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Message-ID: <53BD9FA3.1040204@gmail.com>
Date: Wed, 09 Jul 2014 22:01:39 +0200
From: Tomasz Figa <tomasz.figa@...il.com>
To: Tomeu Vizoso <tomeu.vizoso@...labora.com>,
Stephen Warren <swarren@...dotorg.org>,
Thierry Reding <thierry.reding@...il.com>,
Mike Turquette <mturquette@...aro.org>, rabin@....in,
linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
CC: Rabin Vincent <rabin.vincent@...ricsson.com>,
Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Subject: Re: [RFC v2 4/5] clk: per-user clock accounting for debug
Hi Tomeu, Rabin,
Please see my comments inline.
On 03.07.2014 16:38, Tomeu Vizoso wrote:
> From: Rabin Vincent <rabin.vincent@...ricsson.com>
>
> When a clock has multiple users, the WARNING on imbalance of
> enable/disable may not show the guilty party since although they may
> have commited the error earlier, the warning is emitted later when some
> other user, presumably innocent, disables the clock.
[snip]
> diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
> index 5f2aba9..d6a5e59 100644
> --- a/drivers/clk/clk-devres.c
> +++ b/drivers/clk/clk-devres.c
> @@ -37,7 +37,8 @@ EXPORT_SYMBOL(devm_clk_provider_get);
>
> struct clk *devm_clk_get(struct device *dev, const char *id)
> {
> - return clk_core_to_clk(devm_clk_provider_get(dev, id));
> + const char *dev_id = dev ? dev_name(dev) : NULL;
> + return clk_core_to_clk(devm_clk_provider_get(dev, id), dev_id, id);
Hmm, correct me if I'm missing something but you're just calling
devm_clk_provider() which guarantees calling of clk_provider_put() on
device removal, but what about the consumer struct being created here?
Shouldn't you rather call normal clk_provider_get() here, then create a
consumer struct for it and then wrap it up using devres, providing
appropriate release function?
> }
> EXPORT_SYMBOL(devm_clk_get);
>
> diff --git a/drivers/clk/clk-highbank.c b/drivers/clk/clk-highbank.c
> index cc1bae1..4e38856 100644
> --- a/drivers/clk/clk-highbank.c
> +++ b/drivers/clk/clk-highbank.c
> @@ -331,7 +331,7 @@ CLK_OF_DECLARE(hb_a9periph, "calxeda,hb-a9periph-clock", hb_a9periph_init);
> static void __init hb_a9bus_init(struct device_node *node)
> {
> struct clk_core *clk = hb_clk_init(node, &a9bclk_ops);
> - clk_prepare_enable(clk_core_to_clk(clk));
> + clk_prepare_enable(clk_core_to_clk(clk, node->full_name, NULL));
> }
> CLK_OF_DECLARE(hb_a9bus, "calxeda,hb-a9bus-clock", hb_a9bus_init);
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 644a824..b887c69 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -568,6 +568,28 @@ static int clk_disable_unused(void)
> }
> late_initcall_sync(clk_disable_unused);
>
> +struct clk *clk_core_to_clk(struct clk_core *clk_core, const char *dev,
> + const char *con)
Name of this function suggests that this is just a simple conversion,
while it creates new object. I would suggest calling this
clk_create_consumer() or something along these lines.
> +{
> + struct clk *clk;
> +
> + clk = kzalloc(sizeof(*clk), GFP_KERNEL);
> + if (!clk)
> + return ERR_PTR(-ENOMEM);
[snip]
> +static void clk_free_clk(struct clk *clk)
> +{
> + kfree(clk);
> +}
Any need for this one-liner? Seems to be used just once below.
> +
> void clk_put(struct clk *clk)
> {
> - __clk_put(clk_to_clk_core(clk));
> + clk_core_t *core = clk_to_clk_core(clk);
> +
> + clk_free_clk(clk);
> + __clk_put(core);
> }
> EXPORT_SYMBOL(clk_put);
>
> diff --git a/drivers/clk/qcom/mmcc-msm8960.c b/drivers/clk/qcom/mmcc-msm8960.c
> index 28a5d30..47f21ea 100644
> --- a/drivers/clk/qcom/mmcc-msm8960.c
> +++ b/drivers/clk/qcom/mmcc-msm8960.c
> @@ -470,7 +470,8 @@ static int pix_rdi_set_parent(struct clk_hw *hw, u8 index)
> * needs to be on at what time.
