RE: [PATCH V6 2/4] firmware: imx: enable imx scu general irq function

[Anson Huang <anson.huang@nxp.com>]

Best Regards!
Anson Huang

> -----Original Message-----
> From: Aisheng Dong
> Sent: 2019年4月9日 11:21
> To: Anson Huang <anson.huang@nxp.com>; robh+dt@kernel.org;
> mark.rutland@arm.com; shawnguo@kernel.org; s.hauer@pengutronix.de;
> kernel@pengutronix.de; festevam@gmail.com; a.zummo@towertech.it;
> alexandre.belloni@bootlin.com; ulf.hansson@linaro.org; sboyd@kernel.org;
> Peng Fan <peng.fan@nxp.com>; Daniel Baluta <daniel.baluta@nxp.com>;
> devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-rtc@vger.kernel.org
> Cc: dl-linux-imx <linux-imx@nxp.com>
> Subject: RE: [PATCH V6 2/4] firmware: imx: enable imx scu general irq
> function
> 
> > From: Anson Huang
> > Sent: Tuesday, April 9, 2019 10:43 AM
> > Subject: [PATCH V6 2/4] firmware: imx: enable imx scu general irq
> > function
> >
> > The System Controller Firmware (SCFW) controls RTC, thermal and WDOG
> > etc., these resources' interrupt function are managed by SCU. When any
> > IRQ pending, SCU will notify Linux via MU general interrupt channel
> > #3, and Linux kernel needs to call SCU APIs to get IRQ status and
> > notify each module to handle the interrupt.
> >
> > Since there is no data transmission for SCU IRQ notification, so
> > doorbell mode is used for this MU channel, and SCU driver will use
> > notifier mechanism to broadcast to every module which registers the SCU
> block notifier.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> > ---
> > Changes since V5:
> > 	- use ATOMIC_NOTIFIER instead of BLOCKING_NOTIFIER for irq
> > notification;
> > 	- add memory free for failed case to avoid memory leak;
> > 	- add new API imx_scu_irq_enable() for modules to enable/disable
> > their own irqs.
> > ---
> >  drivers/firmware/imx/Makefile      |   2 +-
> >  drivers/firmware/imx/imx-scu-irq.c | 166
> > +++++++++++++++++++++++++++++++++++++
> >  drivers/firmware/imx/imx-scu.c     |   6 ++
> >  include/linux/firmware/imx/sci.h   |   5 ++
> >  4 files changed, 178 insertions(+), 1 deletion(-)  create mode 100644
> > drivers/firmware/imx/imx-scu-irq.c
> >
> > diff --git a/drivers/firmware/imx/Makefile
> > b/drivers/firmware/imx/Makefile index 1b2e15b..802c4ad 100644
> > --- a/drivers/firmware/imx/Makefile
> > +++ b/drivers/firmware/imx/Makefile
> > @@ -1,3 +1,3 @@
> >  # SPDX-License-Identifier: GPL-2.0
> > -obj-$(CONFIG_IMX_SCU)		+= imx-scu.o misc.o
> > +obj-$(CONFIG_IMX_SCU)		+= imx-scu.o misc.o imx-scu-irq.o
> >  obj-$(CONFIG_IMX_SCU_PD)	+= scu-pd.o
> > diff --git a/drivers/firmware/imx/imx-scu-irq.c
> > b/drivers/firmware/imx/imx-scu-irq.c
> > new file mode 100644
> > index 0000000..4000c63
> > --- /dev/null
> > +++ b/drivers/firmware/imx/imx-scu-irq.c
