Re: [[PATCH v2] 1/2] clk: qcom: clk-rpmh: Add QCOM RPMh clock driver

[Bjorn Andersson]

On Sun 08 Apr 03:32 PDT 2018, Taniya Das wrote:

> From: Amit Nischal <anischal@xxxxxxxxxxxxxx>
> 
> 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@xxxxxxxxxxxxxx>
> Signed-off-by: Amit Nischal <anischal@xxxxxxxxxxxxxx>
> Signed-off-by: Taniya Das <tdas@xxxxxxxxxxxxxx>
> ---
>  drivers/clk/qcom/Kconfig              |   9 +
>  drivers/clk/qcom/Makefile             |   1 +
>  drivers/clk/qcom/clk-rpmh.c           | 394 ++++++++++++++++++++++++++++++++++
>  include/dt-bindings/clock/qcom,rpmh.h |  25 +++
>  4 files changed, 429 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
> index fbf4532..3697a6a 100644
> --- a/drivers/clk/qcom/Kconfig
> +++ b/drivers/clk/qcom/Kconfig
> @@ -112,6 +112,15 @@ config IPQ_GCC_8074
>  	  i2c, USB, SD/eMMC, etc. Select this for the root clock
>  	  of ipq8074.
>  
> +config MSM_CLK_RPMH

QCOM_CLK_RPMH

> +	tristate "RPMh Clock Driver"
> +	depends on COMMON_CLK_QCOM && QCOM_RPMH
> +	help
> +	 RPMh manages shared resources on some Qualcomm Technologies, Inc.
> +	 SoCs. It accepts requests from other hardware subsystems via RSC.
> +	 Say Y if you want to support the clocks exposed by RPMh on
> +	 platforms such as sdm845.
> +
>  config MSM_GCC_8660
>  	tristate "MSM8660 Global Clock Controller"
>  	depends on COMMON_CLK_QCOM
> diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
> index 230332c..b7da05b 100644
> --- a/drivers/clk/qcom/Makefile
> +++ b/drivers/clk/qcom/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_IPQ_GCC_8074) += gcc-ipq8074.o
>  obj-$(CONFIG_IPQ_LCC_806X) += lcc-ipq806x.o
>  obj-$(CONFIG_MDM_GCC_9615) += gcc-mdm9615.o
>  obj-$(CONFIG_MDM_LCC_9615) += lcc-mdm9615.o
> +obj-$(CONFIG_MSM_CLK_RPMH) += clk-rpmh.o
>  obj-$(CONFIG_MSM_GCC_8660) += gcc-msm8660.o
>  obj-$(CONFIG_MSM_GCC_8916) += gcc-msm8916.o
>  obj-$(CONFIG_MSM_GCC_8960) += gcc-msm8960.o
> diff --git a/drivers/clk/qcom/clk-rpmh.c b/drivers/clk/qcom/clk-rpmh.c
> new file mode 100644
> index 0000000..763401f
> --- /dev/null
> +++ b/drivers/clk/qcom/clk-rpmh.c
> @@ -0,0 +1,394 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/err.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>

Unused

> +#include <soc/qcom/cmd-db.h>
> +#include <soc/qcom/rpmh.h>
> +
> +#include <dt-bindings/clock/qcom,rpmh.h>
> +
> +#include "common.h"
> +#include "clk-regmap.h"

Unused

> +
> +#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

Use a bool (true/false) rather than lugging around these two defines.

> +#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 {
> +	struct clk_hw hw;
> +	const char *res_name;
> +	u32 res_addr;
> +	u32 res_en_offset;
> +	u32 res_on_val;
> +	u32 res_off_val;

res_off_val is 0 for all clocks.

> +	u32 state;
> +	u32 aggr_state;
> +	u32 last_sent_aggr_state;

Through the use of some local variables you shouldn't have to lug around
aggr_state and last_sent_aggr_state.

> +	u32 valid_state_mask;
> +	struct rpmh_client *rpmh_client;
> +	unsigned long rate;
> +	struct clk_rpmh *peer;
> +};
> +
> +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,			      \

This is always CLK_RPMH_APPS_RSC_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,			      \

and this is always CLK_RPMH_APPS_RSC_AO_STATE_MASK. If you just hard
code them here (until there's a need for them to be anything else) the
clock list below becomes tidier.

