From: Stephen Boyd <sboyd@codeaurora.org> To: linux-arm-msm@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mike Turquette <mturquette@linaro.org> Subject: [RFC/PATCH 02/12] clk: Add safe switch hook Date: Tue, 24 Jun 2014 17:06:13 -0700 [thread overview] Message-ID: <1403654783-7176-3-git-send-email-sboyd@codeaurora.org> (raw) In-Reply-To: <1403654783-7176-1-git-send-email-sboyd@codeaurora.org> Sometimes clocks can't accept their parent source turning off while the source is reprogrammed to a different rate. Most notably some CPU clocks require a way to switch away from the current PLL they're running on, reprogram that PLL to a new rate, and then switch back to the PLL with the new rate once they're done. Add a hook that drivers can implement allowing them to return a 'safe parent' that they can switch their parent to while the upstream source is reprogrammed. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> --- drivers/clk/clk.c | 53 ++++++++++++++++++++++++++++++++++++++------ include/linux/clk-private.h | 2 ++ include/linux/clk-provider.h | 1 + 3 files changed, 49 insertions(+), 7 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 8b73edef151d..5e32fa55032b 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1367,6 +1367,7 @@ static void clk_calc_subtree(struct clk *clk, unsigned long new_rate, struct clk *new_parent, u8 p_index) { struct clk *child; + struct clk *parent; clk->new_rate = new_rate; clk->new_parent = new_parent; @@ -1376,6 +1377,17 @@ static void clk_calc_subtree(struct clk *clk, unsigned long new_rate, if (new_parent && new_parent != clk->parent) new_parent->new_child = clk; + if (clk->ops->get_safe_parent) { + parent = clk->ops->get_safe_parent(clk->hw); + if (parent) { + p_index = clk_fetch_parent_index(clk, parent); + clk->safe_parent_index = p_index; + clk->safe_parent = parent; + } + } else { + clk->safe_parent = NULL; + } + hlist_for_each_entry(child, &clk->children, child_node) { child->new_rate = clk_recalc(child, new_rate); clk_calc_subtree(child, child->new_rate, NULL, 0); @@ -1458,14 +1470,42 @@ out: static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event) { struct clk *child, *tmp_clk, *fail_clk = NULL; + struct clk *old_parent; int ret = NOTIFY_DONE; - if (clk->rate == clk->new_rate) + if (clk->rate == clk->new_rate && event != POST_RATE_CHANGE) return NULL; + switch (event) { + case PRE_RATE_CHANGE: + if (clk->safe_parent) + clk->ops->set_parent(clk->hw, clk->safe_parent_index); + break; + case POST_RATE_CHANGE: + if (clk->safe_parent) { + old_parent = __clk_set_parent_before(clk, + clk->new_parent); + if (clk->ops->set_rate_and_parent) { + clk->ops->set_rate_and_parent(clk->hw, + clk->new_rate, + clk->new_parent ? + clk->new_parent->rate : 0, + clk->new_parent_index); + } else if (clk->ops->set_parent) { + clk->ops->set_parent(clk->hw, + clk->new_parent_index); + } + __clk_set_parent_after(clk, clk->new_parent, + old_parent); + } + break; + } + if (clk->notifier_count) { - ret = __clk_notify(clk, event, clk->rate, clk->new_rate); - if (ret & NOTIFY_STOP_MASK) + if (event != POST_RATE_CHANGE) + ret = __clk_notify(clk, event, clk->rate, + clk->new_rate); + if (ret & NOTIFY_STOP_MASK && event != POST_RATE_CHANGE) fail_clk = clk; } @@ -1507,7 +1547,8 @@ static void clk_change_rate(struct clk *clk) else if (clk->parent) best_parent_rate = clk->parent->rate; - if (clk->new_parent && clk->new_parent != clk->parent) { + if (clk->new_parent && clk->new_parent != clk->parent && + !clk->safe_parent) { old_parent = __clk_set_parent_before(clk, clk->new_parent); if (clk->ops->set_rate_and_parent) { @@ -1527,9 +1568,6 @@ static void clk_change_rate(struct clk *clk) clk->rate = clk_recalc(clk, best_parent_rate); - if (clk->notifier_count && old_rate != clk->rate) - __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate); - hlist_for_each_entry(child, &clk->children, child_node) { /* Skip children who will be reparented to another clock */ if (child->new_parent && child->new_parent != clk) @@ -1603,6 +1641,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate) /* change the rates */ clk_change_rate(top); + clk_propagate_rate_change(top, POST_RATE_CHANGE); out: clk_prepare_unlock(); diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h index efbf70b9fd84..f48684af4d8f 100644 --- a/include/linux/clk-private.h +++ b/include/linux/clk-private.h @@ -38,8 +38,10 @@ struct clk { struct clk **parents; u8 num_parents; u8 new_parent_index; + u8 safe_parent_index; unsigned long rate; unsigned long new_rate; + struct clk *safe_parent; struct clk *new_parent; struct clk *new_child; unsigned long flags; diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 0c287dbbb144..7485911df4b6 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -170,6 +170,7 @@ struct clk_ops { struct clk **best_parent_clk); int (*set_parent)(struct clk_hw *hw, u8 index); u8 (*get_parent)(struct clk_hw *hw); + struct clk *(*get_safe_parent)(struct clk_hw *hw); int (*set_rate)(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate); int (*set_rate_and_parent)(struct clk_hw *hw, -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation
WARNING: multiple messages have this Message-ID (diff)
From: sboyd@codeaurora.org (Stephen Boyd) To: linux-arm-kernel@lists.infradead.org Subject: [RFC/PATCH 02/12] clk: Add safe switch hook Date: Tue, 24 Jun 2014 17:06:13 -0700 [thread overview] Message-ID: <1403654783-7176-3-git-send-email-sboyd@codeaurora.org> (raw) In-Reply-To: <1403654783-7176-1-git-send-email-sboyd@codeaurora.org> Sometimes clocks can't accept their parent source turning off while the source is reprogrammed to a different rate. Most notably some CPU clocks require a way to switch away from the current PLL they're running on, reprogram that PLL to a new rate, and then switch back to the PLL with the new rate once they're done. Add a hook that drivers can implement allowing them to return a 'safe parent' that they can switch their parent to while the upstream source is reprogrammed. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> --- drivers/clk/clk.c | 53 ++++++++++++++++++++++++++++++++++++++------ include/linux/clk-private.h | 2 ++ include/linux/clk-provider.h | 1 + 3 files changed, 49 insertions(+), 7 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 8b73edef151d..5e32fa55032b 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1367,6 +1367,7 @@ static void clk_calc_subtree(struct clk *clk, unsigned long new_rate, struct clk *new_parent, u8 p_index) { struct clk *child; + struct clk *parent; clk->new_rate = new_rate; clk->new_parent = new_parent; @@ -1376,6 +1377,17 @@ static void clk_calc_subtree(struct clk *clk, unsigned long new_rate, if (new_parent && new_parent != clk->parent) new_parent->new_child = clk; + if (clk->ops->get_safe_parent) { + parent = clk->ops->get_safe_parent(clk->hw); + if (parent) { + p_index = clk_fetch_parent_index(clk, parent); + clk->safe_parent_index = p_index; + clk->safe_parent = parent; + } + } else { + clk->safe_parent = NULL; + } + hlist_for_each_entry(child, &clk->children, child_node) { child->new_rate = clk_recalc(child, new_rate); clk_calc_subtree(child, child->new_rate, NULL, 0); @@ -1458,14 +1470,42 @@ out: static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event) { struct clk *child, *tmp_clk, *fail_clk = NULL; + struct clk *old_parent; int ret = NOTIFY_DONE; - if (clk->rate == clk->new_rate) + if (clk->rate == clk->new_rate && event != POST_RATE_CHANGE) return NULL; + switch (event) { + case PRE_RATE_CHANGE: + if (clk->safe_parent) + clk->ops->set_parent(clk->hw, clk->safe_parent_index); + break; + case POST_RATE_CHANGE: + if (clk->safe_parent) { + old_parent = __clk_set_parent_before(clk, + clk->new_parent); + if (clk->ops->set_rate_and_parent) { + clk->ops->set_rate_and_parent(clk->hw, + clk->new_rate, + clk->new_parent ? + clk->new_parent->rate : 0, + clk->new_parent_index); + } else if (clk->ops->set_parent) { + clk->ops->set_parent(clk->hw, + clk->new_parent_index); + } + __clk_set_parent_after(clk, clk->new_parent, + old_parent); + } + break; + } + if (clk->notifier_count) { - ret = __clk_notify(clk, event, clk->rate, clk->new_rate); - if (ret & NOTIFY_STOP_MASK) + if (event != POST_RATE_CHANGE) + ret = __clk_notify(clk, event, clk->rate, + clk->new_rate); + if (ret & NOTIFY_STOP_MASK && event != POST_RATE_CHANGE) fail_clk = clk; } @@ -1507,7 +1547,8 @@ static void clk_change_rate(struct clk *clk) else if (clk->parent) best_parent_rate = clk->parent->rate; - if (clk->new_parent && clk->new_parent != clk->parent) { + if (clk->new_parent && clk->new_parent != clk->parent && + !clk->safe_parent) { old_parent = __clk_set_parent_before(clk, clk->new_parent); if (clk->ops->set_rate_and_parent) { @@ -1527,9 +1568,6 @@ static void clk_change_rate(struct clk *clk) clk->rate = clk_recalc(clk, best_parent_rate); - if (clk->notifier_count && old_rate != clk->rate) - __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate); - hlist_for_each_entry(child, &clk->children, child_node) { /* Skip children who will be reparented to another clock */ if (child->new_parent && child->new_parent != clk) @@ -1603,6 +1641,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate) /* change the rates */ clk_change_rate(top); + clk_propagate_rate_change(top, POST_RATE_CHANGE); out: clk_prepare_unlock(); diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h index efbf70b9fd84..f48684af4d8f 100644 --- a/include/linux/clk-private.h +++ b/include/linux/clk-private.h @@ -38,8 +38,10 @@ struct clk { struct clk **parents; u8 num_parents; u8 new_parent_index; + u8 safe_parent_index; unsigned long rate; unsigned long new_rate; + struct clk *safe_parent; struct clk *new_parent; struct clk *new_child; unsigned long flags; diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 0c287dbbb144..7485911df4b6 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -170,6 +170,7 @@ struct clk_ops { struct clk **best_parent_clk); int (*set_parent)(struct clk_hw *hw, u8 index); u8 (*get_parent)(struct clk_hw *hw); + struct clk *(*get_safe_parent)(struct clk_hw *hw); int (*set_rate)(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate); int (*set_rate_and_parent)(struct clk_hw *hw, -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation
next prev parent reply other threads:[~2014-06-25 0:06 UTC|newest] Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-06-25 0:06 [RFC/PATCH 00/12] Krait clocks + Krait CPUfreq Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:06 ` [RFC/PATCH 01/12] ARM: Add Krait L2 register accessor functions Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd [this message] 2014-06-25 0:06 ` [RFC/PATCH 02/12] clk: Add safe switch hook Stephen Boyd 2014-07-29 6:05 ` Mike Turquette 2014-07-29 6:05 ` Mike Turquette 2014-07-29 8:59 ` Thomas Abraham 2014-07-29 8:59 ` Thomas Abraham 2014-07-29 8:59 ` Thomas Abraham 2014-09-10 1:44 ` dbasehore . 2014-09-10 1:44 ` dbasehore . 2014-09-10 1:44 ` dbasehore . 2014-06-25 0:06 ` [RFC/PATCH 03/12] clk: qcom: Add support for muxes, dividers, and mux dividers Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-07-14 10:06 ` pramod gurav 2014-07-14 10:06 ` pramod gurav 2014-06-25 0:06 ` [RFC/PATCH 04/12] clk: qcom: Add support for High-Frequency PLLs (HFPLLs) Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:06 ` [RFC/PATCH 05/12] clk: qcom: Add HFPLL driver Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:06 ` [RFC/PATCH 06/12] clk: qcom: Add MSM8960's HFPLLs Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-07-14 10:19 ` pramod gurav 2014-07-14 10:19 ` pramod gurav 2014-06-25 0:06 ` [RFC/PATCH 07/12] clk: qcom: Add support for Krait clocks Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:06 ` [RFC/PATCH 08/12] clk: qcom: Add KPSS ACC/GCC driver Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:06 ` [RFC/PATCH 09/12] clk: qcom: Add Krait clock controller driver Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-07-14 10:25 ` pramod gurav 2014-07-14 10:25 ` pramod gurav 2014-06-25 0:06 ` [RFC/PATCH 10/12] cpufreq: Add a cpufreq-krait based on cpufreq-cpu0 Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:52 ` Stephen Boyd 2014-06-25 0:52 ` Stephen Boyd 2014-06-25 8:47 ` Viresh Kumar 2014-06-25 8:47 ` Viresh Kumar 2014-06-25 8:47 ` Viresh Kumar 2014-06-25 0:06 ` [RFC/PATCH 11/12] cpufreq: Add module to register cpufreq-krait device Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-06-25 0:06 ` [RFC/PATCH 12/12] ARM: dts: qcom: Add necessary DT data for Krait cpufreq Stephen Boyd 2014-06-25 0:06 ` Stephen Boyd 2014-07-15 10:33 ` [RFC/PATCH 00/12] Krait clocks + Krait CPUfreq pramod gurav 2014-07-15 10:33 ` pramod gurav
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1403654783-7176-3-git-send-email-sboyd@codeaurora.org \ --to=sboyd@codeaurora.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-arm-msm@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=mturquette@linaro.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.