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

[Ben Dooks]

On 01/12/2020 12:00, Damien Le Moal wrote:
> On 2020/12/01 20:03, conor.dooley at microchip.com wrote:
>> From: Conor Dooley <conor.dooley at 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 at 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 at 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.




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

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