RE: [PATCH v6 3/3] drivers: soc: xilinx: Add ZynqMP PM driver

[Jolly Shah <JOLLYS@xilinx.com>]

Hi Sudeep,

> -----Original Message-----
> From: Sudeep Holla <sudeep.holla@arm.com>
> Sent: Wednesday, January 30, 2019 2:13 AM
> To: Jolly Shah <JOLLYS@xilinx.com>
> Cc: matthias.bgg@gmail.com; andy.gross@linaro.org; shawnguo@kernel.org;
> geert+renesas@glider.be; bjorn.andersson@linaro.org;
> sean.wang@mediatek.com; m.szyprowski@samsung.com; Michal Simek
> <michals@xilinx.com>; robh+dt@kernel.org; mark.rutland@arm.com; Rajan
> Vaja <RAJANV@xilinx.com>; devicetree@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; Sudeep Holla
> <sudeep.holla@arm.com>; Rajan Vaja <RAJANV@xilinx.com>; Jolly Shah
> <JOLLYS@xilinx.com>
> Subject: Re: [PATCH v6 3/3] drivers: soc: xilinx: Add ZynqMP PM driver
> 
> On Tue, Jan 29, 2019 at 12:38:21PM -0800, Jolly Shah wrote:
> > From: Rajan Vaja <rajan.vaja@xilinx.com>
> >
> > Add ZynqMP PM driver. PM driver provides power management
> > support for ZynqMP.
> >
> > Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
> > Signed-off-by: Jolly Shah <jollys@xilinx.com>
> > ---
> >  drivers/soc/xilinx/Kconfig        |  11 +++
> >  drivers/soc/xilinx/Makefile       |   1 +
> >  drivers/soc/xilinx/zynqmp_power.c | 178
> ++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 190 insertions(+)
> >  create mode 100644 drivers/soc/xilinx/zynqmp_power.c
> >
> > diff --git a/drivers/soc/xilinx/Kconfig b/drivers/soc/xilinx/Kconfig
> > index 687c8f3..5025e0e 100644
> > --- a/drivers/soc/xilinx/Kconfig
> > +++ b/drivers/soc/xilinx/Kconfig
> > @@ -17,4 +17,15 @@ config XILINX_VCU
> >  	  To compile this driver as a module, choose M here: the
> >  	  module will be called xlnx_vcu.
> >
> > +config ZYNQMP_POWER
> > +	bool "Enable Xilinx Zynq MPSoC Power Management driver"
> > +	depends on PM && ARCH_ZYNQMP
> > +	default y
> > +	help
> > +	  Say yes to enable power management support for ZyqnMP SoC.
> > +	  This driver uses firmware driver as an interface for power
> > +	  management request to firmware. It registers isr to handle
> > +	  power management callbacks from firmware.
> > +	  If in doubt, say N.
> > +
> >  endmenu
> > diff --git a/drivers/soc/xilinx/Makefile b/drivers/soc/xilinx/Makefile
> > index dee8fd5..428b9db 100644
> > --- a/drivers/soc/xilinx/Makefile
> > +++ b/drivers/soc/xilinx/Makefile
> > @@ -1,2 +1,3 @@
> >  # SPDX-License-Identifier: GPL-2.0
> >  obj-$(CONFIG_XILINX_VCU)	+= xlnx_vcu.o
> > +obj-$(CONFIG_ZYNQMP_POWER)	+= zynqmp_power.o
> > diff --git a/drivers/soc/xilinx/zynqmp_power.c
> b/drivers/soc/xilinx/zynqmp_power.c
> > new file mode 100644
> > index 0000000..771cb59
> > --- /dev/null
> > +++ b/drivers/soc/xilinx/zynqmp_power.c
> > @@ -0,0 +1,178 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Xilinx Zynq MPSoC Power Management
> > + *
> > + *  Copyright (C) 2014-2018 Xilinx, Inc.
> > + *
> > + *  Davorin Mista <davorin.mista@aggios.com>
> > + *  Jolly Shah <jollys@xilinx.com>
> > + *  Rajan Vaja <rajan.vaja@xilinx.com>
> > + */
> > +
> > +#include <linux/mailbox_client.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reboot.h>
> > +#include <linux/suspend.h>
> > +
> > +#include <linux/firmware/xlnx-zynqmp.h>
> > +
> > +enum pm_suspend_mode {
> > +	PM_SUSPEND_MODE_FIRST = 0,
> > +	PM_SUSPEND_MODE_STD = PM_SUSPEND_MODE_FIRST,
> > +	PM_SUSPEND_MODE_POWER_OFF,
> > +};
> > +
> > +#define PM_SUSPEND_MODE_FIRST	PM_SUSPEND_MODE_STD
> > +
> > +static const char *const suspend_modes[] = {
> > +	[PM_SUSPEND_MODE_STD] = "standard",
> > +	[PM_SUSPEND_MODE_POWER_OFF] = "power-off",
> > +};
> > +
> > +static enum pm_suspend_mode suspend_mode = PM_SUSPEND_MODE_STD;
> > +
