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oxnas: clk-oxnas: rework pllb enable function

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kernel lock debugging unveiled that we should not call
of_reset_control_get inside a clock's enable operation (see below)

move of_reset_control_* previously used in pllb_clk_enable to new
pllb_clk_prepare and pllb_clk_unprepare functions.
use a container to carry runtime information.

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2742 lockdep_trace_alloc+0xb8/0xfc()
DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.26 #6
[<c001a6ac>] (unwind_backtrace) from [<c0016dec>] (show_stack+0x10/0x14)
[<c0016dec>] (show_stack) from [<c0194f68>] (dump_stack+0x7c/0x94)
[<c0194f68>] (dump_stack) from [<c0021b50>] (warn_slowpath_common+0x68/0x8c)
[<c0021b50>] (warn_slowpath_common) from [<c0021ba4>] (warn_slowpath_fmt+0x30/0x40)
[<c0021ba4>] (warn_slowpath_fmt) from [<c0061b30>] (lockdep_trace_alloc+0xb8/0xfc)
[<c0061b30>] (lockdep_trace_alloc) from [<c00cb740>] (kmem_cache_alloc+0x1c/0xf8)
[<c00cb740>] (kmem_cache_alloc) from [<c01d33c8>] (of_reset_control_get+0xe8/0x12c)
[<c01d33c8>] (of_reset_control_get) from [<c0269228>] (pllb_clk_enable+0x14/0xbc)
[<c0269228>] (pllb_clk_enable) from [<c0265738>] (__clk_enable+0x54/0xa0)
[<c0265738>] (__clk_enable) from [<c0265acc>] (clk_enable+0x18/0x2c)
[<c0265acc>] (clk_enable) from [<c04325f8>] (oxnas_pcie_probe+0x3b8/0x6a0)
[<c04325f8>] (oxnas_pcie_probe) from [<c01f2510>] (platform_drv_probe+0x18/0x48)
[<c01f2510>] (platform_drv_probe) from [<c01f1070>] (driver_probe_device+0xd8/0x24c)
[<c01f1070>] (driver_probe_device) from [<c01f1298>] (__driver_attach+0x70/0x94)
[<c01f1298>] (__driver_attach) from [<c01ef728>] (bus_for_each_dev+0x4c/0x98)
[<c01ef728>] (bus_for_each_dev) from [<c01f0818>] (bus_add_driver+0xcc/0x1e8)
[<c01f0818>] (bus_add_driver) from [<c01f169c>] (driver_register+0xa0/0xe8)
[<c01f169c>] (driver_register) from [<c01f2568>] (platform_driver_probe+0x20/0xa4)
[<c01f2568>] (platform_driver_probe) from [<c0013a3c>] (do_one_initcall+0x90/0x140)
[<c0013a3c>] (do_one_initcall) from [<c0421d38>] (kernel_init_freeable+0x1e4/0x2c0)
[<c0421d38>] (kernel_init_freeable) from [<c000c214>] (kernel_init+0x8/0x104)
[<c000c214>] (kernel_init) from [<c0008768>] (ret_from_fork+0x14/0x2c)
---[ end trace 5f17ed2f61e0683f ]---

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

SVN-Revision: 43787
This commit is contained in:
Felix Fietkau 2014-12-27 13:03:12 +00:00
parent 604fc8faf5
commit 2ef587a8fc
1 changed files with 55 additions and 20 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

