Date:   Fri, 4 Nov 2016 14:46:40 +0000
From:   Ruxandra Ioana Radulescu <ruxandra.radulescu@....com>
To:     Stuart Yoder <stuart.yoder@....com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC:     German Rivera <german.rivera@....com>,
        "devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "agraf@...e.de" <agraf@...e.de>, "arnd@...db.de" <arnd@...db.de>,
        Leo Li <leoyang.li@....com>, Roy Pledge <roy.pledge@....com>,
        Haiying Wang <haiying.wang@....com>,
        Stuart Yoder <stuart.yoder@....com>
Subject: RE: [PATCH 7/9] bus: fsl-mc: dpio: add the DPAA2 DPIO service
 interface


> -----Original Message-----
> From: Stuart Yoder [mailto:stuart.yoder@....com]
> Sent: Friday, October 21, 2016 9:02 AM
> To: gregkh@...uxfoundation.org
> Cc: German Rivera <german.rivera@....com>; devel@...verdev.osuosl.org;
> linux-kernel@...r.kernel.org; agraf@...e.de; arnd@...db.de; Leo Li
> <leoyang.li@....com>; Roy Pledge <roy.pledge@....com>; Roy Pledge
> <roy.pledge@....com>; Haiying Wang <haiying.wang@....com>; Stuart
> Yoder <stuart.yoder@....com>
> Subject: [PATCH 7/9] bus: fsl-mc: dpio: add the DPAA2 DPIO service interface
> 
> From: Roy Pledge <Roy.Pledge@....com>
> 
> The DPIO service interface handles initialization of DPIO objects
> and exports APIs to be used by other DPAA2 object drivers to perform
> queuing and buffer management related operations.  The service allows
> registration of callbacks when frames or notifications are received.
> 
> Signed-off-by: Roy Pledge <roy.pledge@....com>
> Signed-off-by: Haiying Wang <haiying.wang@....com>
> Signed-off-by: Stuart Yoder <stuart.yoder@....com>
> ---
>  drivers/bus/fsl-mc/dpio/Makefile       |   2 +-
>  drivers/bus/fsl-mc/dpio/dpio-service.c | 614
> +++++++++++++++++++++++++++++++++
>  include/linux/fsl/dpaa2-io.h           | 138 ++++++++
>  3 files changed, 753 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/bus/fsl-mc/dpio/dpio-service.c
>  create mode 100644 include/linux/fsl/dpaa2-io.h
> 
> diff --git a/drivers/bus/fsl-mc/dpio/Makefile b/drivers/bus/fsl-
> mc/dpio/Makefile
> index 6588498..0778da7 100644
> --- a/drivers/bus/fsl-mc/dpio/Makefile
> +++ b/drivers/bus/fsl-mc/dpio/Makefile
> @@ -6,4 +6,4 @@ subdir-ccflags-y := -Werror
> 
>  obj-$(CONFIG_FSL_MC_DPIO) += fsl-mc-dpio.o
> 
> -fsl-mc-dpio-objs := dpio.o qbman-portal.o
> +fsl-mc-dpio-objs := dpio.o qbman-portal.o dpio-service.o
> diff --git a/drivers/bus/fsl-mc/dpio/dpio-service.c b/drivers/bus/fsl-
> mc/dpio/dpio-service.c
> new file mode 100644
> index 0000000..7a455a7
> --- /dev/null
> +++ b/drivers/bus/fsl-mc/dpio/dpio-service.c
> @@ -0,0 +1,614 @@
> +/*
> + * Copyright 2014-2016 Freescale Semiconductor Inc.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions are
> met:
> + *     * Redistributions of source code must retain the above copyright
> + *	 notice, this list of conditions and the following disclaimer.
> + *     * Redistributions in binary form must reproduce the above copyright
> + *	 notice, this list of conditions and the following disclaimer in the
> + *	 documentation and/or other materials provided with the
> distribution.
> + *     * Neither the name of Freescale Semiconductor nor the
> + *	 names of its contributors may be used to endorse or promote
> products
> + *	 derived from this software without specific prior written permission.
