Re: [PATCH V6 5/8] soundwire: amd: add SoundWire manager interrupt handling

["Mukunda,Vijendar via Alsa-devel" <alsa-devel@xxxxxxxxxxxxxxxx>]

--- Begin Message ---

• To: Vinod Koul <vkoul@xxxxxxxxxx>
• Subject: Re: [PATCH V6 5/8] soundwire: amd: add SoundWire manager interrupt handling
• From: "Mukunda,Vijendar" <vijendar.mukunda@xxxxxxx>
• Date: Thu, 16 Mar 2023 22:34:46 +0530
• Cc: alsa-devel@xxxxxxxxxxxxxxxx, pierre-louis.bossart@xxxxxxxxxxxxxxx, Basavaraj.Hiregoudar@xxxxxxx, Sunil-kumar.Dommati@xxxxxxx, Mario.Limonciello@xxxxxxx, amadeuszx.slawinski@xxxxxxxxxxxxxxx, Mastan.Katragadda@xxxxxxx, Arungopal.kondaveeti@xxxxxxx, claudiu.beznea@xxxxxxxxxxxxx, Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>, Sanyog Kale <sanyog.r.kale@xxxxxxxxx>, open list <linux-kernel@xxxxxxxxxxxxxxx>
• In-reply-to: <ZBGYubOYyu7E8ueo@matsya>
• References: <20230307133135.545952-1-Vijendar.Mukunda@amd.com> <20230307133135.545952-6-Vijendar.Mukunda@amd.com> <ZBGYubOYyu7E8ueo@matsya>
• User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0

On 15/03/23 15:36, Vinod Koul wrote:
> On 07-03-23, 19:01, Vijendar Mukunda wrote:
>> Add support for handling SoundWire manager interrupts.
>>
>> Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@xxxxxxx>
>> Signed-off-by: Mastan Katragadda <Mastan.Katragadda@xxxxxxx>
>> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
>> Link: https://lore.kernel.org/lkml/20230227154801.50319-6-Vijendar.Mukunda@xxxxxxx
>> ---
>>  drivers/soundwire/amd_manager.c   | 130 ++++++++++++++++++++++++++++++
>>  drivers/soundwire/amd_manager.h   |   1 +
>>  include/linux/soundwire/sdw_amd.h |   7 ++
>>  3 files changed, 138 insertions(+)
>>
>> diff --git a/drivers/soundwire/amd_manager.c b/drivers/soundwire/amd_manager.c
>> index dd7fd4036d89..165078beca2e 100644
>> --- a/drivers/soundwire/amd_manager.c
>> +++ b/drivers/soundwire/amd_manager.c
>> @@ -357,6 +357,51 @@ static enum sdw_command_response amd_sdw_xfer_msg(struct sdw_bus *bus, struct sd
>>  	return SDW_CMD_OK;
>>  }
>>  
>> +static void amd_sdw_fill_slave_status(struct amd_sdw_manager *amd_manager, u16 index, u32 status)
>> +{
>> +	switch (status) {
>> +	case SDW_SLAVE_ATTACHED:
>> +		amd_manager->status[index] = SDW_SLAVE_ATTACHED;
>> +		break;
>> +	case SDW_SLAVE_UNATTACHED:
>> +		amd_manager->status[index] = SDW_SLAVE_UNATTACHED;
>> +		break;
>> +	case SDW_SLAVE_ALERT:
>> +		amd_manager->status[index] = SDW_SLAVE_ALERT;
>> +		break;
> why not:
>
>         case SDW_SLAVE_ATTACHED:
>         case SDW_SLAVE_UNATTACHED:
>         case SDW_SLAVE_ALERT:
>                 amd_manager->status[index] = status;
>                 break;
>
> Will fix it.
>> +	default:
>> +		amd_manager->status[index] = SDW_SLAVE_RESERVED;
>> +		break;
>> +	}
>> +}
>> +
>> +static void amd_sdw_process_ping_status(u64 response, struct amd_sdw_manager *amd_manager)
>> +{
>> +	u64 slave_stat;
>> +	u32 val;
>> +	u16 dev_index;
>> +
>> +	/* slave status response */
