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    Subject[PATCH 13/22] msm: clock: Push down clock count and locking into sub drivers
    Date
    The clock voting code will need to call clk_set_rate() from
    within a spinlock so we must push down the refcount and lock into
    each sub driver to avoid recursive locking.

    Reviewed-by: Saravana Kannan <skannan@codeaurora.org>
    Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
    ---
    arch/arm/mach-msm/clock-local.c | 3 +-
    arch/arm/mach-msm/clock-pcom.c | 59 ++++++++++++++++++++++++++++++++++----
    arch/arm/mach-msm/clock.c | 32 ++------------------
    arch/arm/mach-msm/clock.h | 1 -
    4 files changed, 58 insertions(+), 37 deletions(-)

    diff --git a/arch/arm/mach-msm/clock-local.c b/arch/arm/mach-msm/clock-local.c
    index f80efa6..86b5a9d 100644
    --- a/arch/arm/mach-msm/clock-local.c
    +++ b/arch/arm/mach-msm/clock-local.c
    @@ -501,7 +501,8 @@ void local_clk_auto_off(unsigned id)
    return;

    spin_lock_irqsave(&local_clock_reg_lock, flags);
    - local_clk_disable_reg(id);
    + if (clk->count == 0)
    + local_clk_disable_reg(id);
    spin_unlock_irqrestore(&local_clock_reg_lock, flags);
    }

    diff --git a/arch/arm/mach-msm/clock-pcom.c b/arch/arm/mach-msm/clock-pcom.c
    index 2f9d0d4..358e065 100644
    --- a/arch/arm/mach-msm/clock-pcom.c
    +++ b/arch/arm/mach-msm/clock-pcom.c
    @@ -16,27 +16,72 @@
    #include <linux/err.h>
    #include <linux/ctype.h>
    #include <linux/stddef.h>
    +#include <linux/spinlock.h>
    +
    #include <mach/clk.h>

    #include "proc_comm.h"
    #include "clock.h"
    #include "clock-pcom.h"

    +struct clk_pcom {
    + unsigned count;
    +};
    +
    +static struct clk_pcom pcom_clocks[P_NR_CLKS];
    +
    +static DEFINE_SPINLOCK(pc_clk_lock);
    +
    /*
    * glue for the proc_comm interface
    */
    int pc_clk_enable(unsigned id)
    {
    - int rc = msm_proc_comm(PCOM_CLKCTL_RPC_ENABLE, &id, NULL);
    - if (rc < 0)
    - return rc;
    - else
    - return (int)id < 0 ? -EINVAL : 0;
    + int rc;
    + unsigned long flags;
    + struct clk_pcom *clk = &pcom_clocks[id];
    +
    + spin_lock_irqsave(&pc_clk_lock, flags);
    + if (clk->count == 0) {
    + rc = msm_proc_comm(PCOM_CLKCTL_RPC_ENABLE, &id, NULL);
    + if (rc < 0)
    + goto unlock;
    + else if ((int)id < 0) {
    + rc = -EINVAL;
    + goto unlock;
    + } else
    + rc = 0;
    + }
    + clk->count++;
    +unlock:
    + spin_unlock_irqrestore(&pc_clk_lock, flags);
    + return rc;
    }

    void pc_clk_disable(unsigned id)
    {
    - msm_proc_comm(PCOM_CLKCTL_RPC_DISABLE, &id, NULL);
    + unsigned long flags;
    + struct clk_pcom *clk = &pcom_clocks[id];
    +
    + spin_lock_irqsave(&pc_clk_lock, flags);
    + if (WARN_ON(clk->count == 0))
    + goto out;
    + clk->count--;
    + if (clk->count == 0)
    + msm_proc_comm(PCOM_CLKCTL_RPC_DISABLE, &id, NULL);
    +out:
    + spin_unlock_irqrestore(&pc_clk_lock, flags);
    +}
    +
    +void pc_clk_auto_off(unsigned id)
    +{
    + unsigned long flags;
    + struct clk_pcom *clk = &pcom_clocks[id];
    +
    + spin_lock_irqsave(&pc_clk_lock, flags);
    + if (clk->count == 0)
    + msm_proc_comm(PCOM_CLKCTL_RPC_DISABLE, &id, NULL);
    + spin_unlock_irqrestore(&pc_clk_lock, flags);
    }