> +		.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 & BIT(RPMH_SLEEP_STATE))
> +				? c->res_on_val : c->res_off_val;

As these values are reused several times in this function you could by
using some local variables get this down to the much more readable:

		cmd.data = state & BIT(RPMH_SLEEP_STATE) ? on_val : off_val;

And as off_val is 0 for all your clocks you can even drop the latter.

> +		ret = rpmh_write_async(c->rpmh_client, RPMH_SLEEP_STATE,
> +				       &cmd, 1);
> +		if (ret) {
> +			pr_err("%s: rpmh_write_async(%s, state=%d) failed (%d)\n",
> +			       __func__, c->res_name, RPMH_SLEEP_STATE, ret);

Please drop the __func__, the error string is unique in this driver; and
rather than passing a constant to a %d actually write your error message
in a human readable form, like: "set sleep state of %s failed: %d\n".

And please do carry the struct device, so that you can use dev_err()
instead.

> +			return ret;
> +		}
> +	}
> +
> +	if (has_state_changed(c, RPMH_WAKE_ONLY_STATE)) {
> +		cmd.data = (c->aggr_state & BIT(RPMH_WAKE_ONLY_STATE))
> +				? 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("%s: rpmh_write_async(%s, state=%d) failed (%d)\n"

You're missing a , for this to compile.

> +			       __func__, c->res_name, RPMH_WAKE_ONLY_STATE,
> +				 ret);
> +			return ret;
> +		}
> +	}
> +
> +	if (has_state_changed(c, RPMH_ACTIVE_ONLY_STATE)) {
> +		cmd.data = (c->aggr_state & BIT(RPMH_ACTIVE_ONLY_STATE))
> +				? c->res_on_val : c->res_off_val;
> +		ret = rpmh_write(c->rpmh_client, RPMH_ACTIVE_ONLY_STATE,
> +				 &cmd, 1);
> +		if (ret) {
> +			pr_err("%s: rpmh_write(%s, state=%d) failed (%d)\n",
> +			       __func__, c->res_name, RPMH_ACTIVE_ONLY_STATE,
> +				 ret);
> +			return ret;
> +		}
> +	}

But, RPMH_SLEEP_STATE, RPMH_WAKE_ONLY_STATE and RPMH_ACTIVE_ONLY_STATE
are values in an enum, so you could roll these up in a for loop and
reduce the duplication.

> +
> +	c->last_sent_aggr_state = c->aggr_state;
> +	c->peer->last_sent_aggr_state =  c->last_sent_aggr_state;
> +
> +	return 0;
> +}
> +
> +static int clk_rpmh_aggregate_state_send_command(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;
> +
> +	ret = clk_rpmh_send_aggregate_command(c);

"ret" doesn't exist.

> +	if (ret && enable)
> +		c->state = 0;
> +	else if (ret) {

If you have any part of your conditional wrapped in braces do wrap all
the others too.

