Re: [PATCH 1/2] clk: qcom: clk-rpmh: Add QCOM RPMh clock driver

Taniya Das
2018-04-02T10:33:37Z

Hello Evan,

Thanks for the review comments.

On 3/30/2018 3:19 AM, Evan Green wrote:
> Hi Taniya,
>
> On Wed, Mar 28, 2018 at 11:19 PM Taniya Das <tdas@codeaurora.org> wrote:
>
>> From: Amit Nischal <anischal@codeaurora.org>
>
>> Add the RPMh clock driver to control the RPMh managed clock resources on
>> some of the Qualcomm Technologies, Inc. SoCs.
>
>> Signed-off-by: David Collins <collinsd@codeaurora.org>
>> Signed-off-by: Amit Nischal <anischal@codeaurora.org>
>> Signed-off-by: Taniya Das <tdas@codeaurora.org>
>> ---
>> drivers/clk/qcom/Kconfig | 9 +
>> drivers/clk/qcom/Makefile | 1 +
>> drivers/clk/qcom/clk-rpmh.c | 397
> ++++++++++++++++++++++++++++++++++
>> include/dt-bindings/clock/qcom,rpmh.h | 25 +++
>> 4 files changed, 432 insertions(+)
>> create mode 100644 drivers/clk/qcom/clk-rpmh.c
>> create mode 100644 include/dt-bindings/clock/qcom,rpmh.h
>
>> diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
> ...
>> diff --git a/drivers/clk/qcom/clk-rpmh.c b/drivers/clk/qcom/clk-rpmh.c
>> new file mode 100644
>> index 0000000..536d102
>> --- /dev/null
>> +++ b/drivers/clk/qcom/clk-rpmh.c
>> @@ -0,0 +1,397 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
>> + */
>> +
>> +#define pr_fmt(fmt) "%s: " fmt, __func__
>
> Stanimir recently commented on a different patch asking for using dev_*
> instead of this. Seems like an applicable comment here, too.
>

I will drop this to see how I could accomodate dev_xxx.

>> +
>> +#include <linux/kernel.h>
>> +#include <linux/err.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/clk.h>
>> +#include <linux/clk-provider.h>
>> +#include <linux/regmap.h>
>> +#include <soc/qcom/cmd-db.h>
>> +#include <soc/qcom/rpmh.h>
>> +#include <dt-bindings/clock/qcom,rpmh.h>
>
> Alphabetize includes?

I will take care of them in the next patch series.

>
>> +
>> +#include "common.h"
>> +#include "clk-regmap.h"
>> +
>> +#define CLK_RPMH_ARC_EN_OFFSET 0
>> +#define CLK_RPMH_VRM_EN_OFFSET 4
>> +#define CLK_RPMH_VRM_OFF_VAL 0
>> +#define CLK_RPMH_VRM_ON_VAL 1
>> +#define CLK_RPMH_APPS_RSC_AO_STATE_MASK (BIT(RPMH_WAKE_ONLY_STATE) | \
>> + BIT(RPMH_ACTIVE_ONLY_STATE))
>> +#define CLK_RPMH_APPS_RSC_STATE_MASK (BIT(RPMH_WAKE_ONLY_STATE) | \
>> + BIT(RPMH_ACTIVE_ONLY_STATE) | \
>> + BIT(RPMH_SLEEP_STATE))
>> +struct clk_rpmh {
>> + const char *res_name;
>> + u32 res_addr;
>> + u32 res_en_offset;
>> + u32 res_on_val;
>> + u32 res_off_val;
>> + u32 state;
>> + u32 aggr_state;
>> + u32 last_sent_aggr_state;
>> + u32 valid_state_mask;
>> + struct rpmh_client *rpmh_client;
>> + unsigned long rate;
>> + struct clk_rpmh *peer;
>> + struct clk_hw hw;
>
> I believe this member should go at the beginning of the structure. At least
> that's what everyone else seems to do, and that's what the clk.txt
> documentation seems to ask for.
>

Yes I missed that, would update it in the next patch series.

