Messages in this thread Patch in this message | | | From | Cristian Marussi <> | Subject | [PATCH 1/5] clk: scmi: Allocate CLK operations dynamically | Date | Tue, 27 Feb 2024 19:48:08 +0000 |
| |
SCMI Clocks descriptors expose an increasing number of properties, thing which, in turn, leads to a varying set of supported CLK operations to be associated with each clock.
Providing statically pre-defined CLK operations structs for all the possible combinations of allowed clock features is becoming cumbersome and error-prone.
Allocate the per-clock operations descriptors dynamically and populate it with the strictly needed set of operations depending on the advertised clock properties: one descriptor is created for each distinct combination of clock operations, so minimizing the number of clk_ops structures to the strictly minimum needed.
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> --- drivers/clk/clk-scmi.c | 163 ++++++++++++++++++++++++++++------------- 1 file changed, 114 insertions(+), 49 deletions(-)
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 @@ -2,7 +2,7 @@ /* * System Control and Power Interface (SCMI) Protocol based clock driver * - * Copyright (C) 2018-2022 ARM Ltd. + * Copyright (C) 2018-2024 ARM Ltd. */ #include <linux/clk-provider.h> @@ -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]; static const struct scmi_clk_proto_ops *scmi_proto_clk_ops; struct scmi_clk { @@ -158,42 +166,6 @@ static int scmi_clk_atomic_is_enabled(struct clk_hw *hw) return !!enabled; } -/* - * We can provide enable/disable/is_enabled 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, - .prepare = scmi_clk_enable, - .unprepare = scmi_clk_disable, - .set_parent = scmi_clk_set_parent, - .get_parent = scmi_clk_get_parent, - .determine_rate = scmi_clk_determine_rate, -}; - -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, - .enable = scmi_clk_atomic_enable, - .disable = scmi_clk_atomic_disable, - .is_enabled = scmi_clk_atomic_is_enabled, - .set_parent = scmi_clk_set_parent, - .get_parent = scmi_clk_get_parent, - .determine_rate = scmi_clk_determine_rate, -}; - static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk, const struct clk_ops *scmi_ops) { @@ -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. + * + * 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, + * or NULL on allocation failure. + */ +static const struct clk_ops * +scmi_clk_ops_alloc(struct device *dev, unsigned long feats_key) +{ + struct clk_ops *ops; + + ops = devm_kzalloc(dev, sizeof(*ops), GFP_KERNEL); + if (!ops) + return NULL; + /* + * We can provide enable/disable/is_enabled 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. + */ + if (feats_key & BIT(SCMI_CLK_ATOMIC_SUPPORTED)) { + ops->enable = scmi_clk_atomic_enable; + ops->disable = scmi_clk_atomic_disable; + ops->is_enabled = scmi_clk_atomic_is_enabled; + } else { + ops->prepare = scmi_clk_enable; + ops->unprepare = scmi_clk_disable; + } + + /* Rate ops */ + ops->recalc_rate = scmi_clk_recalc_rate; + ops->round_rate = scmi_clk_round_rate; + ops->determine_rate = scmi_clk_determine_rate; + ops->set_rate = scmi_clk_set_rate; + + /* Parent ops */ + ops->get_parent = scmi_clk_get_parent; + ops->set_parent = scmi_clk_set_parent; + + return ops; +} + +/** + * 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 + * + * 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 + * 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); + + /* 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; + + /* 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, + atomic_threshold); + if (!scmi_ops) + return -ENOMEM; /* Initialize clock parent data. */ if (sclk->info->num_parents > 0) { @@ -318,8 +384,7 @@ static int scmi_clocks_probe(struct scmi_device *sdev) } else { dev_dbg(dev, "Registered clock:%s%s\n", sclk->info->name, - scmi_ops == &scmi_atomic_clk_ops ? - " (atomic ops)" : ""); + scmi_ops->enable ? " (atomic ops)" : ""); hws[idx] = &sclk->hw; } } -- 2.43.0
| |