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Date: Wed, 21 Jan 2015 18:23:19 -0800
From: Stephen Boyd <sboyd@...eaurora.org>
To: Tomeu Vizoso <tomeu.vizoso@...labora.com>
Cc: linux-kernel@...r.kernel.org,
Mike Turquette <mturquette@...aro.org>,
Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Subject: Re: [PATCH v11 4/4] clk: Add module for unit tests
On 01/21, Tomeu Vizoso wrote:
> diff --git a/drivers/clk/Kconfig.debug b/drivers/clk/Kconfig.debug
> new file mode 100644
> index 0000000..840b790
> --- /dev/null
> +++ b/drivers/clk/Kconfig.debug
> @@ -0,0 +1,6 @@
> +config COMMON_CLK_TEST
> + tristate "Unit tests for the Common Clock Framework"
depends on DEBUG_KERNEL?
> + default n
Drop this line. n is the default.
> + ---help---
> + This driver runs several tests on the Common Clock Framework.
s/driver/module/ ?
> diff --git a/drivers/clk/clk-test.c b/drivers/clk/clk-test.c
> new file mode 100644
> index 0000000..4eb7eb4
> --- /dev/null
> +++ b/drivers/clk/clk-test.c
> @@ -0,0 +1,325 @@
> +/*
> + * Copyright (C) 2015 Google, Inc
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * Unit tests for the Common Clock Framework
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/printk.h>
> +#include <linux/slab.h>
#include <linux/clk.h> ?
> +
> +/* Assumed to be sorted */
> +static const unsigned long allowed_rates[] = { 0, 100, 200, 300, 400, 500 };
> +
> +struct test_clk {
> + struct clk_hw hw;
> + unsigned long rate;
> +};
> +
> +static inline struct test_clk *to_test_clk(struct clk_hw *hw)
> +{
> + return container_of(hw, struct test_clk, hw);
> +}
> +
> +static long test_clk_determine_rate(struct clk_hw *hw,
> + unsigned long rate,
> + unsigned long min_rate,
> + unsigned long max_rate,
> + unsigned long *best_parent_rate,
> + struct clk_hw **best_parent)
> +{
> + struct clk *parent;
> + unsigned long target_rate = 0;
> + unsigned int i;
> +
> + for (i = 0; i < ARRAY_SIZE(allowed_rates); i++) {
> +
> + if (allowed_rates[i] > max_rate) {
> + if (i > 0)
> + target_rate = allowed_rates[i - 1];
> + else
> + target_rate = 0;
> + break;
> + }
> +
> + if (allowed_rates[i] < min_rate)
> + continue;
> +
> + if (allowed_rates[i] >= rate) {
> + target_rate = allowed_rates[i];
> + break;
> + }
> + }
> +
> + parent = clk_get_parent(hw->clk);
> + if (parent) {
> + *best_parent = __clk_get_hw(parent);
> + *best_parent_rate = __clk_determine_rate(__clk_get_hw(parent),
> + target_rate / 2,
> + min_rate,
> + max_rate);
So child's a multiplier? That's new.
> + }
> +
> + return target_rate;
> +}
> +
> +static unsigned long test_clk_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct test_clk *test_clk = to_test_clk(hw);
> +
> + return test_clk->rate;
It would be good to actually use parent_rate here to match
whatever is done in determine_rate().
> +}
> +
> +static int test_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct test_clk *test_clk = to_test_clk(hw);
> +
> + test_clk->rate = rate;
> +
> + return 0;
> +}
> +
> +static const struct clk_ops test_clk_ops = {
> + .determine_rate = test_clk_determine_rate,
> + .recalc_rate = test_clk_recalc_rate,
> + .set_rate = test_clk_set_rate,
> +};
> +
> +static struct clk *init_test_clk(const char *name, const char *parent_name)
> +{
> + struct test_clk *test_clk;
> + struct clk *clk;
> + struct clk_init_data init;
> + int err;
> +
> + test_clk = kzalloc(sizeof(*test_clk), GFP_KERNEL);
> + if (!test_clk)
> + return ERR_PTR(-ENOMEM);
> +
> + test_clk->rate = 0;
It would probably be good to assign some initial rate besides 0.
