Message-ID: <591d19d9-9d98-0d4c-c061-759dc5dec738@amd.com>
Date:   Wed, 22 Feb 2023 12:48:02 +0530
From:   "Mukunda,Vijendar" <vijendar.mukunda@....com>
To:     Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        vkoul@...nel.org
Cc:     alsa-devel@...a-project.org, amadeuszx.slawinski@...ux.intel.com,
        Mario.Limonciello@....com, Sunil-kumar.Dommati@....com,
        Basavaraj.Hiregoudar@....com, Mastan.Katragadda@....com,
        Arungopal.kondaveeti@....com,
        Bard Liao <yung-chuan.liao@...ux.intel.com>,
        Sanyog Kale <sanyog.r.kale@...el.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V3 2/8] soundwire: amd: Add support for AMD Manager driver

On 21/02/23 21:27, Pierre-Louis Bossart wrote:
>> +static int amd_init_sdw_manager(struct amd_sdw_manager *amd_manager)
>> +{
>> +	u32 val;
>> +	u32 timeout = 0;
>> +	u32 retry_count = 0;
>> +
>> +	acp_reg_writel(AMD_SDW_ENABLE, amd_manager->mmio + ACP_SW_EN);
>> +	do {
>> +		val = acp_reg_readl(amd_manager->mmio + ACP_SW_EN_STATUS);
>> +		if (val)
>> +			break;
>> +		usleep_range(10, 50);
> that's a 5x range used for all usleep_range() in this file, is this
> intentional?
>
usleep_range(10, 20) will be enough.
Will fix it.
>> +	} while (retry_count++ < AMD_SDW_STAT_MAX_RETRY_COUNT);
>> +
>> +	if (retry_count > AMD_SDW_STAT_MAX_RETRY_COUNT)
>> +		return -ETIMEDOUT;
>> +
>> +	/* SoundWire manager bus reset */
>> +	acp_reg_writel(AMD_SDW_BUS_RESET_REQ, amd_manager->mmio + ACP_SW_BUS_RESET_CTRL);
>> +	val = acp_reg_readl(amd_manager->mmio + ACP_SW_BUS_RESET_CTRL);
>> +	while (!(val & AMD_SDW_BUS_RESET_DONE)) {
>> +		val = acp_reg_readl(amd_manager->mmio + ACP_SW_BUS_RESET_CTRL);
>> +		if (timeout > AMD_DELAY_LOOP_ITERATION)
>> +			break;
> so if you break here...
>
>> +		usleep_range(1, 5);
>> +		timeout++;
>> +	}
>> +	if (timeout == AMD_DELAY_LOOP_ITERATION)
>> +		return -ETIMEDOUT;
> ... this test will never be used. the timeout management looks wrong?
Yes it overlooked.  Will fix it.
>> +	timeout = 0;
>> +	acp_reg_writel(AMD_SDW_BUS_RESET_CLEAR_REQ, amd_manager->mmio + ACP_SW_BUS_RESET_CTRL);
>> +	val = acp_reg_readl(amd_manager->mmio + ACP_SW_BUS_RESET_CTRL);
>> +	while (val) {
>> +		val = acp_reg_readl(amd_manager->mmio + ACP_SW_BUS_RESET_CTRL);
>> +		if (timeout > AMD_DELAY_LOOP_ITERATION)
>> +			break;
> same here...

