Message-ID: <YSO5Njg3DXo64InF@ripper>
Date:   Mon, 23 Aug 2021 08:05:26 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Thara Gopinath <thara.gopinath@...aro.org>, agross@...nel.org,
        rui.zhang@...el.com, viresh.kumar@...aro.org, rjw@...ysocki.net,
        robh+dt@...nel.org, steev@...i.org, tdas@...eaurora.org,
        mka@...omium.org, linux-arm-msm@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [Patch v5 2/6] thermal: qcom: Add support for LMh driver

On Sat 21 Aug 02:41 PDT 2021, Daniel Lezcano wrote:

> 
> Hi Thara,
> 
> On 09/08/2021 21:16, Thara Gopinath wrote:
> > Driver enabling various pieces of Limits Management Hardware(LMh) for cpu
> > cluster0 and cpu cluster1 namely kick starting monitoring of temperature,
> > current, battery current violations, enabling reliability algorithm and
> > setting up various temperature limits.
> > 
> > The following has been explained in the cover letter. I am including this
> > here so that this remains in the commit message as well.
> > 
> > LMh is a hardware infrastructure on some Qualcomm SoCs that can enforce
> > temperature and current limits as programmed by software for certain IPs
> > like CPU. On many newer LMh is configured by firmware/TZ and no programming
> > is needed from the kernel side. But on certain SoCs like sdm845 the
> > firmware does not do a complete programming of the h/w. On such soc's
> > kernel software has to explicitly set up the temperature limits and turn on
> > various monitoring and enforcing algorithms on the hardware.
> > 
> > Tested-by: Steev Klimaszewski <steev@...i.org> # Lenovo Yoga C630
> > Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>
> 
> Is it possible to have an option to disable/enable the LMh driver at
> runtime, for instance with a module parameter ?
> 

Are you referring to being able to disable the hardware throttling, or
the driver's changes to thermal pressure?

I'm not aware of any way to disable the hardware. I do remember that
there was some experiments done (with a hacked up boot chain) early on
and iirc it was concluded that it's not a good idea.


Either way, if there is a way and there is a use for it, we can always
add such parameter incrementally. So I suggest that we merge this as is.