> */
> for (i = 0; i < num_parents; i++) {
> - ret = clk_prepare_enable(clk_core_to_clk(clk_get_parent_by_index(clk, i)));
> + struct clk_core *parent = clk_get_parent_by_index(clk, i);
> + ret = clk_prepare_enable(clk_core_to_clk(parent, NULL, __clk_get_name(parent)));
Shouldn't this use clk_provider_*() instead? IMHO clk_core_to_clk() and
clk_to_clk_core() shouldn't be available to clock drivers, just the core
clock code. Consumers should operate on struct clks alone, clock drivers
should operate only on struct clk_cores and only the core code should be
responsible for necessary conversions.
> if (ret)
> goto err;
> }
> @@ -498,8 +499,10 @@ static int pix_rdi_set_parent(struct clk_hw *hw, u8 index)
> udelay(1);
>
> err:
> - for (i--; i >= 0; i--)
> - clk_disable_unprepare(clk_core_to_clk(clk_get_parent_by_index(clk, i)));
> + for (i--; i >= 0; i--) {
> + struct clk_core *parent = clk_get_parent_by_index(clk, i);
> + clk_disable_unprepare(clk_core_to_clk(parent, NULL, __clk_get_name(parent)));
Hmm. Memory leak? Every time this operation is called you create a
consumer struct for each parent two times.
> + }
>
> return ret;
> }
> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
> index 5de44c1..550a691 100644
> --- a/drivers/clk/sunxi/clk-sunxi.c
> +++ b/drivers/clk/sunxi/clk-sunxi.c
> @@ -1196,7 +1196,7 @@ static void __init sunxi_init_clocks(const char *clocks[], int nclocks)
> struct clk_core *clk = clk_provider_get(NULL, clocks[i]);
>
> if (!IS_ERR(clk))
> - clk_prepare_enable(clk_core_to_clk(clk));
> + clk_prepare_enable(clk_core_to_clk(clk, NULL, clocks[i]));
Probably should use clk_provider_*()?
> }
> }
>
> diff --git a/drivers/clk/tegra/clk.c b/drivers/clk/tegra/clk.c
> index 385d101..2a03d47 100644
> --- a/drivers/clk/tegra/clk.c
> +++ b/drivers/clk/tegra/clk.c
> @@ -228,7 +228,7 @@ void __init tegra_init_from_table(struct tegra_clk_init_table *tbl,
> }
>
> if (tbl->state)
> - if (clk_prepare_enable(clk_core_to_clk(clk))) {
> + if (clk_prepare_enable(clk_core_to_clk(clk, NULL, __clk_get_name(clk)))) {
Ditto. And all similar cases below which I skipped due to lack of any
added value to this review.
> pr_err("%s: Failed to enable %s\n", __func__,
> __clk_get_name(clk));
> WARN_ON(1);
[snip]
> diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
> index 2c1ece9..9657fc8 100644
> --- a/include/linux/clk-private.h
> +++ b/include/linux/clk-private.h
> @@ -57,6 +57,10 @@ struct clk_core {
>
> struct clk {
> struct clk_core *core;
> + unsigned int enable_count;
> + const char *dev_id;
> + const char *con_id;
> + void *last_disable;
Probably the same as for enables should be done for prepares.
> };
>
> /*
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 87de32c..abfc31a 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -533,7 +533,8 @@ struct clk_core *clk_provider_get_sys(const char *dev_id, const char *con_id);
> struct clk_core *clk_provider_get(struct device *dev, const char *con_id);
> struct clk_core *devm_clk_provider_get(struct device *dev, const char *id);
>
> -#define clk_core_to_clk(core) ((struct clk *)(core))
Btw. this should have been a static inline.
Best regards,
Tomasz
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