> > @@ -0,0 +1,166 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright 2019 NXP
> > + *
> > + * Implementation of the SCU IRQ functions using MU.
> > + *
> > + */
> > +
> > +#include <dt-bindings/firmware/imx/rsrc.h> #include
> > +<linux/firmware/imx/ipc.h> #include <linux/mailbox_client.h>
> > +
> > +#define IMX_SC_IRQ_FUNC_ENABLE	1
> > +#define IMX_SC_IRQ_FUNC_STATUS	2
> > +#define IMX_SC_IRQ_NUM_GROUP	4
> > +
> > +static u32 mu_resource_id;
> > +
> > +struct imx_sc_msg_irq_get_status {
> > +	struct imx_sc_rpc_msg hdr;
> > +	union {
> > +		struct {
> > +			u16 resource;
> > +			u8 group;
> > +			u8 reserved;
> > +		} __packed req;
> > +		struct {
> > +			u32 status;
> > +		} resp;
> > +	} data;
> > +};
> > +
> > +struct imx_sc_msg_irq_enable {
> > +	struct imx_sc_rpc_msg hdr;
> > +	u32 mask;
> > +	u16 resource;
> > +	u8 group;
> > +	u8 enable;
> > +} __packed;
> > +
> > +static struct imx_sc_ipc *imx_sc_irq_ipc_handle; static struct
> > +work_struct imx_sc_irq_work; static
> > +ATOMIC_NOTIFIER_HEAD(imx_scu_irq_notifier_chain);
> > +
> > +int imx_scu_irq_register_notifier(struct notifier_block *nb) {
> > +	return atomic_notifier_chain_register(
> > +		&imx_scu_irq_notifier_chain, nb);
> > +}
> > +EXPORT_SYMBOL(imx_scu_irq_register_notifier);
> > +
> > +int imx_scu_irq_unregister_notifier(struct notifier_block *nb) {
> > +	return atomic_notifier_chain_unregister(
> > +		&imx_scu_irq_notifier_chain, nb);
> > +}
> > +EXPORT_SYMBOL(imx_scu_irq_unregister_notifier);
> > +
> > +static int imx_scu_irq_notifier_call_chain(unsigned long status, u8
> > +*group) {
> > +	return atomic_notifier_call_chain(&imx_scu_irq_notifier_chain,
> > +		status, (void *)group);
> > +}
> > +
> > +static void imx_scu_irq_work_handler(struct work_struct *work) {
> > +	struct imx_sc_msg_irq_get_status msg;
> > +	struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > +	u32 irq_status;
> > +	int ret;
> > +	u8 i;
> > +
> > +	for (i = 0; i < IMX_SC_IRQ_NUM_GROUP; i++) {
> > +		hdr->ver = IMX_SC_RPC_VERSION;
> > +		hdr->svc = IMX_SC_RPC_SVC_IRQ;
> > +		hdr->func = IMX_SC_IRQ_FUNC_STATUS;
> > +		hdr->size = 2;
> > +
> > +		msg.data.req.resource = mu_resource_id;
> > +		msg.data.req.group = i;
> > +
> > +		ret = imx_scu_call_rpc(imx_sc_irq_ipc_handle, &msg, true);
> > +		if (ret) {
> > +			pr_err("get irq group %d status failed, ret %d\n",
> > +			       i, ret);
> > +			return;
> > +		}
> > +
> > +		irq_status = msg.data.resp.status;
> > +		if (!irq_status)
> > +			continue;
> > +
> > +		imx_scu_irq_notifier_call_chain(irq_status, &i);
> > +	}
> > +}
> > +
> > +void imx_scu_irq_enable(u8 group, u32 mask, u8 enable) {
> 
> Why should this be a void return?
> 
> Besides that, a nitpick better rename to imx_scu_irq_group_enable to
> distinguish with the exist general irq enable.