>> +	slave_stat = FIELD_GET(AMD_SDW_MCP_SLAVE_STAT_0_3, response);
>> +	slave_stat |= FIELD_GET(AMD_SDW_MCP_SLAVE_STAT_4_11, response) << 8;
>> +	dev_dbg(amd_manager->dev, "slave_stat:0x%llx\n", slave_stat);
>> +	for (dev_index = 0; dev_index <= SDW_MAX_DEVICES; ++dev_index) {
>> +		val = (slave_stat >> (dev_index * 2)) & AMD_SDW_MCP_SLAVE_STATUS_MASK;
>> +		dev_dbg(amd_manager->dev, "val:0x%x\n", val);
>> +		amd_sdw_fill_slave_status(amd_manager, dev_index, val);
>> +	}
>> +}
>> +
>> +static void amd_sdw_read_and_process_ping_status(struct amd_sdw_manager *amd_manager)
>> +{
>> +	u64 response;
>> +
>> +	mutex_lock(&amd_manager->bus.msg_lock);
>> +	response = amd_sdw_send_cmd_get_resp(amd_manager, 0, 0);
>> +	mutex_unlock(&amd_manager->bus.msg_lock);
>> +	amd_sdw_process_ping_status(response, amd_manager);
>> +}
>> +
>>  static u32 amd_sdw_read_ping_status(struct sdw_bus *bus)
>>  {
>>  	struct amd_sdw_manager *amd_manager = to_amd_sdw(bus);
>> @@ -757,6 +802,89 @@ static int amd_sdw_register_dais(struct amd_sdw_manager *amd_manager)
>>  					       dais, num_dais);
>>  }
>>  
>> +static void amd_sdw_update_slave_status_work(struct work_struct *work)
>> +{
>> +	struct amd_sdw_manager *amd_manager =
>> +		container_of(work, struct amd_sdw_manager, amd_sdw_work);
>> +	int retry_count = 0;
>> +
>> +	if (amd_manager->status[0] == SDW_SLAVE_ATTACHED) {
>> +		acp_reg_writel(0, amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_MASK_0TO7);
>> +		acp_reg_writel(0, amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_MASK_8TO11);
>> +	}
>> +
>> +update_status:
>> +	sdw_handle_slave_status(&amd_manager->bus, amd_manager->status);
>> +	/*
>> +	 * During the peripheral enumeration sequence, the SoundWire manager interrupts
>> +	 * are masked. Once the device number programming is done for all peripherals,
>> +	 * interrupts will be unmasked. Read the peripheral device status from ping command
>> +	 * and process the response. This sequence will ensure all peripheral devices enumerated
>> +	 * and initialized properly.
>> +	 */
>> +	if (amd_manager->status[0] == SDW_SLAVE_ATTACHED) {
>> +		if (retry_count++ < SDW_MAX_DEVICES) {
>> +			acp_reg_writel(AMD_SDW_IRQ_MASK_0TO7, amd_manager->mmio +
>> +				       ACP_SW_STATE_CHANGE_STATUS_MASK_0TO7);
>> +			acp_reg_writel(AMD_SDW_IRQ_MASK_8TO11,
>> +				       amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_MASK_8TO11);
>> +			amd_sdw_read_and_process_ping_status(amd_manager);
>> +			goto update_status;
> goto are mostly used for error handling, i dont thing case here deserves
> a goto, can you please change this...
I agree. goto statements will be used mostly for error handling.
But this is a different scenario. We have used goto statement to call sdw_handle_slave_status()
from if statement to make sure all peripheral devices are enumerated and initialized properly.
Please let us know if you are expecting code to be modified as mentioned below.