> +		c->state = c->valid_state_mask;
> +		WARN(1, "clk: %s failed to disable\n", c->res_name);
> +	}
> +
> +	return ret;
> +}
> +
> +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;
> +
> +	ret = clk_rpmh_aggregate_state_send_command(c, true);
> +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);
> +
> +	mutex_lock(&rpmh_clk_lock);
> +
> +	if (!c->state)
> +		goto out;
> +
> +	clk_rpmh_aggregate_state_send_command(c, false);
> +out:
> +	mutex_unlock(&rpmh_clk_lock);
> +	return;
> +};
> +
> +static unsigned long clk_rpmh_recalc_rate(struct clk_hw *hw,
> +					  unsigned long parent_rate)
> +{
> +	struct clk_rpmh *r = to_clk_rpmh(hw);
> +
> +	/*
> +	 * RPMh clocks have a fixed rate. Return static rate set
> +	 * at init time.
> +	 */
> +	return r->rate;
> +}
> +
> +static const struct clk_ops clk_rpmh_ops = {
> +	.prepare	= clk_rpmh_prepare,
> +	.unprepare	= clk_rpmh_unprepare,
> +	.recalc_rate	= clk_rpmh_recalc_rate,
> +};
> +
> +/* Resource name must match resource id present in cmd-db. */
> +DEFINE_CLK_RPMH_ARC(sdm845, bi_tcxo, bi_tcxo_ao, "xo.lvl", 0x3, 0x0,
> +		    19200000, CLK_RPMH_APPS_RSC_STATE_MASK,
> +		    CLK_RPMH_APPS_RSC_AO_STATE_MASK);
> +DEFINE_CLK_RPMH_VRM(sdm845, ln_bb_clk2, ln_bb_clk2_ao, "lnbclka2",
> +		    19200000, CLK_RPMH_APPS_RSC_STATE_MASK,
> +		    CLK_RPMH_APPS_RSC_AO_STATE_MASK);
> +DEFINE_CLK_RPMH_VRM(sdm845, ln_bb_clk3, ln_bb_clk3_ao, "lnbclka3",
> +		    19200000, CLK_RPMH_APPS_RSC_STATE_MASK,
> +		    CLK_RPMH_APPS_RSC_AO_STATE_MASK);
> +DEFINE_CLK_RPMH_VRM(sdm845, rf_clk1, rf_clk1_ao, "rfclka1",
> +		    38400000, CLK_RPMH_APPS_RSC_STATE_MASK,
> +		    CLK_RPMH_APPS_RSC_AO_STATE_MASK);
> +DEFINE_CLK_RPMH_VRM(sdm845, rf_clk2, rf_clk2_ao, "rfclka2",
> +		    38400000, CLK_RPMH_APPS_RSC_STATE_MASK,
> +		    CLK_RPMH_APPS_RSC_AO_STATE_MASK);
> +DEFINE_CLK_RPMH_VRM(sdm845, rf_clk3, rf_clk3_ao, "rfclka3",
> +		    38400000, CLK_RPMH_APPS_RSC_STATE_MASK,
> +		    CLK_RPMH_APPS_RSC_AO_STATE_MASK);
> +
> +static struct clk_hw *sdm845_rpmh_clocks[] = {
> +	[RPMH_CXO_CLK]		= &sdm845_bi_tcxo.hw,
> +	[RPMH_CXO_CLK_A]	= &sdm845_bi_tcxo_ao.hw,

Registering these fails with EEXIST because the gcc driver also register
them.

> +	[RPMH_LN_BB_CLK2]	= &sdm845_ln_bb_clk2.hw,
> +	[RPMH_LN_BB_CLK2_A]	= &sdm845_ln_bb_clk2_ao.hw,
> +	[RPMH_LN_BB_CLK3]	= &sdm845_ln_bb_clk3.hw,
> +	[RPMH_LN_BB_CLK3_A]	= &sdm845_ln_bb_clk3_ao.hw,
> +	[RPMH_RF_CLK1]		= &sdm845_rf_clk1.hw,
> +	[RPMH_RF_CLK1_A]	= &sdm845_rf_clk1_ao.hw,
> +	[RPMH_RF_CLK2]		= &sdm845_rf_clk2.hw,
> +	[RPMH_RF_CLK2_A]	= &sdm845_rf_clk2_ao.hw,
> +	[RPMH_RF_CLK3]		= &sdm845_rf_clk3.hw,
> +	[RPMH_RF_CLK3_A]	= &sdm845_rf_clk3_ao.hw,
> +};
> +
> +static const struct clk_rpmh_desc clk_rpmh_sdm845 = {
> +	.clks = sdm845_rpmh_clocks,
> +	.num_clks = ARRAY_SIZE(sdm845_rpmh_clocks),
> +};
> +
> +static const struct of_device_id clk_rpmh_match_table[] = {
> +	{ .compatible = "qcom,rpmh-clk-sdm845", .data = &clk_rpmh_sdm845},
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, clk_rpmh_match_table);

Please move the match_table just prior to the definition of your
platform_driver.

> +
> +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;

prop is unused.

> +	struct rpmh_client *rpmh_client = NULL;

Don't goto err until you have acquired rpmh_client and you don't need to
initialize this variable.

> +
> +	desc = of_device_get_match_data(&pdev->dev);
> +	if (!desc) {
> +		ret = -EINVAL;
> +		goto err;
> +	}

This won't happen, no need to check for it.