Will add return value in V7 and rename it as well.

Anson.

> 
> Regards
> Dong Aisheng
> 
> > +	struct imx_sc_msg_irq_enable msg;
> > +	struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > +	int ret;
> > +
> > +	hdr->ver = IMX_SC_RPC_VERSION;
> > +	hdr->svc = IMX_SC_RPC_SVC_IRQ;
> > +	hdr->func = IMX_SC_IRQ_FUNC_ENABLE;
> > +	hdr->size = 3;
> > +
> > +	msg.resource = mu_resource_id;
> > +	msg.group = group;
> > +	msg.mask = mask;
> > +	msg.enable = enable;
> > +
> > +	ret = imx_scu_call_rpc(imx_sc_irq_ipc_handle, &msg, true);
> > +	if (ret)
> > +		pr_err("enable irq failed, group %d, mask %d, ret %d\n",
> > +			group, mask, ret);
> > +}
> > +EXPORT_SYMBOL(imx_scu_irq_enable);
> > +
> > +static void imx_scu_irq_callback(struct mbox_client *c, void *msg) {
> > +	schedule_work(&imx_sc_irq_work);
> > +}
> > +
> > +int imx_scu_enable_general_irq_channel(struct device *dev) {
> > +	struct of_phandle_args spec;
> > +	struct mbox_client *cl;
> > +	struct mbox_chan *ch;
> > +	int ret = 0, i = 0;
> > +
> > +	ret = imx_scu_get_handle(&imx_sc_irq_ipc_handle);
> > +	if (ret)
> > +		return ret;
> > +
> > +	cl = devm_kzalloc(dev, sizeof(*cl), GFP_KERNEL);
> > +	if (!cl)
> > +		return -ENOMEM;
> > +
> > +	cl->dev = dev;
> > +	cl->rx_callback = imx_scu_irq_callback;
> > +
> > +	/* SCU general IRQ uses general interrupt channel 3 */
> > +	ch = mbox_request_channel_byname(cl, "gip3");
> > +	if (IS_ERR(ch)) {
> > +		ret = PTR_ERR(ch);
> > +		dev_err(dev, "failed to request mbox chan gip3, ret %d\n",
> ret);
> > +		devm_kfree(dev, cl);
> > +		return ret;
> > +	}
> > +
> > +	INIT_WORK(&imx_sc_irq_work, imx_scu_irq_work_handler);
> > +
> > +	if (!of_parse_phandle_with_args(dev->of_node, "mboxes",
> > +				       "#mbox-cells", 0, &spec))
> > +		i = of_alias_get_id(spec.np, "mu");
> > +
> > +	/* use mu1 as general mu irq channel if failed */
> > +	if (i < 0)
> > +		i = 1;
> > +
> > +	mu_resource_id = IMX_SC_R_MU_0A + i;
> > +
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL(imx_scu_enable_general_irq_channel);
> > diff --git a/drivers/firmware/imx/imx-scu.c
> > b/drivers/firmware/imx/imx-scu.c index 2bb1a19..04a24a8 100644
> > --- a/drivers/firmware/imx/imx-scu.c
> > +++ b/drivers/firmware/imx/imx-scu.c
> > @@ -10,6 +10,7 @@
> >  #include <linux/err.h>
> >  #include <linux/firmware/imx/types.h>  #include
> > <linux/firmware/imx/ipc.h>
> > +#include <linux/firmware/imx/sci.h>
> >  #include <linux/interrupt.h>
> >  #include <linux/irq.h>
> >  #include <linux/kernel.h>
> > @@ -246,6 +247,11 @@ static int imx_scu_probe(struct platform_device
> > *pdev)
> >
> >  	imx_sc_ipc_handle = sc_ipc;
> >
> > +	ret = imx_scu_enable_general_irq_channel(dev);
> > +	if (ret)
> > +		dev_warn(dev,
> > +			"failed to enable general irq channel: %d\n", ret);
> > +
> >  	dev_info(dev, "NXP i.MX SCU Initialized\n");
> >
> >  	return devm_of_platform_populate(dev); diff --git
> > a/include/linux/firmware/imx/sci.h b/include/linux/firmware/imx/sci.h
> > index ebc5509..4100be7 100644
> > --- a/include/linux/firmware/imx/sci.h
> > +++ b/include/linux/firmware/imx/sci.h
> > @@ -15,4 +15,9 @@
> >
> >  #include <linux/firmware/imx/svc/misc.h>  #include
> > <linux/firmware/imx/svc/pm.h>
> > +
> > +int imx_scu_enable_general_irq_channel(struct device *dev); int
> > +imx_scu_irq_register_notifier(struct notifier_block *nb); int
> > +imx_scu_irq_unregister_notifier(struct notifier_block *nb); void
> > +imx_scu_irq_enable(u8 group, u32 mask, u8 enable);
> >  #endif /* _SC_SCI_H */
> > --
> > 2.7.4

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