Re: [PATCH v6 4/4] mailbox: Introduce Qualcomm APCS IPC driver

[Stephen Boyd <sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>]

On 05/09, Bjorn Andersson wrote:
> This implements a driver that exposes the IPC bits found in the APCS
> Global block in various Qualcomm platforms. The bits are used to signal
> inter-processor communication signals from the application CPU to other
> masters.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
> 
> Changes since v5:
> - Set txdone_none
> 
>  drivers/mailbox/Kconfig                 |   8 ++
>  drivers/mailbox/Makefile                |   2 +
>  drivers/mailbox/qcom-apcs-ipc-mailbox.c | 129 ++++++++++++++++++++++++++++++++

Drive by trivia!

>  3 files changed, 139 insertions(+)
>  create mode 100644 drivers/mailbox/qcom-apcs-ipc-mailbox.c
> 
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index ceff415f201c..fffc64da61f9 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -124,6 +124,14 @@ config MAILBOX_TEST
>  	  Test client to help with testing new Controller driver
>  	  implementations.
>  
> +config QCOM_APCS_IPC
> +	tristate "Qualcomm APCS IPC driver"
> +	depends on ARCH_QCOM

Plus an || COMPILE_TEST?

> +	help
> +	  Say y here to enable support for the APCS IPC mailbox driver,
> +	  providing an interface for invoking the inter-process communication
> +	  signals from the application processor to other masters.
> +
> diff --git a/drivers/mailbox/qcom-apcs-ipc-mailbox.c b/drivers/mailbox/qcom-apcs-ipc-mailbox.c
> new file mode 100644
> index 000000000000..4dddf8627acc
> --- /dev/null
> +++ b/drivers/mailbox/qcom-apcs-ipc-mailbox.c
> @@ -0,0 +1,129 @@
> +/*
> + * Copyright (c) 2017, Linaro Ltd
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/slab.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/mailbox_controller.h>
> +
> +#define QCOM_APCS_IPC_BITS	32
> +
> +struct qcom_apcs_ipc {
> +	struct device *dev;

Is this used? I guess it's nice for dev_*() messages, but it
doesn't seem used.

> +
> +	struct mbox_controller mbox;
> +	struct mbox_chan mbox_chans[QCOM_APCS_IPC_BITS];
> +
> +	void __iomem *base;
> +	unsigned long offset;
> +};
> +
> +static int qcom_apcs_ipc_send_data(struct mbox_chan *chan, void *data)
> +{
> +	struct qcom_apcs_ipc *apcs = container_of(chan->mbox,
> +						  struct qcom_apcs_ipc, mbox);
> +	unsigned long idx = (unsigned long)chan->con_priv;
> +
> +	writel(BIT(idx), apcs->base + apcs->offset);

Do we need both base and offset? We can just store the "doorbell"
register and then ping the right bit instead.

> +
> +	return 0;
> +}
> +
> +static const struct mbox_chan_ops qcom_apcs_ipc_ops = {
> +	.send_data = qcom_apcs_ipc_send_data,
> +};
> +
> +static int qcom_apcs_ipc_probe(struct platform_device *pdev)
> +{
> +	struct qcom_apcs_ipc *apcs;
> +	struct resource *res;
> +	unsigned long i;
> +	int ret;
> +
> +	apcs = devm_kzalloc(&pdev->dev, sizeof(*apcs), GFP_KERNEL);
> +	if (!apcs)
> +		return -ENOMEM;
> +
> +	apcs->dev = &pdev->dev;
> +	apcs->offset = (unsigned long)of_device_get_match_data(&pdev->dev);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	apcs->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(apcs->base))
> +		return PTR_ERR(apcs->base);
> +
> +	/* Initialize channel identifiers */
> +	for (i = 0; i < ARRAY_SIZE(apcs->mbox_chans); i++)
> +		apcs->mbox_chans[i].con_priv = (void *)i;
> +
> +	apcs->mbox.dev = &pdev->dev;
> +	apcs->mbox.ops = &qcom_apcs_ipc_ops;
> +	apcs->mbox.txdone_none = true;
> +	apcs->mbox.chans = apcs->mbox_chans;
> +	apcs->mbox.num_chans = ARRAY_SIZE(apcs->mbox_chans);
> +
> +	ret = mbox_controller_register(&apcs->mbox);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to register APCS IPC controller\n");
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, apcs);
> +
> +	return 0;
> +}
> +
> +static int qcom_apcs_ipc_remove(struct platform_device *pdev)
> +{
> +	struct qcom_apcs_ipc *apcs = platform_get_drvdata(pdev);
> +
> +	mbox_controller_unregister(&apcs->mbox);

Too bad there isn't a devm_mbox_controller_register()!

> +
> +	return 0;
> +}
> +

-- 
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