> +
> +	ret = cmd_db_ready();
> +	if (ret) {
> +		if (ret != -EPROBE_DEFER) {
> +			dev_err(&pdev->dev, "Command DB not available (%d)\n",
> +				ret);
> +			goto err;

goto err? There's nothing to clean up at this point.

> +		}
> +		return ret;
> +	}
> +
> +	rpmh_client = rpmh_get_client(pdev);
> +	if (IS_ERR(rpmh_client)) {
> +		ret = PTR_ERR(rpmh_client);
> +		if (ret != -EPROBE_DEFER)

You're getting a handle to your parent, it's not going to return
-EPROBE_DEFER.

> +			dev_err(&pdev->dev, "failed to request RPMh client, ret=%d\n",
> +				ret);
> +		return ret;
> +	}
> +
> +	hw_clks = desc->clks;
> +	num_clks = desc->num_clks;
> +
> +	rcc = devm_kzalloc(&pdev->dev, sizeof(*rcc) + sizeof(*clks) * num_clks,
> +			   GFP_KERNEL);
> +	if (!rcc) {
> +		ret = -ENOMEM;
> +		goto err;
> +	}
> +
> +	clks = rcc->clks;
> +	data = &rcc->data;
> +	data->clks = clks;
> +	data->clk_num = num_clks;
> +
> +	for (i = 0; i < num_clks; i++) {
> +		rpmh_clk = to_clk_rpmh(hw_clks[i]);
> +		rpmh_clk->res_addr = cmd_db_read_addr(rpmh_clk->res_name);
> +		if (!rpmh_clk->res_addr) {
> +			dev_err(&pdev->dev, "missing RPMh resource address for %s\n",
> +				rpmh_clk->res_name);
> +			ret = -ENODEV;
> +			goto err;
> +		}
> +
> +		rpmh_clk->rpmh_client = rpmh_client;
> +
> +		clk = devm_clk_register(&pdev->dev, hw_clks[i]);
> +		if (IS_ERR(clk)) {

Please add:

dev_err(&pdev->dev, "failed to register %s\n", hw_clks[i]->init->name);

> +			ret = PTR_ERR(clk);
> +			goto err;
> +		}
> +
> +		clks[i] = clk;
> +	}
> +
> +	ret = of_clk_add_provider(pdev->dev.of_node, of_clk_src_onecell_get,
> +				  data);
> +	if (ret)

Please add:

dev_err(&pdev->dev, "failed to add clock provider\n");

> +		goto err;
> +
> +	dev_info(&pdev->dev, "Registered RPMh clocks\n");

Please don't spam the kernel log.

> +	return ret;

ret can't be anything but 0 here, so let's make it easer to read by
writing 0 here.

> +
> +err:
> +	if (rpmh_client)
> +		rpmh_release(rpmh_client);

This is annoying (but not your fault).

> +
> +	dev_err(&pdev->dev, "Error registering RPMh Clock driver (%d)\n", ret);

Testing the driver I got this error message, it didn't help! Had to add
the two dev_err above, just drop this one.

> +	return ret;
> +}
> +
> +static struct platform_driver clk_rpmh_driver = {
> +	.probe		= clk_rpmh_probe,

Your driver is tristate and works just fine as a kernel module, so you
need a remove function to call rpmh_release(rpmh_client) - or we need to
get rid of the need to call that.

> +	.driver		= {
> +		.name	= "clk-rpmh",
> +		.of_match_table = clk_rpmh_match_table,
> +	},
> +};
> +
> +static int __init clk_rpmh_init(void)
> +{
> +	return platform_driver_register(&clk_rpmh_driver);
> +}
> +subsys_initcall(clk_rpmh_init);
> +
> +static void __exit clk_rpmh_exit(void)
> +{
> +	platform_driver_unregister(&clk_rpmh_driver);
> +}
> +module_exit(clk_rpmh_exit);
> +
> +MODULE_DESCRIPTION("QTI RPMh Clock Driver");

We use "Qualcomm" or "QCOM" in all existing driver, can you please use
that here too?

> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:clk-rpmh");

Nothing is going to attempt to autoload a driver based on the alias
platform:clk-rpmh, so just drop this.

Regards,
Bjorn