>> +		usleep_range(1, 5);
>> +		timeout++;
>> +	}
>> +	if (timeout == AMD_DELAY_LOOP_ITERATION) {
> ... and here.
will fix it.
>> +		dev_err(amd_manager->dev, "Failed to reset SoundWire manager instance%d\n",
>> +			amd_manager->instance);
>> +		return -ETIMEDOUT;
>> +	}
>> +	retry_count = 0;
>> +	acp_reg_writel(AMD_SDW_DISABLE, amd_manager->mmio + ACP_SW_EN);
>> +	do {
>> +		val = acp_reg_readl(amd_manager->mmio + ACP_SW_EN_STATUS);
>> +		if (!val)
>> +			break;
>> +		usleep_range(10, 50);
>> +	} while (retry_count++ < AMD_SDW_STAT_MAX_RETRY_COUNT);
>> +
>> +	if (retry_count > AMD_SDW_STAT_MAX_RETRY_COUNT)
>> +		return -ETIMEDOUT;
> that one looks correct though.
>
>> +	return 0;
>> +}
>> +static void amd_enable_sdw_interrupts(struct amd_sdw_manager *amd_manager)
>> +{
>> +	struct sdw_manager_reg_mask *reg_mask = amd_manager->reg_mask;
>> +	u32 val;
>> +
>> +	mutex_lock(amd_manager->acp_sdw_lock);
>> +	val = acp_reg_readl(amd_manager->acp_mmio + ACP_EXTERNAL_INTR_CNTL(amd_manager->instance));
>> +	val |= reg_mask->acp_sdw_intr_mask;
>> +	acp_reg_writel(val, amd_manager->acp_mmio + ACP_EXTERNAL_INTR_CNTL(amd_manager->instance));
> here you handle a read-modify-write sequence on the INTL_CNTL register...
>
>> +	val = acp_reg_readl(amd_manager->acp_mmio + ACP_EXTERNAL_INTR_CNTL(amd_manager->instance));
> ... but here you only read from the same register. what's the purpose of
> this read?
This read to print the register value.
This register read is really not required. we can drop dev_dbg() statement.
>> +	mutex_unlock(amd_manager->acp_sdw_lock);
>> +	dev_dbg(amd_manager->dev, "acp_ext_intr_ctrl[0x%x]:0x%x\n",
>> +		ACP_EXTERNAL_INTR_CNTL(amd_manager->instance), val);
>> +	val = acp_reg_readl(amd_manager->acp_mmio + ACP_EXTERNAL_INTR_STAT(amd_manager->instance));
>> +	if (val)
>> +		acp_reg_writel(val, amd_manager->acp_mmio +
>> +			       ACP_EXTERNAL_INTR_STAT(amd_manager->instance));
we will also remove ACP_EXTERNAL_INTR_STAT register update code.
This change has side effects.
ACP_EXTERNAL_INTR_STAT register should be updated in ACP PCI driver(parent driver) IRQ handler.


>> +
>> +	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);
>> +	acp_reg_writel(AMD_SDW_IRQ_ERROR_MASK, amd_manager->mmio + ACP_SW_ERROR_INTR_MASK);
> can you explain why the writes are not protected by the mutex?

ACP_SW_STATE_CHANGE_STATUS_MASK_0TO7, ACP_SW_STATE_CHANGE_STATUS_MASK_8TO11, ACP_SW_ERROR_INTR_MASK registers
are soundwire manager instance specific registers whereas ACP_EXTERNAL_INTR_CNTL register is part of ACP common
space registers will be accessed by ACP PCI driver and other DMA driver modules, which needs to be protected by mutex
lock.


>> +}
>> +
>> +static void amd_disable_sdw_interrupts(struct amd_sdw_manager *amd_manager)
>> +{
>> +	struct sdw_manager_reg_mask *reg_mask = amd_manager->reg_mask;
>> +	u32 val;
>> +
>> +	mutex_lock(amd_manager->acp_sdw_lock);
>> +	val = acp_reg_readl(amd_manager->acp_mmio + ACP_EXTERNAL_INTR_CNTL(amd_manager->instance));
>> +	val &= ~reg_mask->acp_sdw_intr_mask;
>> +	acp_reg_writel(val, amd_manager->acp_mmio + ACP_EXTERNAL_INTR_CNTL(amd_manager->instance));
> you don't have the read here as in the enable sequence to presumably
> that wasn't needed?
please refer above reply.
>> +	mutex_unlock(amd_manager->acp_sdw_lock);
>> +
>> +	acp_reg_writel(0x00, amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_MASK_0TO7);
>> +	acp_reg_writel(0x00, amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_MASK_8TO11);
>> +	acp_reg_writel(0x00, amd_manager->mmio + ACP_SW_ERROR_INTR_MASK);
> same, not clear why the writes are not protected?
please refer above reply.
>> +}
> ...
>
>> +static u64 amd_sdw_send_cmd_get_resp(struct amd_sdw_manager *amd_manager, u32 lword, u32 uword)
>> +{
>> +	u64 resp;
>> +	u32 resp_lower, resp_high;
>> +	u32 sts;
>> +	u32 timeout = 0;
>> +
>> +	sts = acp_reg_readl(amd_manager->mmio + ACP_SW_IMM_CMD_STS);
>> +	while (sts & AMD_SDW_IMM_CMD_BUSY) {
>> +		sts = acp_reg_readl(amd_manager->mmio + ACP_SW_IMM_CMD_STS);
>> +		if (timeout > AMD_SDW_RETRY_COUNT) {
>> +			dev_err(amd_manager->dev, "SDW%x previous cmd status clear failed\n",
>> +				amd_manager->instance);
>> +			return -ETIMEDOUT;
>> +		}
>> +		timeout++;
> no usleep_range() here?
will fix it by using usleep_range(5, 10).