> +
> + init.name = name;
> + init.ops = &test_clk_ops;
> +
> + if (parent_name) {
> + init.parent_names = &parent_name;
> + init.num_parents = 1;
> + init.flags = CLK_SET_RATE_PARENT;
> + } else {
> + init.parent_names = NULL;
> + init.num_parents = 0;
> + init.flags = CLK_IS_ROOT;
> + }
> +
> + test_clk->hw.init = &init;
> +
> + clk = clk_register(NULL, &test_clk->hw);
> + if (IS_ERR(clk)) {
> + printk("%s: error registering clk: %ld\n", __func__,
> + PTR_ERR(clk));
Use pr_error() throughout? And use a pr_fmt with __func__ to make
things simpler.
> + return clk;
> + }
> +
> + err = clk_register_clkdev(clk, name, NULL);
> + if (err)
> + printk("%s: error registering alias: %d\n", __func__, err);
> +
> + return clk;
> +}
> +
> +static void test_ceiling(struct clk *clk)
> +{
> + unsigned long rate;
> + int ret;
> +
> + ret = clk_set_max_rate(clk, 399);
> + if (ret)
> + printk("%s: error setting ceiling: %d\n", __func__, ret);
> +
> + rate = clk_round_rate(clk, 400);
> + if (rate != 300)
> + printk("%s: unexpected rounded rate: %lu != 300\n", __func__, rate);
> +
> + ret = clk_set_rate(clk, 400);
> + if (ret)
> + printk("%s: error setting rate: %d\n", __func__, ret);
> +
> + rate = clk_get_rate(clk);
> + if (rate != 300)
Perhaps these tests for constraints should just be checking to
make sure we don't go outside the range we want. Something more
like:
if (rate > 399)
> + printk("%s: unexpected rate: %lu != 300\n", __func__, rate);
> +
> + ret = clk_set_max_rate(clk, ULONG_MAX);
> + if (ret)
> + printk("%s: error setting ceiling: %d\n", __func__, ret);
> +}
> +
> +static void test_floor(struct clk *clk)
> +{
> + unsigned long rate;
> + int ret;
> +
> + ret = clk_set_min_rate(clk, 199);
> + if (ret)
> + printk("%s: error setting floor: %d\n", __func__, ret);
> +
> + rate = clk_round_rate(clk, 90);
> + if (rate != 200)
> + printk("%s: unexpected rounded rate: %lu != 200\n", __func__, rate);
> +
> + ret = clk_set_rate(clk, 90);
> + if (ret)
> + printk("%s: error setting rate: %d\n", __func__, ret);
> +
> + rate = clk_get_rate(clk);
> + if (rate != 200)
And
if (rate < 200)
This reminds me, it would be good to indicate in the
documentation if min/max is inclusive or exclusive.
> + printk("%s: unexpected rate: %lu != 200\n", __func__, rate);
> +
> + ret = clk_set_min_rate(clk, 0);
> + if (ret)
> + printk("%s: error setting floor: %d\n", __func__, ret);
> +}
> +
> +static void test_unsatisfiable(struct clk *clk)
> +{
> + struct clk *clk2 = clk_get_sys(NULL, "clk");
> + unsigned long rate;
> + int ret;
> +
> + if (IS_ERR(clk2))
> + printk("%s: error getting clk: %ld\n", __func__,
> + PTR_ERR(clk2));
> +
> + ret = clk_set_min_rate(clk, 99);
> + if (ret)
> + printk("%s: error setting floor: %d\n", __func__, ret);
> +
> + ret = clk_set_max_rate(clk, 199);
> + if (ret)
> + printk("%s: error setting ceiling: %d\n", __func__, ret);
> +
> + ret = clk_set_min_rate(clk2, 399);
> + if (ret)
> + printk("%s: error setting floor: %d\n", __func__, ret);
Shouldn't this one fail and print an error?