Regards,
Bjorn

> > ---
> > 
> > v4->v5:
> > 	- Minor change related to renaming of dt binding property qcom,lmh-cpu
> > 	  to cpus as per Rob Herring's review comments.
> > 
> > v3->v4:
> > 	- Minor code re-arrangement and removal of redundant code as per Bjorn's
> > 	  review comments
> > 	- Added suppress_bind_attrs to driver as per Bjorn's review comments.
> > 	- Changes to support changes in LMh dt node properties naming and types.
> > 
> > v2->v3:
> > 	- Rearranged enabling of various LMh subfunction and removed returning
> > 	  on error in enabling any one subfunction as the different pieces can
> > 	  operate and thus be enabled independently.
> > 	- Other minor cosmetic fixes.
> > 
> > v1->v2:
> > 	- Cosmetic and spelling fixes from review comments from Randy Dunlap
> > 	- Added irq_disable to lmh_irq_ops and removed disabling of irq from
> > 	  lmh_handle_irq. Now cpufreq explicitly disables irq prior to
> > 	  handling it as per Bjorn's suggestion.
> > 	- Rebased to new version of qcom_scm_lmh_dcvsh as changed in patch 1.
> > 	- Removed generic dt compatible string and introduced platform specific one
> > 	  as per Bjorn's suggestion.
> > 	- Take arm, low and high temp thresholds for LMh from dt properties instead of
> > 	  #defines in the driver as per Daniel's suggestion.
> > 	- Other minor fixes.
> > 
> >  drivers/thermal/qcom/Kconfig  |  10 ++
> >  drivers/thermal/qcom/Makefile |   1 +
> >  drivers/thermal/qcom/lmh.c    | 232 ++++++++++++++++++++++++++++++++++
> >  3 files changed, 243 insertions(+)
> >  create mode 100644 drivers/thermal/qcom/lmh.c
> > 
> > diff --git a/drivers/thermal/qcom/Kconfig b/drivers/thermal/qcom/Kconfig
> > index 8d5ac2df26dc..7d942f71e532 100644
> > --- a/drivers/thermal/qcom/Kconfig
> > +++ b/drivers/thermal/qcom/Kconfig
> > @@ -31,3 +31,13 @@ config QCOM_SPMI_TEMP_ALARM
> >  	  trip points. The temperature reported by the thermal sensor reflects the
> >  	  real time die temperature if an ADC is present or an estimate of the
> >  	  temperature based upon the over temperature stage value.
> > +
> > +config QCOM_LMH
> > +	tristate "Qualcomm Limits Management Hardware"
> > +	depends on ARCH_QCOM
> > +	help
> > +	  This enables initialization of Qualcomm limits management
> > +	  hardware(LMh). LMh allows for hardware-enforced mitigation for cpus based on
> > +	  input from temperature and current sensors.  On many newer Qualcomm SoCs
> > +	  LMh is configured in the firmware and this feature need not be enabled.
> > +	  However, on certain SoCs like sdm845 LMh has to be configured from kernel.
> > diff --git a/drivers/thermal/qcom/Makefile b/drivers/thermal/qcom/Makefile
> > index 252ea7d9da0b..0fa2512042e7 100644
> > --- a/drivers/thermal/qcom/Makefile
> > +++ b/drivers/thermal/qcom/Makefile
> > @@ -5,3 +5,4 @@ qcom_tsens-y			+= tsens.o tsens-v2.o tsens-v1.o tsens-v0_1.o \
> >  				   tsens-8960.o
> >  obj-$(CONFIG_QCOM_SPMI_ADC_TM5)	+= qcom-spmi-adc-tm5.o
> >  obj-$(CONFIG_QCOM_SPMI_TEMP_ALARM)	+= qcom-spmi-temp-alarm.o
> > +obj-$(CONFIG_QCOM_LMH)		+= lmh.o
> > diff --git a/drivers/thermal/qcom/lmh.c b/drivers/thermal/qcom/lmh.c
> > new file mode 100644
> > index 000000000000..eafa7526eb8b
> > --- /dev/null
> > +++ b/drivers/thermal/qcom/lmh.c
> > @@ -0,0 +1,232 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +/*
> > + * Copyright (C) 2021, Linaro Limited. All rights reserved.
> > + */
> > +#include <linux/module.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/err.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/slab.h>
