Re: [PATCH v2 3/5] soc: add polarfire soc system controller

[Ben Dooks <ben.dooks@codethink.co.uk>]

On 01/12/2020 12:21, Damien Le Moal wrote:
> On 2020/12/01 21:18, Ben Dooks wrote:
>> On 01/12/2020 12:00, Damien Le Moal wrote:
>>> On 2020/12/01 20:03, conor.dooley@microchip.com wrote:
>>>> From: Conor Dooley <conor.dooley@microchip.com>
>>>>
>>>> This driver provides an interface for other drivers to access the
>>>> functions of the system controller on the Microchip PolarFire SoC.
>>>>
>>>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>>>> ---
>>>>    drivers/soc/Kconfig                         |   1 +
>>>>    drivers/soc/Makefile                        |   1 +
>>>>    drivers/soc/microchip/Kconfig               |  10 ++
>>>>    drivers/soc/microchip/Makefile              |   1 +
>>>>    drivers/soc/microchip/mpfs_sys_controller.c | 135 ++++++++++++++++++++
>>>>    5 files changed, 148 insertions(+)
>>>>    create mode 100644 drivers/soc/microchip/Kconfig
>>>>    create mode 100644 drivers/soc/microchip/Makefile
>>>>    create mode 100644 drivers/soc/microchip/mpfs_sys_controller.c
>>>>
>>>> diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
>>>> index 425ab6f7e375..22cb097bcbdc 100644
>>>> --- a/drivers/soc/Kconfig
>>>> +++ b/drivers/soc/Kconfig
>>>> @@ -9,6 +9,7 @@ source "drivers/soc/bcm/Kconfig"
>>>>    source "drivers/soc/fsl/Kconfig"
>>>>    source "drivers/soc/imx/Kconfig"
>>>>    source "drivers/soc/ixp4xx/Kconfig"
>>>> +source "drivers/soc/microchip/Kconfig"
>>>>    source "drivers/soc/mediatek/Kconfig"
>>>>    source "drivers/soc/qcom/Kconfig"
>>>>    source "drivers/soc/renesas/Kconfig"
>>>> diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
>>>> index 36452bed86ef..fb084cf2d12e 100644
>>>> --- a/drivers/soc/Makefile
>>>> +++ b/drivers/soc/Makefile
>>>> @@ -14,6 +14,7 @@ obj-$(CONFIG_ARCH_GEMINI)	+= gemini/
>>>>    obj-y				+= imx/
>>>>    obj-$(CONFIG_ARCH_IXP4XX)	+= ixp4xx/
>>>>    obj-$(CONFIG_SOC_XWAY)		+= lantiq/
>>>> +obj-$(CONFIG_SOC_MICROCHIP_POLARFIRE)	+= microchip/
>>>>    obj-y				+= mediatek/
>>>>    obj-y				+= amlogic/
>>>>    obj-y				+= qcom/
>>>> diff --git a/drivers/soc/microchip/Kconfig b/drivers/soc/microchip/Kconfig
>>>> new file mode 100644
>>>> index 000000000000..40e5203c8ba0
>>>> --- /dev/null
>>>> +++ b/drivers/soc/microchip/Kconfig
>>>> @@ -0,0 +1,10 @@
>>>> +config MPFS_SYS_CONTROLLER
>>>> +	tristate "MPFS_SYS_CONTROLLER"
>>>> +	depends on MPFS_MBOX
>>>> +	help
>>>> +	  This driver adds support for the Polarfire SoC system controller.
>>>> +
>>>> +	  To compile this driver as a module, choose M here. the
>>>> +	  module will be called mpfs_system_controller.
>>>> +
>>>> +	  If unsure, say N.
>>>> diff --git a/drivers/soc/microchip/Makefile b/drivers/soc/microchip/Makefile
>>>> new file mode 100644
>>>> index 000000000000..23b1f42a37db
>>>> --- /dev/null
>>>> +++ b/drivers/soc/microchip/Makefile
>>>> @@ -0,0 +1 @@
>>>> +obj-$(CONFIG_MPFS_SYS_CONTROLLER)	+= mpfs_sys_controller.o
>>>> diff --git a/drivers/soc/microchip/mpfs_sys_controller.c b/drivers/soc/microchip/mpfs_sys_controller.c
>>>> new file mode 100644
>>>> index 000000000000..875a0671e196
>>>> --- /dev/null
>>>> +++ b/drivers/soc/microchip/mpfs_sys_controller.c
>>>> @@ -0,0 +1,135 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +/*
