From mboxrd@z Thu Jan 1 00:00:00 1970 From: kernel@martin.sperl.org (kernel at martin.sperl.org) Date: Fri, 29 Apr 2016 17:42:35 +0000 Subject: [PATCH V4 1/2] clk: bcm2835: mark enabled clocks with CLK_IS_CRITICAL In-Reply-To: <1461951756-16804-1-git-send-email-kernel@martin.sperl.org> References: <1461951756-16804-1-git-send-email-kernel@martin.sperl.org> Message-ID: <1461951756-16804-2-git-send-email-kernel@martin.sperl.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Martin Sperl The bcm2835 firmware enables several clocks and plls before booting the linux kernel. These plls should never get disabled as it may result in a stopped system clock and more. So during probing we check if the clock is enabled and if it is then mark that clock with CLK_IS_CRITICAL. As a consequence this will also enable the corresponding parent plls and pll-divs. This is intended as a stop-gap until CLK_ENABLE_HAND_OFF becomes available, at which point it should be used instead. Signed-off-by: Martin Sperl --- drivers/clk/bcm/clk-bcm2835.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c index 35f8de7..03b7f01 100644 --- a/drivers/clk/bcm/clk-bcm2835.c +++ b/drivers/clk/bcm/clk-bcm2835.c @@ -1251,6 +1251,14 @@ static struct clk *bcm2835_register_clock(struct bcm2835_cprman *cprman, init.flags |= CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE; } + /* if the clock is running, then enable CRITICAL */ + if (cprman_read(cprman, data->ctl_reg) & CM_ENABLE) { + dev_dbg(cprman->dev, + "found firmware enabled clock %s - enabling critical\n", + data->name); + init.flags |= CLK_IS_CRITICAL; + } + clock = devm_kzalloc(cprman->dev, sizeof(*clock), GFP_KERNEL); if (!clock) return NULL; -- 2.1.4