From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <5BEAFE05.9070905@baylibre.com> Date: Tue, 13 Nov 2018 17:38:29 +0100 From: Neil Armstrong MIME-Version: 1.0 To: stable@vger.kernel.org CC: Jerome Brunet , Carlo Caione , Kevin Hilman , Christian Hewitt , Michael Turquette , linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] clk: meson-gxbb: set fclk_div3 as CLK_IS_CRITICAL References: <20181105230820.3562-1-jbrunet@baylibre.com> In-Reply-To: <20181105230820.3562-1-jbrunet@baylibre.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: Hi Stable team, Le 06/11/2018 00:08, Jerome Brunet a �crit : > From: Christian Hewitt > > On the Khadas VIM2 (GXM) and LePotato (GXL) board there are problems > with reboot; e.g. a ~60 second delay between issuing reboot and the > board power cycling (and in some OS configurations reboot will fail > and require manual power cycling). > > Similar to 'commit c987ac6f1f088663b6dad39281071aeb31d450a8 ("clk: > meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL")' the SCPI Cortex-M4 > Co-Processor seems to depend on FCLK_DIV3 being operational. > > Until commit 05f814402d6174369b3b29832cbb5eb5ed287059 ("clk: > meson: add fdiv clock gates"), this clock was modeled and left on by > the bootloader. > > We don't have precise documentation about the SCPI Co-Processor and > its clock requirement so we are learning things the hard way. > > Marking this clock as critical solves the problem but it should not > be viewed as final solution. Ideally, the SCPI driver should claim > these clocks. We also depends on some clock hand-off mechanism > making its way to CCF, to make sure the clock stays on between its > registration and the SCPI driver probe. > > Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates") > Signed-off-by: Christian Hewitt > Signed-off-by: Jerome Brunet Could this patch go into the next 4.18 stable release since it hit linus master with commit id e2576c8bdfd462c34b8a46c0084e7c30b0851bf4 ? Thanks, Neil > --- > drivers/clk/meson/gxbb.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c > index 9309cfaaa464..4ada9668fd49 100644 > --- a/drivers/clk/meson/gxbb.c > +++ b/drivers/clk/meson/gxbb.c > @@ -506,6 +506,18 @@ static struct clk_regmap gxbb_fclk_div3 = { > .ops = &clk_regmap_gate_ops, > .parent_names = (const char *[]){ "fclk_div3_div" }, > .num_parents = 1, > + /* > + * FIXME: > + * This clock, as fdiv2, is used by the SCPI FW and is required > + * by the platform to operate correctly. > + * Until the following condition are met, we need this clock to > + * be marked as critical: > + * a) The SCPI generic driver claims and enable all the clocks > + * it needs > + * b) CCF has a clock hand-off mechanism to make the sure the > + * clock stays on until the proper driver comes along > + */ > + .flags = CLK_IS_CRITICAL, > }, > }; > >