On Wed, 2019-01-16 at 08:37 -0800, Stephen Boyd wrote:
Quoting Lubomir Rintel (2019-01-16 01:35:05)
There could be vital functionality running on the SP PJ1 core it can not be restarted just by turning the clock back on.
On the OLPC laptop, the keyboard controller code runs there. It wouldn't be possible to load the driver for it as a module if the clock is disabled on boot.
Cc: stable@vger.kernel.org # v4.18+ Fixes: commit fc27c2394d96 ("clk: mmp2: add SP clock") Signed-off-by: Lubomir Rintel lkundrak@v3.sk
drivers/clk/mmp/clk-of-mmp2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/mmp/clk-of-mmp2.c b/drivers/clk/mmp/clk-of-mmp2.c index f2a1c9bbaa63..3e33f1295f59 100644 --- a/drivers/clk/mmp/clk-of-mmp2.c +++ b/drivers/clk/mmp/clk-of-mmp2.c @@ -246,7 +246,7 @@ static struct mmp_param_gate_clk apmu_gate_clks[] = { {MMP2_CLK_CCIC1, "ccic1_clk", "ccic1_mix_clk", CLK_SET_RATE_PARENT, APMU_CCIC1, 0x1b, 0x1b, 0x0, 0, &ccic1_lock}, {MMP2_CLK_CCIC1_PHY, "ccic1_phy_clk", "ccic1_mix_clk", CLK_SET_RATE_PARENT, APMU_CCIC1, 0x24, 0x24, 0x0, 0, &ccic1_lock}, {MMP2_CLK_CCIC1_SPHY, "ccic1_sphy_clk", "ccic1_sphy_div", CLK_SET_RATE_PARENT, APMU_CCIC1, 0x300, 0x300, 0x0, 0, &ccic1_lock},
{MMP2_CLK_SP, "sp_clk", NULL, CLK_SET_RATE_PARENT, APMU_SP, 0x1b, 0x1b, 0x0, 0, &sp_lock},
{MMP2_CLK_SP, "sp_clk", NULL, CLK_SET_RATE_PARENT | CLK_IGNORE_UNUSED, APMU_SP, 0x1b, 0x1b, 0x0, 0, &sp_lock},Is it a critical clk that should never be turned off?
I don't think it is. It is entirely plausible to have no use for the "security processor", and in that case it's just okay to keep the clock disabled.
If so, mark it as CLK_IS_CRITICAL. Either way, please add a comment in the code about why CLK_IGNORE_UNUSED or CLK_IS_CRITICAL is used.
Okay.
Thanks, Lubo