> > +#include <linux/qcom_scm.h>
> > +
> > +#define LMH_NODE_DCVS			0x44435653
> > +#define LMH_CLUSTER0_NODE_ID		0x6370302D
> > +#define LMH_CLUSTER1_NODE_ID		0x6370312D
> > +
> > +#define LMH_SUB_FN_THERMAL		0x54484D4C
> > +#define LMH_SUB_FN_CRNT			0x43524E54
> > +#define LMH_SUB_FN_REL			0x52454C00
> > +#define LMH_SUB_FN_BCL			0x42434C00
> > +
> > +#define LMH_ALGO_MODE_ENABLE		0x454E424C
> > +#define LMH_TH_HI_THRESHOLD		0x48494748
> > +#define LMH_TH_LOW_THRESHOLD		0x4C4F5700
> > +#define LMH_TH_ARM_THRESHOLD		0x41524D00
> > +
> > +#define LMH_REG_DCVS_INTR_CLR		0x8
> > +
> > +struct lmh_hw_data {
> > +	void __iomem *base;
> > +	struct irq_domain *domain;
> > +	int irq;
> > +};
> > +
> > +static irqreturn_t lmh_handle_irq(int hw_irq, void *data)
> > +{
> > +	struct lmh_hw_data *lmh_data = data;
> > +	int irq = irq_find_mapping(lmh_data->domain, 0);
> > +
> > +	/* Call the cpufreq driver to handle the interrupt */
> > +	if (irq)
> > +		generic_handle_irq(irq);
> > +
> > +	return 0;
> > +}
> > +
> > +static void lmh_enable_interrupt(struct irq_data *d)
> > +{
> > +	struct lmh_hw_data *lmh_data = irq_data_get_irq_chip_data(d);
> > +
> > +	/* Clear the existing interrupt */
> > +	writel(0xff, lmh_data->base + LMH_REG_DCVS_INTR_CLR);
> > +	enable_irq(lmh_data->irq);
> > +}
> > +
> > +static void lmh_disable_interrupt(struct irq_data *d)
> > +{
> > +	struct lmh_hw_data *lmh_data = irq_data_get_irq_chip_data(d);
> > +
> > +	disable_irq_nosync(lmh_data->irq);
> > +}
> > +
> > +static struct irq_chip lmh_irq_chip = {
> > +	.name           = "lmh",
> > +	.irq_enable	= lmh_enable_interrupt,
> > +	.irq_disable	= lmh_disable_interrupt
> > +};
> > +
> > +static int lmh_irq_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
> > +{
> > +	struct lmh_hw_data *lmh_data = d->host_data;
> > +
> > +	irq_set_chip_and_handler(irq, &lmh_irq_chip, handle_simple_irq);
> > +	irq_set_chip_data(irq, lmh_data);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct irq_domain_ops lmh_irq_ops = {
> > +	.map = lmh_irq_map,
> > +	.xlate = irq_domain_xlate_onecell,
> > +};
> > +
> > +static int lmh_probe(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct device_node *np = dev->of_node;
> > +	struct device_node *cpu_node;
> > +	struct lmh_hw_data *lmh_data;
> > +	int temp_low, temp_high, temp_arm, cpu_id, ret;
> > +	u32 node_id;
> > +
> > +	lmh_data = devm_kzalloc(dev, sizeof(*lmh_data), GFP_KERNEL);
> > +	if (!lmh_data)
> > +		return -ENOMEM;
> > +
> > +	lmh_data->base = devm_platform_ioremap_resource(pdev, 0);
> > +	if (IS_ERR(lmh_data->base))
> > +		return PTR_ERR(lmh_data->base);
> > +
> > +	cpu_node = of_parse_phandle(np, "cpus", 0);
> > +	if (!cpu_node)
> > +		return -EINVAL;
> > +	cpu_id = of_cpu_node_to_id(cpu_node);
> > +	of_node_put(cpu_node);
> > +
> > +	ret = of_property_read_u32(np, "qcom,lmh-temp-high-millicelsius", &temp_high);
> > +	if (ret) {
> > +		dev_err(dev, "missing qcom,lmh-temp-high-millicelsius property\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = of_property_read_u32(np, "qcom,lmh-temp-low-millicelsius", &temp_low);
> > +	if (ret) {
> > +		dev_err(dev, "missing qcom,lmh-temp-low-millicelsius property\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = of_property_read_u32(np, "qcom,lmh-temp-arm-millicelsius", &temp_arm);
> > +	if (ret) {
> > +		dev_err(dev, "missing qcom,lmh-temp-arm-millicelsius property\n");
> > +		return ret;
> > +	}
> > +
> > +	/*
> > +	 * Only sdm845 has lmh hardware currently enabled from hlos. If this is needed