> + *
> + *
> + * ALTERNATIVELY, this software may be distributed under the terms of the
> + * GNU General Public License ("GPL") as published by the Free Software
> + * Foundation, either version 2 of that License or (at your option) any
> + * later version.
> + *
> + * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``AS IS'' AND
> ANY
> + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
> THE IMPLIED
> + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
> PURPOSE ARE
> + * DISCLAIMED. IN NO EVENT SHALL Freescale Semiconductor BE LIABLE FOR
> ANY
> + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> CONSEQUENTIAL DAMAGES
> + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
> GOODS OR SERVICES;
> + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> HOWEVER CAUSED AND
> + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
> OR TORT
> + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
> THE USE OF THIS
> + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +#include <linux/types.h>
> +#include <linux/fsl/mc.h>
> +#include <linux/fsl/dpaa2-io.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/interrupt.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/slab.h>
> +
> +#include "dpio.h"
> +#include "qbman-portal.h"
> +
> +struct dpaa2_io {
> +	atomic_t refs;
> +	struct dpaa2_io_desc dpio_desc;
> +	struct qbman_swp_desc swp_desc;
> +	struct qbman_swp *swp;
> +	struct list_head node;
> +	spinlock_t lock_mgmt_cmd;
> +	spinlock_t lock_notifications;
> +	struct list_head notifications;
> +};
> +
> +struct dpaa2_io_store {
> +	unsigned int max;
> +	dma_addr_t paddr;
> +	struct dpaa2_dq *vaddr;
> +	void *alloced_addr;    /* unaligned value from kmalloc() */
> +	unsigned int idx;      /* position of the next-to-be-returned entry */
> +	struct qbman_swp *swp; /* portal used to issue VDQCR */
> +	struct device *dev;    /* device used for DMA mapping */
> +};
> +
> +/* keep a per cpu array of DPIOs for fast access */
> +static struct dpaa2_io *dpio_by_cpu[NR_CPUS];
> +static struct list_head dpio_list = LIST_HEAD_INIT(dpio_list);
> +static DEFINE_SPINLOCK(dpio_list_lock);
> +
> +static inline struct dpaa2_io *service_select_by_cpu(struct dpaa2_io *d,
> +						     int cpu)
> +{
> +	if (d)
> +		return d;
> +
> +	if (unlikely(cpu >= NR_CPUS))
> +		return NULL;
> +
> +	/*
> +	 * If cpu == -1, choose the current cpu, with no guarantees about
> +	 * potentially being migrated away.
> +	 */
> +	if (unlikely(cpu < 0))
> +		cpu = smp_processor_id();
> +
> +	/* If a specific cpu was requested, pick it up immediately */
> +	return dpio_by_cpu[cpu];
> +}
> +
> +static inline struct dpaa2_io *service_select(struct dpaa2_io *d)
> +{
> +	if (d)
> +		return d;
> +
> +	spin_lock(&dpio_list_lock);
> +	d = list_entry(dpio_list.next, struct dpaa2_io, node);
> +	list_del(&d->node);
> +	list_add_tail(&d->node, &dpio_list);
> +	spin_unlock(&dpio_list_lock);
> +
> +	return d;
> +}
> +
> +/**
> + * dpaa2_io_create() - create a dpaa2_io object.
> + * @desc: the dpaa2_io descriptor
> + *
> + * Activates a "struct dpaa2_io" corresponding to the given config of an
> actual
> + * DPIO object.
> + *
> + * Return a valid dpaa2_io object for success, or NULL for failure.