> +
> + ret = clk_set_max_rate(clk2, 499);
> + if (ret)
> + printk("%s: error setting ceiling: %d\n", __func__, ret);
This one should be ok though.
> +
> + ret = clk_set_rate(clk, 90);
> + if (ret)
> + printk("%s: error setting rate: %d\n", __func__, ret);
> +
> + /*
> + * It's expected that the rate is the highest rate that is still
> + * below the smallest ceiling
> + */
> + rate = clk_get_rate(clk);
> + if (rate != 100)
> + printk("%s: unexpected rate: %lu != 100\n", __func__, rate);
> +
> + clk_put(clk2);
> +
> + ret = clk_set_min_rate(clk, 0);
> + if (ret)
> + printk("%s: error setting floor: %d\n", __func__, ret);
> +
> + ret = clk_set_max_rate(clk, ULONG_MAX);
> + if (ret)
> + printk("%s: error setting ceiling: %d\n", __func__, ret);
> +}
> +
> +static void test_constrained_parent(struct clk *clk, struct clk *parent)
> +{
> + unsigned long rate;
> + int ret;
> +
> + ret = clk_set_max_rate(parent, 199);
> + if (ret)
> + printk("%s: error setting ceiling: %d\n", __func__, ret);
> +
> + ret = clk_set_rate(clk, 200);
> + if (ret)
> + printk("%s: error setting rate: %d\n", __func__, ret);
> +
> + rate = clk_get_rate(clk);
> + if (rate != 200)
> + printk("%s: unexpected rate: %lu != 200\n", __func__, rate);
> +
> + rate = clk_get_rate(parent);
> + if (rate != 100)
> + printk("%s: unexpected parent rate: %lu != 100\n", __func__, rate);
> +
> + ret = clk_set_max_rate(parent, ULONG_MAX);
> + if (ret)
> + printk("%s: error setting ceiling: %d\n", __func__, ret);
> +}
> +
> +static void test_constraint_with_parent(struct clk *clk, struct clk *parent)
> +{
> + unsigned long rate;
> + int ret;
> +
> + ret = clk_set_min_rate(clk, 201);
> + if (ret)
> + printk("%s: error setting ceiling: %d\n", __func__, ret);
> +
> + ret = clk_set_rate(clk, 300);
> + if (ret)
> + printk("%s: error setting rate: %d\n", __func__, ret);
> +
> + rate = clk_get_rate(clk);
> + if (rate != 300)
> + printk("%s: unexpected rate: %lu != 300\n", __func__, rate);
> +
> + rate = clk_get_rate(parent);
> + if (rate != 300)
> + printk("%s: unexpected parent rate: %lu != 300\n", __func__, rate);
> +
> + ret = clk_set_max_rate(parent, ULONG_MAX);
> + if (ret)
> + printk("%s: error setting ceiling: %d\n", __func__, ret);
> +}
> +
> +static int __init clk_test_init(void)
> +{
> + struct clk *parent, *clk;
> +
> + printk("---------- Common Clock Framework test results ----------\n");
> +
> + parent = init_test_clk("parent", NULL);
> + if (IS_ERR(parent)) {
> + printk("%s: error registering parent: %ld\n", __func__,
> + PTR_ERR(parent));
> + return PTR_ERR(parent);
> + }
> +
> + clk = init_test_clk("clk", "parent");
> + if (IS_ERR(clk)) {
> + printk("%s: error registering clk: %ld\n", __func__,
> + PTR_ERR(clk));
> + return PTR_ERR(clk);
> + }
> +
> + test_ceiling(clk);
> + test_floor(clk);
> + test_unsatisfiable(clk);
> + test_constrained_parent(clk, parent);
> + test_constraint_with_parent(clk, parent);
> +
It would be good to unregister the clocks here so that we don't
leave them hanging around unused.
--
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a Linux Foundation Collaborative Project
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