>> +};
>> +
>> +struct rpmh_cc {
>> + struct clk_onecell_data data;
>> + struct clk *clks[];
>> +};
>> +
>> +struct clk_rpmh_desc {
>> + struct clk_hw **clks;
>> + size_t num_clks;
>> +};
>> +
>> +static DEFINE_MUTEX(rpmh_clk_lock);
>> +
>> +#define __DEFINE_CLK_RPMH(_platform, _name, _name_active, _res_name, \
>> + _res_en_offset, _res_on, _res_off, _rate, \
>> + _state_mask, _state_on_mask)
> \
>> + static struct clk_rpmh _platform##_##_name_active;
> \
>> + static struct clk_rpmh _platform##_##_name = {
> \
>> + .res_name = _res_name,
> \
>> + .res_en_offset = _res_en_offset,
> \
>> + .res_on_val = _res_on,
> \
>> + .res_off_val = _res_off,
> \
>> + .rate = _rate,
> \
>> + .peer = &_platform##_##_name_active,
> \
>> + .valid_state_mask = _state_mask,
> \
>> + .hw.init = &(struct clk_init_data){
> \
>> + .ops = &clk_rpmh_ops,
> \
>> + .name = #_name,
> \
>> + },
> \
>> + };
> \
>> + static struct clk_rpmh _platform##_##_name_active = {
> \
>> + .res_name = _res_name,
> \
>> + .res_en_offset = _res_en_offset,
> \
>> + .res_on_val = _res_on,
> \
>> + .res_off_val = _res_off,
> \
>> + .rate = _rate,
> \
>> + .peer = &_platform##_##_name,
> \
>> + .valid_state_mask = _state_on_mask,
> \
>> + .hw.init = &(struct clk_init_data){
> \
>> + .ops = &clk_rpmh_ops,
> \
>> + .name = #_name_active,
> \
>> + },
> \
>> + }
>> +
>> +#define DEFINE_CLK_RPMH_ARC(_platform, _name, _name_active, _res_name, \
>> + _res_on, _res_off, _rate, _state_mask, \
>> + _state_on_mask) \
>> + __DEFINE_CLK_RPMH(_platform, _name, _name_active, _res_name, \
>> + CLK_RPMH_ARC_EN_OFFSET, _res_on, _res_off, \
>> + _rate, _state_mask, _state_on_mask)
>> +
>> +#define DEFINE_CLK_RPMH_VRM(_platform, _name, _name_active, _res_name, \
>> + _rate, _state_mask, _state_on_mask) \
>> + __DEFINE_CLK_RPMH(_platform, _name, _name_active, _res_name, \
>> + CLK_RPMH_VRM_EN_OFFSET, CLK_RPMH_VRM_ON_VAL, \
>> + CLK_RPMH_VRM_OFF_VAL, _rate, _state_mask, \
>> + _state_on_mask)
>> +
>> +static inline struct clk_rpmh *to_clk_rpmh(struct clk_hw *_hw)
>> +{
>> + return container_of(_hw, struct clk_rpmh, hw);
>> +}
>> +
>> +static inline bool has_state_changed(struct clk_rpmh *c, u32 state)
>> +{
>> + return ((c->last_sent_aggr_state & BIT(state))
>> + != (c->aggr_state & BIT(state)));
>> +}
>> +
>> +static int clk_rpmh_send_aggregate_command(struct clk_rpmh *c)
>> +{
>> + struct tcs_cmd cmd = { 0 };
>> + int ret = 0;
>> +
>> + cmd.addr = c->res_addr + c->res_en_offset;
>> +
>> + if (has_state_changed(c, RPMH_SLEEP_STATE)) {
>> + cmd.data = (c->aggr_state >> RPMH_SLEEP_STATE) & 1
>> + ? c->res_on_val : c->res_off_val;
>
> I found it quite confusing that you're shifting in the opposite direction
> than in has_state_changed. How about this:
>
> cmd.data = (c->aggr_state & BIT(RPMH_SLEEP_STATE)) ? c->res_on_val :
> c->res_off_val;
>

It is kept keeping in mind the consistency of the command data for all
the different states.

Would it be better if I define a new macro ?

#define RPMH_CMD_DATA(aggr_state, rpmh_state) \
((aggr_state >> rpmh_state) & 1)

If you agree, I could use the new macro in the next series.

