From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: barebox@lists.infradead.org
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: [PATCH v2 08/28] clk: Port clock dependency resolution code
Date: Wed, 9 Nov 2016 08:13:56 -0800 [thread overview]
Message-ID: <1478708056-7875-9-git-send-email-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <1478708056-7875-1-git-send-email-andrew.smirnov@gmail.com>
Port the clock dependency resolution algorithm utilized by Linux
kernel's version of of_clk_init(), to allow for SoCs whose DT clock
configuration reqires such behaviour for correct initialization (Vybrid
is one such example).
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
drivers/clk/clk.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 82 insertions(+), 7 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 630a84d..a38f339 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -404,7 +404,7 @@ EXPORT_SYMBOL_GPL(of_clk_del_provider);
struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
{
struct of_clk_provider *provider;
- struct clk *clk = ERR_PTR(-ENOENT);
+ struct clk *clk = ERR_PTR(-EPROBE_DEFER);
/* Check if we have such a provider in our array */
list_for_each_entry(provider, &of_clk_providers, link) {
@@ -437,6 +437,47 @@ char *of_clk_get_parent_name(struct device_node *np, unsigned int index)
}
EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
+struct clock_provider {
+ of_clk_init_cb_t clk_init_cb;
+ struct device_node *np;
+ struct list_head node;
+};
+
+/*
+ * This function looks for a parent clock. If there is one, then it
+ * checks that the provider for this parent clock was initialized, in
+ * this case the parent clock will be ready.
+ */
+static int parent_ready(struct device_node *np)
+{
+ int i = 0;
+
+ while (true) {
+ struct clk *clk = of_clk_get(np, i);
+
+ /* this parent is ready we can check the next one */
+ if (!IS_ERR(clk)) {
+ clk_put(clk);
+ i++;
+ continue;
+ }
+
+ /* at least one parent is not ready, we exit now */
+ if (PTR_ERR(clk) == -EPROBE_DEFER)
+ return 0;
+
+ /*
+ * Here we make assumption that the device tree is
+ * written correctly. So an error means that there is
+ * no more parent. As we didn't exit yet, then the
+ * previous parent are ready. If there is no clock
+ * parent, no need to wait for them, then we can
+ * consider their absence as being ready
+ */
+ return 1;
+ }
+}
+
/**
* of_clk_init() - Scan and init clock providers from the DT
* @root: parent of the first level to probe or NULL for the root of the tree
@@ -449,8 +490,11 @@ EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
*/
int of_clk_init(struct device_node *root, const struct of_device_id *matches)
{
+ struct clock_provider *clk_provider, *next;
+ bool is_init_done;
+ bool force = false;
+ LIST_HEAD(clk_provider_list);
const struct of_device_id *match;
- int rc;
if (!root)
root = of_find_node_by_path("/");
@@ -459,12 +503,43 @@ int of_clk_init(struct device_node *root, const struct of_device_id *matches)
if (!matches)
matches = __clk_of_table_start;
+ /* First prepare the list of the clocks providers */
for_each_matching_node_and_match(root, matches, &match) {
- of_clk_init_cb_t clk_init_cb = (of_clk_init_cb_t)match->data;
- rc = clk_init_cb(root);
- if (rc)
- pr_err("%s: failed to init clock for %s: %d\n",
- __func__, root->full_name, rc);
+ struct clock_provider *parent;
+
+ if (!of_device_is_available(root))
+ continue;
+
+ parent = xzalloc(sizeof(*parent));
+
+ parent->clk_init_cb = match->data;
+ parent->np = root;
+ list_add_tail(&parent->node, &clk_provider_list);
+ }
+
+ while (!list_empty(&clk_provider_list)) {
+ is_init_done = false;
+ list_for_each_entry_safe(clk_provider, next,
+ &clk_provider_list, node) {
+
+ if (force || parent_ready(clk_provider->np)) {
+
+ clk_provider->clk_init_cb(clk_provider->np);
+
+ list_del(&clk_provider->node);
+ free(clk_provider);
+ is_init_done = true;
+ }
+ }
+
+ /*
+ * We didn't manage to initialize any of the
+ * remaining providers during the last loop, so now we
+ * initialize all the remaining ones unconditionally
+ * in case the clock parent was not mandatory
+ */
+ if (!is_init_done)
+ force = true;
}
return 0;
--
2.5.5
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next prev parent reply other threads:[~2016-11-09 16:15 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-09 16:13 [PATCH v2 00/28] Vybrid support in Barebox Andrey Smirnov
2016-11-09 16:13 ` [PATCH v2 01/28] i.MX: Add primitive functions for VF610 family Andrey Smirnov
2016-11-09 16:13 ` [PATCH v2 02/28] i.MX: Add register definitions for VF610 SoC Andrey Smirnov
2016-11-09 16:13 ` [PATCH v2 03/28] i.MX: Add DEBUG_LL hooks for VF610 Andrey Smirnov
2016-11-09 16:13 ` [PATCH v2 04/28] i.MX: scripts: Add "vf610" soc to imx-image Andrey Smirnov
2016-11-09 16:13 ` [PATCH v2 05/28] i.MX: Add support for VF610 Tower board Andrey Smirnov
2016-11-09 16:13 ` [PATCH v2 06/28] pinctrl: Add provisions to control GPIO pin direction Andrey Smirnov
2016-11-09 16:13 ` [PATCH v2 07/28] i.MX: Add pinctrl driver for VF610 Andrey Smirnov
2016-11-09 16:13 ` Andrey Smirnov [this message]
2016-11-09 16:13 ` [PATCH v2 09/28] clk: Port of_clk_set_defaults() Andrey Smirnov
2016-11-15 7:53 ` Sascha Hauer
2016-11-09 16:13 ` [PATCH v2 10/28] i.MX: Move clk code from 'mach-imx' to 'drivers' Andrey Smirnov
2016-11-09 16:13 ` [PATCH v2 11/28] i.MX: clk: Port imx_clk_gate2_cgr() Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 12/28] i.MX: clk: Add IMX_PLLV3_USB_VF610 support Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 13/28] i.MX: clk: Port imx_check_clocks() Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 14/28] i.MX: clk: Port imx_clk_mux_flags from Linux Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 15/28] i.MX: Add VF610 clock tree initialization code Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 16/28] vf610: Give enet_osc explicit "enet_ext" name Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 17/28] i.MX: Add 'lpuart' serial driver Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 18/28] i.MX: i2c: Use read/write adapter functions Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 19/28] i.MX: i2c: Add Vybrid support Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 20/28] i.MX: esdhc: Do not rely on CPU type for quirks Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 21/28] i.MX: esdhc: Request "per" clock explicitly Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 22/28] i.MX: Kconfig: Enable OCOTP on Vybrid Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 23/28] i.MX: ocotp: Remove unused #define Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 24/28] i.MX: ocotp: Account for shadow memory gaps Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 25/28] i.MX: ocotp: Add Vybrid support Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 26/28] i.MX: fec: Enable all clocks specified for FEC Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 27/28] i.MX: fec: Add support for Vybrid variant Andrey Smirnov
2016-11-09 16:14 ` [PATCH v2 28/28] gpio: Add GPIO driver for Vybrid Andrey Smirnov
2016-11-11 8:21 ` [PATCH v2 00/28] Vybrid support in Barebox Sascha Hauer
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