Messages in this thread | | | From | Vincent Guittot <> | Date | Fri, 10 Dec 2021 11:52:39 +0100 | Subject | Re: [PATCH v7 16/16] clk: scmi: Support atomic clock enable/disable API |
| |
Hi Cristian,
On Mon, 29 Nov 2021 at 20:13, Cristian Marussi <cristian.marussi@arm.com> wrote: > > Support also atomic enable/disable clk_ops beside the bare non-atomic one > (prepare/unprepare) when the underlying SCMI transport is configured to > support atomic transactions for synchronous commands. > > Cc: Michael Turquette <mturquette@baylibre.com> > Cc: Stephen Boyd <sboyd@kernel.org> > Cc: linux-clk@vger.kernel.org > Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> > --- > V5 --> V6 > - add concurrent availability of atomic and non atomic reqs > --- > drivers/clk/clk-scmi.c | 56 +++++++++++++++++++++++++++++++++++------- > 1 file changed, 47 insertions(+), 9 deletions(-) > > diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c > index 1e357d364ca2..50033d873dde 100644 > --- a/drivers/clk/clk-scmi.c > +++ b/drivers/clk/clk-scmi.c > @@ -88,21 +88,53 @@ static void scmi_clk_disable(struct clk_hw *hw) > scmi_proto_clk_ops->disable(clk->ph, clk->id); > } > > +static int scmi_clk_atomic_enable(struct clk_hw *hw) > +{ > + struct scmi_clk *clk = to_scmi_clk(hw); > + > + return scmi_proto_clk_ops->enable_atomic(clk->ph, clk->id); > +} > + > +static void scmi_clk_atomic_disable(struct clk_hw *hw) > +{ > + struct scmi_clk *clk = to_scmi_clk(hw); > + > + scmi_proto_clk_ops->disable_atomic(clk->ph, clk->id); > +} > + > +/* > + * We can provide enable/disable atomic callbacks only if the underlying SCMI > + * transport for an SCMI instance is configured to handle SCMI commands in an > + * atomic manner. > + * > + * When no SCMI atomic transport support is available we instead provide only > + * the prepare/unprepare API, as allowed by the clock framework when atomic > + * calls are not available. > + * > + * Two distinct sets of clk_ops are provided since we could have multiple SCMI > + * instances with different underlying transport quality, so they cannot be > + * shared. > + */ > static const struct clk_ops scmi_clk_ops = { > .recalc_rate = scmi_clk_recalc_rate, > .round_rate = scmi_clk_round_rate, > .set_rate = scmi_clk_set_rate, > - /* > - * We can't provide enable/disable callback as we can't perform the same > - * in atomic context. Since the clock framework provides standard API > - * clk_prepare_enable that helps cases using clk_enable in non-atomic > - * context, it should be fine providing prepare/unprepare. > - */ > .prepare = scmi_clk_enable, > .unprepare = scmi_clk_disable, > }; > > -static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk) > +static const struct clk_ops scmi_atomic_clk_ops = { > + .recalc_rate = scmi_clk_recalc_rate, > + .round_rate = scmi_clk_round_rate, > + .set_rate = scmi_clk_set_rate, > + .prepare = scmi_clk_enable, > + .unprepare = scmi_clk_disable, > + .enable = scmi_clk_atomic_enable,
For each clock, we have to start with clk_prepare and then clk_enable this means that for scmi clk we will do scmi_clk_enable then scmi_clk_atomic_enable
scmi_clk_enable and scmi_clk_atomic_enable ends up doing the same thing: scmi_clock_config_set but the atomic version doesn't sleep
So you will set enable twice the clock.
This is confirmed when testing your series with virtio scmi backend as I can see to consecutive scmi clk set enable request for the same clock
In case of atomic mode, the clk_prepare should be a nop
> + .disable = scmi_clk_atomic_disable, > +}; > + > +static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk, > + const struct clk_ops *scmi_ops) > { > int ret; > unsigned long min_rate, max_rate; > @@ -110,7 +142,7 @@ static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk) > struct clk_init_data init = { > .flags = CLK_GET_RATE_NOCACHE, > .num_parents = 0, > - .ops = &scmi_clk_ops, > + .ops = scmi_ops, > .name = sclk->info->name, > }; > > @@ -145,6 +177,7 @@ static int scmi_clocks_probe(struct scmi_device *sdev) > struct device_node *np = dev->of_node; > const struct scmi_handle *handle = sdev->handle; > struct scmi_protocol_handle *ph; > + const struct clk_ops *scmi_ops; > > if (!handle) > return -ENODEV; > @@ -168,6 +201,11 @@ static int scmi_clocks_probe(struct scmi_device *sdev) > clk_data->num = count; > hws = clk_data->hws; > > + if (handle->is_transport_atomic(handle)) > + scmi_ops = &scmi_atomic_clk_ops; > + else > + scmi_ops = &scmi_clk_ops; > + > for (idx = 0; idx < count; idx++) { > struct scmi_clk *sclk; > > @@ -184,7 +222,7 @@ static int scmi_clocks_probe(struct scmi_device *sdev) > sclk->id = idx; > sclk->ph = ph; > > - err = scmi_clk_ops_init(dev, sclk); > + err = scmi_clk_ops_init(dev, sclk, scmi_ops); > if (err) { > dev_err(dev, "failed to register clock %d\n", idx); > devm_kfree(dev, sclk); > -- > 2.17.1 >
| |