> > +enum pm_api_cb_id {
> > +	PM_INIT_SUSPEND_CB = 30,
> > +	PM_ACKNOWLEDGE_CB,
> > +	PM_NOTIFY_CB,
> > +};
> > +
> > +static void zynqmp_pm_get_callback_data(u32 *buf)
> > +{
> > +	zynqmp_pm_invoke_fn(GET_CALLBACK_DATA, 0, 0, 0, 0, buf);
> > +}
> > +
> > +static irqreturn_t zynqmp_pm_isr(int irq, void *data)
> > +{
> > +	u32 payload[CB_PAYLOAD_SIZE];
> > +
> > +	zynqmp_pm_get_callback_data(payload);
> > +
> > +	/* First element is callback API ID, others are callback arguments */
> > +	if (payload[0] == PM_INIT_SUSPEND_CB) {
> > +		switch (payload[1]) {
> > +		case SUSPEND_SYSTEM_SHUTDOWN:
> > +			orderly_poweroff(true);
> > +			break;
> > +		case SUSPEND_POWER_REQUEST:
> > +			pm_suspend(PM_SUSPEND_MEM);
> > +			break;
> > +		default:
> > +			pr_err("%s Unsupported InitSuspendCb reason "
> > +				"code %d\n", __func__, payload[1]);
> > +		}
> > +	}
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static ssize_t suspend_mode_show(struct device *dev,
> > +				 struct device_attribute *attr, char *buf)
> > +{
> > +	char *s = buf;
> > +	int md;
> > +
> > +	for (md = PM_SUSPEND_MODE_FIRST; md <
> ARRAY_SIZE(suspend_modes); md++)
> > +		if (suspend_modes[md]) {
> > +			if (md == suspend_mode)
> > +				s += sprintf(s, "[%s] ", suspend_modes[md]);
> > +			else
> > +				s += sprintf(s, "%s ", suspend_modes[md]);
> > +		}
> > +
> > +	/* Convert last space to newline */
> > +	if (s != buf)
> > +		*(s - 1) = '\n';
> > +	return (s - buf);
> > +}
> > +
> > +static ssize_t suspend_mode_store(struct device *dev,
> > +				  struct device_attribute *attr,
> > +				  const char *buf, size_t count)
> > +{
> > +	int md, ret = -EINVAL;
> > +	const struct zynqmp_eemi_ops *eemi_ops =
> zynqmp_pm_get_eemi_ops();
> > +
> > +	if (!eemi_ops || !eemi_ops->set_suspend_mode)
> > +		return ret;
> > +
> > +	for (md = PM_SUSPEND_MODE_FIRST; md <
> ARRAY_SIZE(suspend_modes); md++)
> > +		if (suspend_modes[md] &&
> > +		    sysfs_streq(suspend_modes[md], buf)) {
> > +			ret = 0;
> > +			break;
> > +		}
> > +
> > +	if (!ret && md != suspend_mode) {
> > +		ret = eemi_ops->set_suspend_mode(md);
> > +		if (likely(!ret))
> > +			suspend_mode = md;
> > +	}
> > +
> > +	return ret ? ret : count;
> > +}
> > +
> > +static DEVICE_ATTR_RW(suspend_mode);
> > +
> > +static int zynqmp_pm_probe(struct platform_device *pdev)
> > +{
> > +	int ret, irq;
> > +	u32 pm_api_version;
> > +
> > +	const struct zynqmp_eemi_ops *eemi_ops =
> zynqmp_pm_get_eemi_ops();
> > +
> > +	if (!eemi_ops || !eemi_ops->get_api_version || !eemi_ops-
> >init_finalize)
> > +		return -ENXIO;
> > +
> > +	eemi_ops->init_finalize();
> > +	eemi_ops->get_api_version(&pm_api_version);
> > +
> > +	/* Check PM API version number */
> > +	if (pm_api_version < ZYNQMP_PM_VERSION)
> > +		return -ENODEV;
> > +
> > +	irq = platform_get_irq(pdev, 0);
> > +	if (irq <= 0)
> > +		return -ENXIO;
> > +
> > +	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
> zynqmp_pm_isr,
> > +					IRQF_NO_SUSPEND | IRQF_ONESHOT,
> > +					dev_name(&pdev->dev), &pdev->dev);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "devm_request_threaded_irq '%d' failed "
> > +			"with %d\n", irq, ret);
> > +		return ret;
> > +	}
> > +
> > +	ret = sysfs_create_file(&pdev->dev.kobj,
> &dev_attr_suspend_mode.attr);
> 
> NACK, if this is for system suspend/reset ? You can just use exiting
> sysfs, no need to create Xilinx specific new ones. Moreover you need to
> use PSCI to make sure higher ELs can do orderly suspend/shutdown.
> 

We have power off suspend mode which is not supported by existing sysfs and hence new one is needed. 
Suspend is handled through PSCI interface only.

Thanks,
Jolly Shah

> --
> Regards,
> Sudeep