75
target/linux/oxnas/files/drivers/clk/clk-oxnas.c
View file

@ -28,6 +28,14 @@
#define MHZ (1000 * 1000)
struct clk_oxnas_pllb {
struct clk_hw hw;
struct device_node *devnode;
struct reset_control *rstc;
};
#define to_clk_oxnas_pllb(_hw) container_of(_hw, struct clk_oxnas_pllb, hw)
static unsigned long plla_clk_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
@ -67,48 +75,72 @@ static struct clk_hw plla_hw = {
.init = &clk_plla_init,
};
static struct device_node *node_pllb;
int pllb_clk_enable(struct clk_hw *hw)
static int pllb_clk_is_prepared(struct clk_hw *hw)
{
struct reset_control *rstc;
struct clk_oxnas_pllb *pllb = to_clk_oxnas_pllb(hw);
rstc = of_reset_control_get(node_pllb, NULL);
if (IS_ERR(rstc))
return PTR_ERR(rstc);
return !!pllb->rstc;
}
static int pllb_clk_prepare(struct clk_hw *hw)
{
struct clk_oxnas_pllb *pllb = to_clk_oxnas_pllb(hw);
pllb->rstc = of_reset_control_get(pllb->devnode, NULL);
return IS_ERR(pllb->rstc) ? PTR_ERR(pllb->rstc) : 0;
}
static void pllb_clk_unprepare(struct clk_hw *hw)
{
struct clk_oxnas_pllb *pllb = to_clk_oxnas_pllb(hw);
BUG_ON(IS_ERR(pllb->rstc));
reset_control_put(pllb->rstc);
pllb->rstc = NULL;
}
static int pllb_clk_enable(struct clk_hw *hw)
{
struct clk_oxnas_pllb *pllb = to_clk_oxnas_pllb(hw);
BUG_ON(IS_ERR(pllb->rstc));
/* put PLL into bypass */
oxnas_register_set_mask(SEC_CTRL_PLLB_CTRL0, BIT(PLLB_BYPASS));
wmb();
udelay(10);
reset_control_assert(rstc);
reset_control_assert(pllb->rstc);
udelay(10);
/* set PLL B control information */
writel((1 << PLLB_ENSAT) | (1 << PLLB_OUTDIV) | (2 << PLLB_REFDIV),
SEC_CTRL_PLLB_CTRL0);
reset_control_deassert(rstc);
reset_control_put(rstc);
reset_control_deassert(pllb->rstc);
udelay(100);
oxnas_register_clear_mask(SEC_CTRL_PLLB_CTRL0, BIT(PLLB_BYPASS));
return 0;
}
void pllb_clk_disable(struct clk_hw *hw)
static void pllb_clk_disable(struct clk_hw *hw)
{
struct reset_control *rstc;
struct clk_oxnas_pllb *pllb = to_clk_oxnas_pllb(hw);
BUG_ON(IS_ERR(pllb->rstc));
/* put PLL into bypass */
oxnas_register_set_mask(SEC_CTRL_PLLB_CTRL0, BIT(PLLB_BYPASS));
wmb();
udelay(10);
rstc = of_reset_control_get(node_pllb, NULL);
if (!IS_ERR(rstc))
reset_control_assert(rstc);
reset_control_assert(pllb->rstc);
}
static struct clk_ops pllb_ops = {
.prepare = pllb_clk_prepare,
.unprepare = pllb_clk_unprepare,
.is_prepared = pllb_clk_is_prepared,
.enable = pllb_clk_enable,
.disable = pllb_clk_disable,
};
@ -120,9 +152,6 @@ static struct clk_init_data clk_pllb_init = {
.num_parents = ARRAY_SIZE(pll_clk_parents),
};
static struct clk_hw pllb_hw = {
.init = &clk_pllb_init,
};
/* standard gate clock */
struct clk_std {
@ -252,10 +281,16 @@ CLK_OF_DECLARE(oxnas_plla, "plxtech,nas782x-plla", oxnas_init_plla);
void __init oxnas_init_pllb(struct device_node *np)
{
struct clk *clk;
struct clk_oxnas_pllb *pllb;
node_pllb = np;
pllb = kmalloc(sizeof(*pllb), GFP_KERNEL);
BUG_ON(!pllb);
clk = clk_register(NULL, &pllb_hw);
pllb->hw.init = &clk_pllb_init;
pllb->devnode = np;
pllb->rstc = NULL;
clk = clk_register(NULL, &pllb->hw);
BUG_ON(IS_ERR(clk));
of_clk_add_provider(np, of_clk_src_simple_get, clk);
}