    int pc_clk_reset(unsigned id, enum clk_reset_action action)
    @@ -131,7 +176,7 @@ static bool pc_clk_is_local(unsigned id)
    struct clk_ops clk_ops_pcom = {
    .enable = pc_clk_enable,
    .disable = pc_clk_disable,
    - .auto_off = pc_clk_disable,
    + .auto_off = pc_clk_auto_off,
    .reset = pc_clk_reset,
    .set_rate = pc_clk_set_rate,
    .set_min_rate = pc_clk_set_min_rate,
    diff --git a/arch/arm/mach-msm/clock.c b/arch/arm/mach-msm/clock.c
    index 06cd313..80e1d64 100644
    --- a/arch/arm/mach-msm/clock.c
    +++ b/arch/arm/mach-msm/clock.c
    @@ -23,7 +23,6 @@
    #include "clock.h"

    static DEFINE_MUTEX(clocks_mutex);
    -static DEFINE_SPINLOCK(clocks_lock);
    static LIST_HEAD(clocks);

    /*
    @@ -57,25 +56,13 @@ EXPORT_SYMBOL(clk_put);

    int clk_enable(struct clk *clk)
    {
    - unsigned long flags;
    - spin_lock_irqsave(&clocks_lock, flags);
    - clk->count++;
    - if (clk->count == 1)
    - clk->ops->enable(clk->id);
    - spin_unlock_irqrestore(&clocks_lock, flags);
    - return 0;
    + return clk->ops->enable(clk->id);
    }
    EXPORT_SYMBOL(clk_enable);

    void clk_disable(struct clk *clk)
    {
    - unsigned long flags;
    - spin_lock_irqsave(&clocks_lock, flags);
    - BUG_ON(clk->count == 0);
    - clk->count--;
    - if (clk->count == 0)
    - clk->ops->disable(clk->id);
    - spin_unlock_irqrestore(&clocks_lock, flags);
    + clk->ops->disable(clk->id);
    }
    EXPORT_SYMBOL(clk_disable);

    @@ -182,27 +169,16 @@ void __init msm_clock_init(struct clk *clock_tbl, unsigned num_clocks)
    */
    static int __init clock_late_init(void)
    {
    - unsigned long flags;
    struct clk *clk;
    - unsigned count = 0;

    clock_debug_init();
    mutex_lock(&clocks_mutex);
    list_for_each_entry(clk, &clocks, list) {
    clock_debug_add(clk);
    - if (clk->flags & CLKFLAG_AUTO_OFF) {
    - spin_lock_irqsave(&clocks_lock, flags);
    - if (!clk->count) {
    - count++;
    - clk->ops->auto_off(clk->id);
    - }
    - spin_unlock_irqrestore(&clocks_lock, flags);
    - }
    + if (clk->flags & CLKFLAG_AUTO_OFF)
    + clk->ops->auto_off(clk->id);
    }
    mutex_unlock(&clocks_mutex);
    - pr_info("clock_late_init() disabled %d unused clocks\n", count);
    return 0;
    }
    -
    late_initcall(clock_late_init);
    -
    diff --git a/arch/arm/mach-msm/clock.h b/arch/arm/mach-msm/clock.h
    index 67f9d9e..4dc8853 100644
    --- a/arch/arm/mach-msm/clock.h
    +++ b/arch/arm/mach-msm/clock.h
    @@ -51,7 +51,6 @@ struct clk_ops {
    struct clk {
    uint32_t id;
    uint32_t remote_id;
    - uint32_t count;
    uint32_t flags;
    const char *name;
    struct clk_ops *ops;
    --
    Sent by an employee of the Qualcomm Innovation Center, Inc.
    The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.


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