>> + ret = rpmh_write_async(c->rpmh_client, RPMH_SLEEP_STATE,
>> + &cmd, 1);
>> + if (ret) {
>> + pr_err("rpmh_write_async(%s, state=%d) failed
> (%d)\n",
>> + c->res_name, RPMH_SLEEP_STATE, ret);
>> + return ret;
>> + }
>> + }
>> +
>> + if (has_state_changed(c, RPMH_WAKE_ONLY_STATE)) {
>> + cmd.data = (c->aggr_state >> RPMH_WAKE_ONLY_STATE) & 1
>> + ? c->res_on_val : c->res_off_val;
>> + ret = rpmh_write_async(c->rpmh_client,
>> + RPMH_WAKE_ONLY_STATE, &cmd, 1);
>> + if (ret) {
>> + pr_err("rpmh_write_async(%s, state=%d) failed
> (%d)\n",
>> + c->res_name, RPMH_WAKE_ONLY_STATE, ret);
>> + return ret;
>> + }
>> + }
>> +
>> + if (has_state_changed(c, RPMH_ACTIVE_ONLY_STATE)) {
>> + cmd.data = (c->aggr_state >> RPMH_ACTIVE_ONLY_STATE) & 1
>> + ? c->res_on_val : c->res_off_val;
>> + ret = rpmh_write(c->rpmh_client, RPMH_ACTIVE_ONLY_STATE,
>> + &cmd, 1);
>> + if (ret) {
>> + pr_err("rpmh_write(%s, state=%d) failed (%d)\n",
>> + c->res_name, RPMH_ACTIVE_ONLY_STATE, ret);
>> + return ret;
>> + }
>> + }
>> +
>> + c->last_sent_aggr_state = c->aggr_state;
>> + c->peer->last_sent_aggr_state = c->last_sent_aggr_state;
>> +
>> + return 0;
>> +}
>> +
>> +static void clk_rpmh_aggregate_state(struct clk_rpmh *c, bool enable)
>> +{
>> + /* Update state and aggregate state values based on enable value.
> */
>> + c->state = enable ? c->valid_state_mask : 0;
>> + c->aggr_state = c->state | c->peer->state;
>> + c->peer->aggr_state = c->aggr_state;
>> +}
>> +
>> +static int clk_rpmh_prepare(struct clk_hw *hw)
>> +{
>> + struct clk_rpmh *c = to_clk_rpmh(hw);
>> + int ret = 0;
>> +
>> + mutex_lock(&rpmh_clk_lock);
>> +
>> + if (c->state)
>> + goto out;
>> +
>> + clk_rpmh_aggregate_state(c, true);
>> +
>> + ret = clk_rpmh_send_aggregate_command(c);
>> +
>> + if (ret)
>> + c->state = 0;
>> +
>> +out:
>> + mutex_unlock(&rpmh_clk_lock);
>> + return ret;
>> +};
>> +
>> +static void clk_rpmh_unprepare(struct clk_hw *hw)
>> +{
>> + struct clk_rpmh *c = to_clk_rpmh(hw);
>> + int ret = 0;
>> +
>> + mutex_lock(&rpmh_clk_lock);
>> +
>> + if (!c->state)
>> + goto out;
>> +
>> + clk_rpmh_aggregate_state(c, false);
>> +
>> + ret = clk_rpmh_send_aggregate_command(c);
>> +
>> + if (ret) {
>> + c->state = c->valid_state_mask;
>> + WARN(1, "clk: %s failed to disable\n", c->res_name);
>> + }
>> +
>> +out:
>> + mutex_unlock(&rpmh_clk_lock);
>> + return;
>> +};
>
> The guts of these two functions (clk_rpmh_{un,}prepare) look like they
> would collapse pretty well into a single helper function that takes an
> extra enable parameter. The if would change to !!c->state == enable,
> clk_rpmh_aggregate_state would take the enable parameter, and the failure
> case could restore a previously saved value. And you could just ditch the
> WARN entirely (probably should do that anyway). Not critical though, up to
> you.
>
> ...
>

I would have a new helper function, would update in the next series.

>> +
>> +static int clk_rpmh_probe(struct platform_device *pdev)
>> +{
>> + struct clk **clks;
>> + struct clk *clk;
>> + struct rpmh_cc *rcc;
>> + struct clk_onecell_data *data;
>> + int ret;
>> + size_t num_clks, i;
>> + struct clk_hw **hw_clks;
>> + struct clk_rpmh *rpmh_clk;
>> + const struct clk_rpmh_desc *desc;
>> + struct property *prop;
>
> Remove this unused variable. It generates a warning (or an error for some
> of us).
> ...

Would clean the unused variables.

>> diff --git a/include/dt-bindings/clock/qcom,rpmh.h
> b/include/dt-bindings/clock/qcom,rpmh.h
>> new file mode 100644
>> index 0000000..34fbf3c
>> --- /dev/null
>> +++ b/include/dt-bindings/clock/qcom,rpmh.h
>> @@ -0,0 +1,25 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
>> + */
>> +
>> +#ifndef _DT_BINDINGS_CLK_MSM_RPMH_H
>> +#define _DT_BINDINGS_CLK_MSM_RPMH_H
>
> Maybe _DT_BINDINGS_CLK_QCOM_RPMH_H instead?
>

Kept inline with the other target header files.

> -Evan
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