> + */
> +struct dpaa2_io *dpaa2_io_create(const struct dpaa2_io_desc *desc)
> +{
> +	struct dpaa2_io *obj = kmalloc(sizeof(*obj), GFP_KERNEL);
> +
> +	if (!obj)
> +		return NULL;
> +
> +	/* check if CPU is out of range (-1 means any cpu) */
> +	if (desc->cpu >= NR_CPUS)
> +		return NULL;
> +
> +	atomic_set(&obj->refs, 1);
> +	obj->dpio_desc = *desc;
> +	obj->swp_desc.cena_bar = obj->dpio_desc.regs_cena;
> +	obj->swp_desc.cinh_bar = obj->dpio_desc.regs_cinh;
> +	obj->swp_desc.qman_version = obj->dpio_desc.qman_version;
> +	obj->swp = qbman_swp_init(&obj->swp_desc);
> +
> +	if (!obj->swp) {
> +		kfree(obj);
> +		return NULL;
> +	}
> +
> +	INIT_LIST_HEAD(&obj->node);
> +	spin_lock_init(&obj->lock_mgmt_cmd);
> +	spin_lock_init(&obj->lock_notifications);
> +	INIT_LIST_HEAD(&obj->notifications);
> +
> +	/* For now only enable DQRR interrupts */
> +	qbman_swp_interrupt_set_trigger(obj->swp,
> +					QBMAN_SWP_INTERRUPT_DQRI);
> +	qbman_swp_interrupt_clear_status(obj->swp, 0xffffffff);
> +	if (obj->dpio_desc.receives_notifications)
> +		qbman_swp_push_set(obj->swp, 0, 1);
> +
> +	spin_lock(&dpio_list_lock);
> +	list_add_tail(&obj->node, &dpio_list);
> +	if (desc->cpu >= 0 && !dpio_by_cpu[desc->cpu])
> +		dpio_by_cpu[desc->cpu] = obj;
> +	spin_unlock(&dpio_list_lock);
> +
> +	return obj;
> +}
> +EXPORT_SYMBOL(dpaa2_io_create);
> +
> +/**
> + * dpaa2_io_down() - release the dpaa2_io object.
> + * @d: the dpaa2_io object to be released.
> + *
> + * The "struct dpaa2_io" type can represent an individual DPIO object (as
> + * described by "struct dpaa2_io_desc") or an instance of a "DPIO service",
> + * which can be used to group/encapsulate multiple DPIO objects. In all
> cases,
> + * each handle obtained should be released using this function.
> + */
> +void dpaa2_io_down(struct dpaa2_io *d)
> +{
> +	if (!atomic_dec_and_test(&d->refs))
> +		return;
> +	kfree(d);
> +}
> +EXPORT_SYMBOL(dpaa2_io_down);
> +
> +#define DPAA_POLL_MAX 32
> +
> +/**
> + * dpaa2_io_irq() - ISR for DPIO interrupts
> + *
> + * @obj: the given DPIO object.
> + *
> + * Return IRQ_HANDLED for success or IRQ_NONE if there
> + * were no pending interrupts.
> + */
> +irqreturn_t dpaa2_io_irq(struct dpaa2_io *obj)
> +{
> +	const struct dpaa2_dq *dq;
> +	int max = 0;
> +	struct qbman_swp *swp;
> +	u32 status;
> +
> +	swp = obj->swp;
> +	status = qbman_swp_interrupt_read_status(swp);
> +	if (!status)
> +		return IRQ_NONE;
> +
> +	dq = qbman_swp_dqrr_next(swp);
> +	while (dq) {
> +		if (qbman_result_is_SCN(dq)) {
> +			struct dpaa2_io_notification_ctx *ctx;
> +			u64 q64;
> +
> +			q64 = qbman_result_SCN_ctx(dq);
> +			ctx = (void *)q64;
> +			ctx->cb(ctx);
> +		} else {
> +			pr_crit("fsl-mc-dpio: Unrecognised/ignored DQRR
> entry\n");
> +		}
> +		qbman_swp_dqrr_consume(swp, dq);
> +		++max;
> +		if (max > DPAA_POLL_MAX)
> +			goto done;
> +		dq = qbman_swp_dqrr_next(swp);
> +	}
> +done:
> +	qbman_swp_interrupt_clear_status(swp, status);
> +	qbman_swp_interrupt_set_inhibit(swp, 0);
> +	return IRQ_HANDLED;
> +}
> +EXPORT_SYMBOL(dpaa2_io_irq);
> +
> +/**
> + * dpaa2_io_service_register() - Prepare for servicing of FQDAN or CDAN
> + *                               notifications on the given DPIO service.
> + * @d:   the given DPIO service.
> + * @ctx: the notification context.
