Messages in this thread Patch in this message | | | Subject | Re: [PATCH v2 1/5] clk: scmi: Allocate CLK operations dynamically | From | Stephen Boyd <> | Date | Sun, 07 Apr 2024 21:38:46 -0700 |
| |
Quoting Cristian Marussi (2024-03-25 14:00:21) > diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c > index 8cbe24789c24..d5d369b052bd 100644 > --- a/drivers/clk/clk-scmi.c > +++ b/drivers/clk/clk-scmi.c > @@ -16,6 +16,14 @@ > #define NOT_ATOMIC false > #define ATOMIC true > > +enum scmi_clk_feats { > + SCMI_CLK_ATOMIC_SUPPORTED, > + SCMI_CLK_MAX_FEATS > +}; > + > +#define SCMI_MAX_CLK_OPS (1 << SCMI_CLK_MAX_FEATS) > + > +static const struct clk_ops *clk_ops_db[SCMI_MAX_CLK_OPS];
Can it be 'scmi_clk_ops_db' for some name spacing?
> static const struct scmi_clk_proto_ops *scmi_proto_clk_ops; > > struct scmi_clk { > @@ -230,6 +202,106 @@ static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk, > return ret; > } > > +/** > + * scmi_clk_ops_alloc() - Alloc and configure clock operations > + * @dev: A device reference for devres > + * @feats_key: A bitmap representing the desired clk_ops capabilities.
Drop the period please because it's not consistent with the previous argument descriptor.
> + * > + * Allocate and configure a proper set of clock operations depending on the > + * specifically required SCMI clock features. > + * > + * Return: A pointer to the allocated and configured clk_ops on Success,
Lowercase 'Success'.
> + > +/** > + * scmi_clk_ops_select() - Select a proper set of clock operations > + * @sclk: A reference to an SCMI clock descriptor > + * @atomic_capable: A flag to indicate if atomic mode is supported by the > + * transport > + * @atomic_threshold: Platform atomic threshold value
Is this in nanoseconds, microseconds, or ??? Maybe a better description is "clk_ops are atomic when clk enable_latency is less than X [time unit]"
> + * > + * After having built a bitmap descriptor to represent the set of features > + * needed by this SCMI clock, at first use it to lookup into the set of > + * previously allocated clk_ops to check if a suitable combination of clock > + * operations was already created; when no match is found allocate a brand new > + * set of clk_ops satisfying the required combination of features and save it > + * for future references. > + * > + * In this way only one set of clk_ops is ever created for each different > + * combination that is effectively needed. > + * > + * Return: A pointer to the allocated and configured clk_ops on Success, or
Lowercase 'Success'.
> + * NULL otherwise. > + */ > +static const struct clk_ops * > +scmi_clk_ops_select(struct scmi_clk *sclk, bool atomic_capable, > + unsigned int atomic_threshold) > +{ > + const struct scmi_clock_info *ci = sclk->info; > + unsigned int feats_key = 0; > + const struct clk_ops *ops; > + > + /* > + * Note that when transport is atomic but SCMI protocol did not > + * specify (or support) an enable_latency associated with a > + * clock, we default to use atomic operations mode. > + */ > + if (atomic_capable && ci->enable_latency <= atomic_threshold) > + feats_key |= BIT(SCMI_CLK_ATOMIC_SUPPORTED); > +
Can we have a static_assert() here that makes sure 'feats_key' isn't larger than the size of clk_ops_db?
static_assert(ARRAY_SIZE(clk_ops_db) >= feats_key);
> + /* Lookup previously allocated ops */ > + ops = clk_ops_db[feats_key]; > + if (!ops) { > + ops = scmi_clk_ops_alloc(sclk->dev, feats_key); > + if (!ops) > + return NULL;
This could be less nested if the first lookup is put in scmi_clk_ops_alloc() and the store below is folded in. Or an early return if found.
ops = clk_ops_db[feats_key]; if (ops) return ops;
/* Didn't find one */ ops = scmi_clk_ops_alloc(...) if (!ops) return NULL;
clk_ops_db[feats_key] = ops; return ops; > + > + /* Store new ops combinations */ > + clk_ops_db[feats_key] = ops; > + } > + > + return ops; > +} > + > static int scmi_clocks_probe(struct scmi_device *sdev) > { > int idx, count, err; > @@ -285,16 +357,10 @@ static int scmi_clocks_probe(struct scmi_device *sdev) > sclk->ph = ph; > sclk->dev = dev; > > - /* > - * Note that when transport is atomic but SCMI protocol did not > - * specify (or support) an enable_latency associated with a > - * clock, we default to use atomic operations mode. > - */ > - if (is_atomic && > - sclk->info->enable_latency <= atomic_threshold) > - scmi_ops = &scmi_atomic_clk_ops; > - else > - scmi_ops = &scmi_clk_ops; > + scmi_ops = scmi_clk_ops_select(sclk, is_atomic,
'is_atomic' should probably be 'transport_is_atomic' so this reads easier.
> + atomic_threshold); > + if (!scmi_ops) > + return -ENOMEM; > > /* Initialize clock parent data. */ > if (sclk->info->num_parents > 0) {
| |