sdw_handle_slave_status(&amd_manager->bus, amd_manager->status);

if (amd_manager->status[0] == SDW_SLAVE_ATTACHED) {
	acp_reg_writel(AMD_SDW_IRQ_MASK_0TO7, amd_manager->mmio +
		       ACP_SW_STATE_CHANGE_STATUS_MASK_0TO7);
	acp_reg_writel(AMD_SDW_IRQ_MASK_8TO11,
		       amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_MASK_8TO11);
	amd_sdw_read_and_process_ping_status(amd_manager);
	sdw_handle_slave_status(&amd_manager->bus, amd_manager->status);
}

We have to check any race conditions occurs or not if we implement code as mentioned
above.
IMHO, it is still good to go with goto statement implementation.
>> +		} else {
>> +			dev_err_ratelimited(amd_manager->dev,
>> +					    "Device0 detected after %d iterations\n",
>> +					    retry_count);
>> +		}
>> +	}
>> +}
>> +
>> +static void amd_sdw_update_slave_status(u32 status_change_0to7, u32 status_change_8to11,
>> +					struct amd_sdw_manager *amd_manager)
>> +{
>> +	u64 slave_stat;
>> +	u32 val;
>> +	int dev_index;
>> +
>> +	if (status_change_0to7 == AMD_SDW_SLAVE_0_ATTACHED)
>> +		memset(amd_manager->status, 0, sizeof(amd_manager->status));
>> +	slave_stat = status_change_0to7;
>> +	slave_stat |= FIELD_GET(AMD_SDW_MCP_SLAVE_STATUS_8TO_11, status_change_8to11) << 32;
>> +	dev_dbg(amd_manager->dev, "status_change_0to7:0x%x status_change_8to11:0x%x\n",
>> +		status_change_0to7, status_change_8to11);
>> +	if (slave_stat) {
>> +		for (dev_index = 0; dev_index <= SDW_MAX_DEVICES; ++dev_index) {
>> +			if (slave_stat & AMD_SDW_MCP_SLAVE_STATUS_VALID_MASK(dev_index)) {
>> +				val = (slave_stat >> AMD_SDW_MCP_SLAVE_STAT_SHIFT_MASK(dev_index)) &
>> +				      AMD_SDW_MCP_SLAVE_STATUS_MASK;
>> +				amd_sdw_fill_slave_status(amd_manager, dev_index, val);
>> +			}
>> +		}
>> +	}
>> +}
>> +
>> +static void amd_sdw_irq_thread(struct work_struct *work)
>> +{
>> +	struct amd_sdw_manager *amd_manager =
>> +			container_of(work, struct amd_sdw_manager, amd_sdw_irq_thread);
>> +	u32 status_change_8to11;
>> +	u32 status_change_0to7;
>> +
>> +	status_change_8to11 = acp_reg_readl(amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_8TO11);
>> +	status_change_0to7 = acp_reg_readl(amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_0TO7);
>> +	dev_dbg(amd_manager->dev, "[SDW%d] SDW INT: 0to7=0x%x, 8to11=0x%x\n",
>> +		amd_manager->instance, status_change_0to7, status_change_8to11);
>> +	if (status_change_8to11 & AMD_SDW_PREQ_INTR_STAT) {
>> +		amd_sdw_read_and_process_ping_status(amd_manager);
>> +	} else {
>> +		/* Check for the updated status on peripheral device */
>> +		amd_sdw_update_slave_status(status_change_0to7, status_change_8to11, amd_manager);
>> +	}
>> +	if (status_change_8to11 || status_change_0to7)
>> +		schedule_work(&amd_manager->amd_sdw_work);
>> +	acp_reg_writel(0x00, amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_8TO11);
>> +	acp_reg_writel(0x00, amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_0TO7);
>> +}
>> +
>>  static void amd_sdw_probe_work(struct work_struct *work)
>>  {
>>  	struct amd_sdw_manager *amd_manager = container_of(work, struct amd_sdw_manager,
>> @@ -847,6 +975,8 @@ static int amd_sdw_manager_probe(struct platform_device *pdev)
>>  		return ret;
>>  	}
>>  	dev_set_drvdata(dev, amd_manager);
>> +	INIT_WORK(&amd_manager->amd_sdw_irq_thread, amd_sdw_irq_thread);
>> +	INIT_WORK(&amd_manager->amd_sdw_work, amd_sdw_update_slave_status_work);
>>  	INIT_WORK(&amd_manager->probe_work, amd_sdw_probe_work);
>>  	/*
>>  	 * Instead of having lengthy probe sequence, use deferred probe.
>> diff --git a/drivers/soundwire/amd_manager.h b/drivers/soundwire/amd_manager.h
>> index cad26034087b..807bc5a314d8 100644
>> --- a/drivers/soundwire/amd_manager.h
>> +++ b/drivers/soundwire/amd_manager.h
>> @@ -185,6 +185,7 @@
>>  #define AMD_SDW1_PAD_KEEPER_EN_MASK			0x10
>>  #define AMD_SDW0_PAD_KEEPER_DISABLE_MASK		0x1E
>>  #define AMD_SDW1_PAD_KEEPER_DISABLE_MASK		0xF
>> +#define AMD_SDW_PREQ_INTR_STAT				BIT(19)
>>  
>>  enum amd_sdw_cmd_type {
>>  	AMD_SDW_CMD_PING = 0,
>> diff --git a/include/linux/soundwire/sdw_amd.h b/include/linux/soundwire/sdw_amd.h
>> index ac537419301d..df60bc0de6fc 100644
>> --- a/include/linux/soundwire/sdw_amd.h
>> +++ b/include/linux/soundwire/sdw_amd.h
>> @@ -45,8 +45,11 @@ struct sdw_amd_dai_runtime {
>>   * @mmio: SoundWire registers mmio base
>>   * @acp_mmio: acp registers mmio base
>>   * @reg_mask: register mask structure per manager instance
>> + * @amd_sdw_irq_thread: SoundWire manager irq workqueue
>> + * @amd_sdw_work: peripheral status work queue
>>   * @probe_work: SoundWire manager probe workqueue
>>   * @acp_sdw_lock: mutex to protect acp share register access
>> + * @status: peripheral devices status array
>>   * @num_din_ports: number of input ports
>>   * @num_dout_ports: number of output ports
>>   * @cols_index: Column index in frame shape
>> @@ -65,10 +68,14 @@ struct amd_sdw_manager {
>>  	void __iomem *acp_mmio;
>>  
>>  	struct sdw_manager_reg_mask *reg_mask;
>> +	struct work_struct amd_sdw_irq_thread;
>> +	struct work_struct amd_sdw_work;
>>  	struct work_struct probe_work;
>>  	/* mutex to protect acp common register access */
>>  	struct mutex *acp_sdw_lock;
>>  
>> +	enum sdw_slave_status status[SDW_MAX_DEVICES + 1];
>> +
>>  	int num_din_ports;
>>  	int num_dout_ports;
>>  
>> -- 
>> 2.34.1

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