> Also is there any merit in using the same retry count across the board,
> this is about command handling, not enabling the hardware - presumably
> this should be tied to the SoundWire bus frame timing, not internal delays.
>
>> +	}
>> +
>> +	timeout = 0;
>> +	if (sts & AMD_SDW_IMM_RES_VALID) {
>> +		dev_err(amd_manager->dev, "SDW%x manager is in bad state\n", amd_manager->instance);
>> +		acp_reg_writel(0x00, amd_manager->mmio + ACP_SW_IMM_CMD_STS);
>> +	}
>> +	acp_reg_writel(uword, amd_manager->mmio + ACP_SW_IMM_CMD_UPPER_WORD);
>> +	acp_reg_writel(lword, amd_manager->mmio + ACP_SW_IMM_CMD_LOWER_QWORD);
>> +
>> +	sts = acp_reg_readl(amd_manager->mmio + ACP_SW_IMM_CMD_STS);
>> +	while (!(sts & AMD_SDW_IMM_RES_VALID)) {
>> +		sts = acp_reg_readl(amd_manager->mmio + ACP_SW_IMM_CMD_STS);
>> +		if (timeout > AMD_SDW_RETRY_COUNT) {
>> +			dev_err(amd_manager->dev, "SDW%x cmd response timeout occurred\n",
>> +				amd_manager->instance);
>> +			return -ETIMEDOUT;
> usleep_range?
will fix it by using usleep_range(5, 10).
>> +		}
>> +		timeout++;
>> +	}
>> +	resp_high = acp_reg_readl(amd_manager->mmio + ACP_SW_IMM_RESP_UPPER_WORD);
>> +	resp_lower = acp_reg_readl(amd_manager->mmio + ACP_SW_IMM_RESP_LOWER_QWORD);
>> +	timeout = 0;
>> +	acp_reg_writel(AMD_SDW_IMM_RES_VALID, amd_manager->mmio + ACP_SW_IMM_CMD_STS);
>> +	while ((sts & AMD_SDW_IMM_RES_VALID)) {
>> +		sts = acp_reg_readl(amd_manager->mmio + ACP_SW_IMM_CMD_STS);
>> +		if (timeout > AMD_SDW_RETRY_COUNT) {
>> +			dev_err(amd_manager->dev, "SDW%x cmd status retry failed\n",
>> +				amd_manager->instance);
>> +			return -ETIMEDOUT;
>> +		}
>> +		timeout++;
> usleep_range() ?
will fix it by using usleep_range(5, 10).
>> +	}
>> +	resp = resp_high;
>> +	resp = (resp << 32) | resp_lower;
>> +	return resp;
>> +}
>> +
>> +static enum sdw_command_response
>> +amd_program_scp_addr(struct amd_sdw_manager *amd_manager, struct sdw_msg *msg)
>> +{
>> +	struct sdw_msg scp_msg = {0};
>> +	u64 response_buf[2] = {0};
>> +	u32 uword = 0, lword = 0;
>> +	int nack = 0, no_ack = 0;
>> +	int index, timeout = 0;
>> +
>> +	scp_msg.dev_num = msg->dev_num;
>> +	scp_msg.addr = SDW_SCP_ADDRPAGE1;
>> +	scp_msg.buf = &msg->addr_page1;
>> +	amd_sdw_ctl_word_prep(&lword, &uword, AMD_SDW_CMD_WRITE, &scp_msg, 0);
>> +	response_buf[0] = amd_sdw_send_cmd_get_resp(amd_manager, lword, uword);
>> +	scp_msg.addr = SDW_SCP_ADDRPAGE2;
>> +	scp_msg.buf = &msg->addr_page2;
>> +	amd_sdw_ctl_word_prep(&lword, &uword, AMD_SDW_CMD_WRITE, &scp_msg, 0);
>> +	response_buf[1] = amd_sdw_send_cmd_get_resp(amd_manager, lword, uword);
>> +
>> +	/* check response the writes */
> revisit comment, grammar does not add up - missing to/if/after?
will fix it.
>> +	for (index = 0; index < 2; index++) {
> what is the 2 here?
2 denotes SCP commands response buffer count.
>> +		if (response_buf[index] == -ETIMEDOUT) {
>> +			dev_err(amd_manager->dev, "Program SCP cmd timeout\n");
> that's one log here, possibly 2 ...
we are checking inside loop.
>> +			timeout = 1;
>> +		} else if (!(response_buf[index] & AMD_SDW_MCP_RESP_ACK)) {
>> +			no_ack = 1;
>> +			if (response_buf[index] & AMD_SDW_MCP_RESP_NACK) {
>> +				nack = 1;
>> +				dev_err(amd_manager->dev, "Program SCP NACK received\n");
>> +			}
>> +		}
>> +	}
>> +
>> +	if (timeout) {
>> +		dev_err_ratelimited(amd_manager->dev,
>> +				    "SCP_addrpage command timeout for Slave %d\n", msg->dev_num);
> ... and one more here. Is this needed/useful?
Even if any one of the scp command response reports timeout , we need to return timeout
error.