> > +	 * for other platforms, revisit this to check if the <cpu-id, node-id> should be part
> > +	 * of a dt match table.
> > +	 */
> > +	if (cpu_id == 0) {
> > +		node_id = LMH_CLUSTER0_NODE_ID;
> > +	} else if (cpu_id == 4) {
> > +		node_id = LMH_CLUSTER1_NODE_ID;
> > +	} else {
> > +		dev_err(dev, "Wrong CPU id associated with LMh node\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (!qcom_scm_lmh_dcvsh_available())
> > +		return -EINVAL;
> > +
> > +	ret = qcom_scm_lmh_dcvsh(LMH_SUB_FN_CRNT, LMH_ALGO_MODE_ENABLE, 1,
> > +				 LMH_NODE_DCVS, node_id, 0);
> > +	if (ret)
> > +		dev_err(dev, "Error %d enabling current subfunction\n", ret);
> > +
> > +	ret = qcom_scm_lmh_dcvsh(LMH_SUB_FN_REL, LMH_ALGO_MODE_ENABLE, 1,
> > +				 LMH_NODE_DCVS, node_id, 0);
> > +	if (ret)
> > +		dev_err(dev, "Error %d enabling reliability subfunction\n", ret);
> > +
> > +	ret = qcom_scm_lmh_dcvsh(LMH_SUB_FN_BCL, LMH_ALGO_MODE_ENABLE, 1,
> > +				 LMH_NODE_DCVS, node_id, 0);
> > +	if (ret)
> > +		dev_err(dev, "Error %d enabling BCL subfunction\n", ret);
> > +
> > +	ret = qcom_scm_lmh_dcvsh(LMH_SUB_FN_THERMAL, LMH_ALGO_MODE_ENABLE, 1,
> > +				 LMH_NODE_DCVS, node_id, 0);
> > +	if (ret) {
> > +		dev_err(dev, "Error %d enabling thermal subfunction\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	ret = qcom_scm_lmh_profile_change(0x1);
> > +	if (ret) {
> > +		dev_err(dev, "Error %d changing profile\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	/* Set default thermal trips */
> > +	ret = qcom_scm_lmh_dcvsh(LMH_SUB_FN_THERMAL, LMH_TH_ARM_THRESHOLD, temp_arm,
> > +				 LMH_NODE_DCVS, node_id, 0);
> > +	if (ret) {
> > +		dev_err(dev, "Error setting thermal ARM threshold%d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	ret = qcom_scm_lmh_dcvsh(LMH_SUB_FN_THERMAL, LMH_TH_HI_THRESHOLD, temp_high,
> > +				 LMH_NODE_DCVS, node_id, 0);
> > +	if (ret) {
> > +		dev_err(dev, "Error setting thermal HI threshold%d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	ret = qcom_scm_lmh_dcvsh(LMH_SUB_FN_THERMAL, LMH_TH_LOW_THRESHOLD, temp_low,
> > +				 LMH_NODE_DCVS, node_id, 0);
> > +	if (ret) {
> > +		dev_err(dev, "Error setting thermal ARM threshold%d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	lmh_data->irq = platform_get_irq(pdev, 0);
> > +	lmh_data->domain = irq_domain_add_linear(np, 1, &lmh_irq_ops, lmh_data);
> > +	if (!lmh_data->domain) {
> > +		dev_err(dev, "Error adding irq_domain\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	/* Disable the irq and let cpufreq enable it when ready to handle the interrupt */
> > +	irq_set_status_flags(lmh_data->irq, IRQ_NOAUTOEN);
> > +	ret = devm_request_irq(dev, lmh_data->irq, lmh_handle_irq,
> > +			       IRQF_ONESHOT | IRQF_NO_SUSPEND,
> > +			       "lmh-irq", lmh_data);
> > +	if (ret) {
> > +		dev_err(dev, "Error %d registering irq %x\n", ret, lmh_data->irq);
> > +		irq_domain_remove(lmh_data->domain);
> > +		return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id lmh_table[] = {
> > +	{ .compatible = "qcom,sdm845-lmh", },
> > +	{}
> > +};
> > +MODULE_DEVICE_TABLE(of, lmh_table);
> > +
> > +static struct platform_driver lmh_driver = {
> > +	.probe = lmh_probe,
> > +	.driver = {
> > +		.name = "qcom-lmh",
> > +		.of_match_table = lmh_table,
> > +		.suppress_bind_attrs = true,
> > +	},
> > +};
> > +module_platform_driver(lmh_driver);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_DESCRIPTION("QCOM LMh driver");
> > 
> 
> 
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