> + *
> + * The caller should make the MC command to attach a DPAA2 object to
> + * a DPIO after this function completes successfully.  In that way:
> + *    (a) The DPIO service is "ready" to handle a notification arrival
> + *        (which might happen before the "attach" command to MC has
> + *        returned control of execution back to the caller)
> + *    (b) The DPIO service can provide back to the caller the 'dpio_id' and
> + *        'qman64' parameters that it should pass along in the MC command
> + *        in order for the object to be configured to produce the right
> + *        notification fields to the DPIO service.
> + *
> + * Return 0 for success, or -ENODEV for failure.
> + */
> +int dpaa2_io_service_register(struct dpaa2_io *d,
> +			      struct dpaa2_io_notification_ctx *ctx)
> +{
> +	unsigned long irqflags;
> +
> +	d = service_select_by_cpu(d, ctx->desired_cpu);
> +	if (!d)
> +		return -ENODEV;
> +
> +	ctx->dpio_id = d->dpio_desc.dpio_id;
> +	ctx->qman64 = (u64)ctx;
> +	ctx->dpio_private = d;
> +	spin_lock_irqsave(&d->lock_notifications, irqflags);
> +	list_add(&ctx->node, &d->notifications);
> +	spin_unlock_irqrestore(&d->lock_notifications, irqflags);
> +
> +	/* Enable the generation of CDAN notifications */
> +	if (ctx->is_cdan)
> +		qbman_swp_CDAN_set_context_enable(d->swp,
> +						  (u16)ctx->id,
> +						  ctx->qman64);
> +	return 0;
> +}
> +EXPORT_SYMBOL(dpaa2_io_service_register);
> +
> +/**
> + * dpaa2_io_service_deregister - The opposite of 'register'.
> + * @service: the given DPIO service.
> + * @ctx: the notification context.
> + *
> + * This function should be called only after sending the MC command to
> + * to detach the notification-producing device from the DPIO.
> + */
> +void dpaa2_io_service_deregister(struct dpaa2_io *service,
> +				struct dpaa2_io_notification_ctx *ctx)
> +{
> +	struct dpaa2_io *d = ctx->dpio_private;
> +	unsigned long irqflags;
> +
> +	if (ctx->is_cdan)
> +		qbman_swp_CDAN_disable(d->swp, (u16)ctx->id);
> +
> +	spin_lock_irqsave(&d->lock_notifications, irqflags);
> +	list_del(&ctx->node);
> +	spin_unlock_irqrestore(&d->lock_notifications, irqflags);
> +}
> +EXPORT_SYMBOL(dpaa2_io_service_deregister);
> +
> +/**
> + * dpaa2_io_service_rearm() - Rearm the notification for the given DPIO
> service.
> + * @service: the given DPIO service.
> + * @ctx: the notification context.
> + *
> + * Once a FQDAN/CDAN has been produced, the corresponding FQ/channel
> is
> + * considered "disarmed". Ie. the user can issue pull dequeue operations on
> that
> + * traffic source for as long as it likes. Eventually it may wish to "rearm"
> + * that source to allow it to produce another FQDAN/CDAN, that's what this
> + * function achieves.
> + *
> + * Return 0 for success.
> + */
> +int dpaa2_io_service_rearm(struct dpaa2_io *d,
> +			   struct dpaa2_io_notification_ctx *ctx)
> +{
> +	unsigned long irqflags;
> +	int err;
> +
> +	d = service_select(d);

Why not select the DPIO based on ctx->desired_cpu, like in the initial
notification register?

Thanks,
Ioana

> +	if (!unlikely(d))
> +		return -ENODEV;
> +
> +	spin_lock_irqsave(&d->lock_mgmt_cmd, irqflags);
> +	if (ctx->is_cdan)
> +		err = qbman_swp_CDAN_enable(d->swp, (u16)ctx->id);
> +	else
> +		err = qbman_swp_fq_schedule(d->swp, ctx->id);
> +	spin_unlock_irqrestore(&d->lock_mgmt_cmd, irqflags);
> +
> +	return err;
> +}
> +EXPORT_SYMBOL(dpaa2_io_service_rearm);
[...]

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