>>>> + * Microchip MPFS system controller driver
>>>> + *
>>>> + * Copyright (c) 2020 Microchip Corporation. All rights reserved.
>>>> + *
>>>> + * Author: Conor Dooley <conor.dooley@microchip.com>
>>>> + *
>>>> + */
>>>> +
>>>> +#include <linux/slab.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/interrupt.h>
>>>> +#include <linux/of_platform.h>
>>>> +#include <linux/mailbox_client.h>
>>>> +#include <linux/platform_device.h>
>>>> +#include <soc/microchip/mpfs.h>
>>>> +
>>>> +static DEFINE_MUTEX(transaction_lock);
>>>> +
>>>> +struct mpfs_sys_controller {
>>>> +	struct mbox_client client;
>>>> +	struct mbox_chan *chan;
>>>> +	struct completion c;
>>>> +	u32 enabled;
>>>> +	void *response;
>>>> +	u16 response_size_bytes;
>>>> +};
>>>> +
>>>> +int mpfs_blocking_transaction(struct mpfs_sys_controller *mpfs_client, void *msg,
>>>> +			      void *response, u16 response_size_bytes)
>>>> +{
>>>> +	int ret;
>>>> +
>>>> +	mpfs_client->response = response;
>>>> +	mpfs_client->response_size_bytes = response_size_bytes;
>>>> +
>>>> +	mutex_lock_interruptible(&transaction_lock);
>>>> +
>>>> +	reinit_completion(&mpfs_client->c);
>>>> +
>>>> +	ret = mbox_send_message(mpfs_client->chan, msg);
>>>> +	if (ret >= 0) {
>>>> +		if (wait_for_completion_timeout(&mpfs_client->c, HZ)) {
>>>> +			ret = 0;
>>>> +		} else {
>>>> +			ret = -ETIMEDOUT;
>>>> +			dev_warn(mpfs_client->client.dev, "MPFS sys controller transaction timeout");
>>>> +		}
>>>> +	} else {
>>>> +		dev_err(mpfs_client->client.dev,
>>>> +			"mpfs sys controller transaction returned %d\r\n", ret);
>>>> +	}
>>>> +
>>>> +	mutex_unlock(&transaction_lock);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL(mpfs_blocking_transaction);
>>>> +
>>>> +static void rx_callback(struct mbox_client *client, void *msg)
>>>> +{
>>>> +	struct mpfs_sys_controller *mpfs_client =
>>>> +		container_of(client, struct mpfs_sys_controller, client);
>>>> +
>>>> +	memcpy(mpfs_client->response, (u8 *)msg,
>>>> +	       mpfs_client->response_size_bytes);
>>>> +
>>>> +	complete(&mpfs_client->c);
>>>> +}
>>>> +
>>>> +static int mpfs_sys_controller_probe(struct platform_device *pdev)
>>>> +{
>>>> +	struct device *dev = &pdev->dev;
>>>> +	struct mpfs_sys_controller *mpfs_client;
>>>> +
>>>> +	mpfs_client = devm_kzalloc(dev, sizeof(*mpfs_client), GFP_KERNEL);
>>>> +	if (!mpfs_client)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	mpfs_client->client.dev = dev;
>>>> +	mpfs_client->client.rx_callback = rx_callback;
>>>> +	mpfs_client->client.tx_block = 1U;
>>>> +
>>>> +	mpfs_client->chan = mbox_request_channel_byname(&mpfs_client->client,
>>>> +							"mbox-mpfs");
>>>> +	if (IS_ERR(mpfs_client->chan)) {
>>>> +		int ret = PTR_ERR(mpfs_client->chan);
>>>> +
>>>> +		if (ret != -EPROBE_DEFER)
>>>> +			dev_err(dev, "Failed to get mbox channel: %d\n", ret);
>>>> +		return ret;
>>>
>>> You can replace all of this with
>>>
>>> 		return dev_err_probe(dev, PTR_ERR(mpfs_client->chan),
>>> 				     ""Failed to get mbox channel\n");
>>
>> you'll spam the error log if you get a lot of probe defferals.
>> I think the code as is fine.
> 
> Please look at that function code: it does not print anything if the error is
> -EPROBE_DEFER.
> 

ah, ok.




-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

https://www.codethink.co.uk/privacy.html