[PATCH v13 6/6] clk: Add module for unit tests

[Tomeu Vizoso]

This module registers a clock hierarchy and performs several operations
against them checking that the result is expected.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
---
 drivers/clk/Kconfig       |   1 +
 drivers/clk/Kconfig.debug |   6 +
 drivers/clk/Makefile      |   1 +
 drivers/clk/clk-test.c    | 326 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 334 insertions(+)
 create mode 100644 drivers/clk/Kconfig.debug
 create mode 100644 drivers/clk/clk-test.c

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 3f44f29..03c500f 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -135,6 +135,7 @@ config COMMON_CLK_PXA
 	  Sypport for the Marvell PXA SoC.
 
 source "drivers/clk/qcom/Kconfig"
+source "drivers/clk/Kconfig.debug"
 
 endmenu
 
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"
+	default n
+	---help---
+	  This driver runs several tests on the Common Clock Framework.
+
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index d5fba5b..4ee1475 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -68,3 +68,4 @@ obj-$(CONFIG_ARCH_U8500)		+= ux500/
 obj-$(CONFIG_COMMON_CLK_VERSATILE)	+= versatile/
 obj-$(CONFIG_X86)			+= x86/
 obj-$(CONFIG_ARCH_ZYNQ)			+= zynq/
+obj-$(CONFIG_COMMON_CLK_TEST)		+= clk-test.o
diff --git a/drivers/clk/clk-test.c b/drivers/clk/clk-test.c
new file mode 100644
index 0000000..e1032f2a
--- /dev/null
+++ b/drivers/clk/clk-test.c
@@ -0,0 +1,326 @@
+/*
+ * 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/module.h>
+#include <linux/printk.h>
+#include <linux/slab.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);
+	}
+
+	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;
+}
+
+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;
+
+	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));
+		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)
+		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)
+		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);
+
+	ret = clk_set_max_rate(clk2, 499);
+	if (ret)
+		printk("%s: error setting ceiling: %d\n", __func__, ret);
+
+	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);
+
+	printk("---------------------------------------------------------\n");
+
+	return 0;
+}
+
+module_init(clk_test_init);
+
+MODULE_LICENSE("GPL");
-- 
1.9.3

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