>> +		return SDW_CMD_TIMEOUT;
>> +	}
>> +
>> +	if (nack) {
>> +		dev_err_ratelimited(amd_manager->dev,
>> +				    "SCP_addrpage NACKed for Slave %d\n", msg->dev_num);
>> +		return SDW_CMD_FAIL;
>> +	}
>> +
>> +	if (no_ack) {
>> +		dev_dbg_ratelimited(amd_manager->dev,
>> +				    "SCP_addrpage ignored for Slave %d\n", msg->dev_num);
>> +		return SDW_CMD_IGNORED;
>> +	}
>> +	return SDW_CMD_OK;
>> +}
>> +static int amd_sdw_manager_probe(struct platform_device *pdev)
>> +{
>> +	const struct acp_sdw_pdata *pdata = pdev->dev.platform_data;
>> +	struct resource *res;
>> +	struct device *dev = &pdev->dev;
>> +	struct sdw_master_prop *prop;
>> +	struct sdw_bus_params *params;
>> +	struct amd_sdw_manager *amd_manager;
>> +	int ret;
>> +
>> +	if (!pdev->dev.platform_data) {
>> +		dev_err(dev, "platform_data not retrieved\n");
> can this happen?
not needed. we can drop this check.
>> +		return -ENODEV;
>> +	}
>> +	amd_manager = devm_kzalloc(dev, sizeof(struct amd_sdw_manager), GFP_KERNEL);
>> +	if (!amd_manager)
>> +		return -ENOMEM;
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	if (!res)
>> +		return -ENOMEM;
>> +	amd_manager->acp_mmio = devm_ioremap(dev, res->start, resource_size(res));
>> +	if (IS_ERR(amd_manager->mmio)) {
>> +		dev_err(dev, "mmio not found\n");
>> +		return PTR_ERR(amd_manager->mmio);
>> +	}
>> +	amd_manager->instance = pdata->instance;
>> +	amd_manager->mmio = amd_manager->acp_mmio +
>> +			    (amd_manager->instance * SDW_MANAGER_REG_OFFSET);
>> +	amd_manager->acp_sdw_lock = pdata->acp_sdw_lock;
>> +	amd_manager->cols_index = sdw_find_col_index(AMD_SDW_DEFAULT_COLUMNS);
>> +	amd_manager->rows_index = sdw_find_row_index(AMD_SDW_DEFAULT_ROWS);
>> +	amd_manager->dev = dev;
>> +	amd_manager->bus.ops = &amd_sdw_ops;
>> +	amd_manager->bus.port_ops = &amd_sdw_port_ops;
>> +	amd_manager->bus.compute_params = &amd_sdw_compute_params;
>> +	amd_manager->bus.clk_stop_timeout = 200;
>> +	amd_manager->bus.link_id = amd_manager->instance;
>> +	switch (amd_manager->instance) {
>> +	case ACP_SDW0:
>> +		amd_manager->num_dout_ports = AMD_SDW0_MAX_TX_PORTS;
>> +		amd_manager->num_din_ports = AMD_SDW0_MAX_RX_PORTS;
>> +		break;
>> +	case ACP_SDW1:
>> +		amd_manager->num_dout_ports = AMD_SDW1_MAX_TX_PORTS;
>> +		amd_manager->num_din_ports = AMD_SDW1_MAX_RX_PORTS;
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +	amd_manager->reg_mask = &sdw_manager_reg_mask_array[amd_manager->instance];
>> +	params = &amd_manager->bus.params;
>> +	params->max_dr_freq = AMD_SDW_DEFAULT_CLK_FREQ * 2;
>> +	params->curr_dr_freq = AMD_SDW_DEFAULT_CLK_FREQ * 2;
>> +	params->col = AMD_SDW_DEFAULT_COLUMNS;
>> +	params->row = AMD_SDW_DEFAULT_ROWS;
>> +	prop = &amd_manager->bus.prop;
>> +	prop->clk_freq = &amd_sdw_freq_tbl[0];
>> +	prop->mclk_freq = AMD_SDW_BUS_BASE_FREQ;
>> +
>> +	ret = sdw_bus_master_add(&amd_manager->bus, dev, dev->fwnode);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to register SoundWire manager(%d)\n", ret);
>> +		return ret;
>> +	}
>> +	dev_set_drvdata(dev, amd_manager);
>> +	INIT_WORK(&amd_manager->probe_work, amd_sdw_probe_work);
>> +	/*
>> +	 * Instead of having lengthy probe sequence, spilt probe in two and
> typo: split.
>
>> +	 * use work queue for SoundWire manager startup sequence.
> The wording 'startup' is confusing in that you do not have a startup
> sequence as for Intel. It's just deferred probe to avoid taking too much
> time.
will modify the comment.
>> +	 */
>> +	schedule_work(&amd_manager->probe_work);
>> +	return 0;
>> +}

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