[PATCH 4.2.y-ckt 210/218] clk: versatile: sp810: support reentrance

From: Kamal Mostafa
Date: Thu Mar 31 2016 - 16:23:45 EST

4.2.8-ckt7 -stable review patch. If anyone has any objections, please let me know.


From: Linus Walleij <linus.walleij@xxxxxxxxxx>

commit ec7957a6aa0aaf981fb8356dc47a2cdd01cde03c upstream.

Despite care take to allocate clocks state containers the
SP810 driver actually just supports creating one instance:
all clocks registered for every instance will end up with the
exact same name and __clk_init() will fail.

Rename the timclken<0> .. timclken<n> to sp810_<instance>_<n>
so every clock on every instance gets a unique name.

This is necessary for the RealView PBA8 which has two SP810
blocks: the second block will not register its clocks unless
every clock on every instance is unique and results in boot
logs like this:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at ../drivers/clk/versatile/clk-sp810.c:137
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted
4.5.0-rc2-00030-g352718fc39f6-dirty #225
Hardware name: ARM RealView Machine (Device Tree Support)
[<c00167f8>] (unwind_backtrace) from [<c0013204>]
[<c0013204>] (show_stack) from [<c01a049c>]
[<c01a049c>] (dump_stack) from [<c0024990>]
[<c0024990>] (warn_slowpath_common) from [<c0024a68>]
[<c0024a68>] (warn_slowpath_null) from [<c051eb44>]
[<c051eb44>] (clk_sp810_of_setup) from [<c051e3a4>]
[<c051e3a4>] (of_clk_init) from [<c0504714>]
[<c0504714>] (time_init) from [<c0501b18>]
[<c0501b18>] (start_kernel) from [<7000807c>] (0x7000807c)
---[ end trace cb88537fdc8fa200 ]---

Cc: Michael Turquette <mturquette@xxxxxxxxxxxx>
Cc: Pawel Moll <pawel.moll@xxxxxxx>
Fixes: 6e973d2c4385 "clk: vexpress: Add separate SP810 driver"
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
drivers/clk/versatile/clk-sp810.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/versatile/clk-sp810.c b/drivers/clk/versatile/clk-sp810.c
index b674ffc..72af18b 100644
--- a/drivers/clk/versatile/clk-sp810.c
+++ b/drivers/clk/versatile/clk-sp810.c
@@ -141,6 +141,7 @@ static void __init clk_sp810_of_setup(struct device_node *node)
const char *parent_names[2];
char name[12];
struct clk_init_data init;
+ static int instance;
int i;

if (!sp810) {
@@ -172,7 +173,7 @@ static void __init clk_sp810_of_setup(struct device_node *node)
init.num_parents = ARRAY_SIZE(parent_names);

for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
- snprintf(name, ARRAY_SIZE(name), "timerclken%d", i);
+ snprintf(name, sizeof(name), "sp810_%d_%d", instance, i);

sp810->timerclken[i].sp810 = sp810;
sp810->timerclken[i].channel = i;
@@ -184,5 +185,6 @@ static void __init clk_sp810_of_setup(struct device_node *node)

of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
+ instance++;
CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);