ` Maxime Ripard 2019-02-06 9:20 ` Maxime Ripard 2019-02-06 10:03 ` Priit Laes 2019-02-06 10:03 ` Priit Laes 2019-02-06 15:52 ` Maxime Ripard 2019-02-06 15:52 ` Maxime Ripard 2019-02-11 14:35 ` Priit Laes [this message] 2019-02-11 14:35 ` Priit Laes 2019-02-11 15:34 ` Maxime Ripard 2019-02-11 15:34 ` Maxime Ripard 2019-02-12 9:45 ` Priit Laes 2019-02-12 9:45 ` Priit Laes
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