Message-ID: <3fc73b5d-1de7-41bb-b9ca-2878f311c6fc@kernel.org>
Date: Fri, 5 Dec 2025 08:51:12 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Jeff Chen <jeff.chen_1@....com>, linux-wireless@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, briannorris@...omium.org,
 johannes@...solutions.net, francesco@...cini.it, tsung-hsien.hsieh@....com,
 s.hauer@...gutronix.de
Subject: Re: [PATCH v8 19/22] wifi: nxpwifi: add initial SDIO bus driver
 support

On 05/12/2025 07:55, Jeff Chen wrote:
> +static const struct of_device_id nxpwifi_sdio_of_match_table[] __maybe_unused = {
> +	{ .compatible = "nxp,iw61x" },
> +	{ }
> +};
> +
> +/*
> + * This function parse device tree node using mmc subnode devicetree API.
> + * The device node is saved in card->plt_of_node.
> + * if the device tree node exist and include interrupts attributes, this
> + * function will also request platform specific wakeup interrupt.
> + */
> +static int nxpwifi_sdio_probe_of(struct device *dev)
> +{
> +	if (!of_match_node(nxpwifi_sdio_of_match_table, dev->of_node)) {
> +		dev_err(dev, "required compatible string missing\n");

What? How did you probe otherwise?

> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +/*
> + * SDIO probe.
> + *
> + * This function probes an nxpwifi device and registers it. It allocates
> + * the card structure, enables SDIO function number and initiates the
> + * device registration and initialization procedure by adding a logical
> + * interface.
> + */
> +static int
> +nxpwifi_sdio_probe(struct sdio_func *func, const struct sdio_device_id *id)
> +{
> +	int ret;
> +	struct sdio_mmc_card *card = NULL;
> +
> +	pr_debug("info: vendor=0x%4.04X device=0x%4.04X class=%d function=%d\n",
> +		 func->vendor, func->device, func->class, func->num);

NAK. Don't post such code. Look how drivers are supposed to use debug
functions.

And entrance to probe IS NEVER, NEVER debugged.

> +
> +	card = devm_kzalloc(&func->dev, sizeof(*card), GFP_KERNEL);
> +	if (!card)
> +		return -ENOMEM;
> +
> +	init_completion(&card->fw_done);
> +
> +	card->func = func;
> +
> +	func->card->quirks |= MMC_QUIRK_BLKSZ_FOR_BYTE_MODE;
> +
> +	if (id->driver_data) {
> +		struct nxpwifi_sdio_device *data = (void *)id->driver_data;
> +
> +		card->firmware = data->firmware;
> +		card->firmware_sdiouart = data->firmware_sdiouart;
> +		card->reg = data->reg;
> +		card->max_ports = data->max_ports;
> +		card->mp_agg_pkt_limit = data->mp_agg_pkt_limit;
> +		card->tx_buf_size = data->tx_buf_size;
> +		card->mp_tx_agg_buf_size = data->mp_tx_agg_buf_size;
> +		card->mp_rx_agg_buf_size = data->mp_rx_agg_buf_size;
> +		card->can_dump_fw = data->can_dump_fw;
> +		card->fw_dump_enh = data->fw_dump_enh;
> +		card->can_ext_scan = data->can_ext_scan;
> +		INIT_WORK(&card->work, nxpwifi_sdio_work);
> +	}
> +
> +	sdio_claim_host(func);
> +	ret = sdio_enable_func(func);
> +	sdio_release_host(func);
> +
> +	if (ret) {
> +		dev_err(&func->dev, "failed to enable function\n");
> +		return ret;
> +	}
> +
> +	/* device tree node parsing and platform specific configuration*/
> +	if (func->dev.of_node) {
> +		ret = nxpwifi_sdio_probe_of(&func->dev);
> +		if (ret)
> +			goto err_disable;
> +	}
> +
> +	ret = nxpwifi_add_card(card, &card->fw_done, &sdio_ops,
> +			       NXPWIFI_SDIO, &func->dev);
> +	if (ret) {
> +		dev_err(&func->dev, "add card failed\n");
> +		goto err_disable;
> +	}
> +
> +	return 0;
> +
> +err_disable:
> +	sdio_claim_host(func);
> +	sdio_disable_func(func);
> +	sdio_release_host(func);
> +
> +	return ret;
> +}
> +
> +/*
> + * SDIO resume.
> + *
> + * Kernel needs to suspend all functions separately. Therefore all
> + * registered functions must have drivers with suspend and resume
> + * methods. Failing that the kernel simply removes the whole card.
> + *
> + * If already not resumed, this function turns on the traffic and
> + * sends a host sleep cancel request to the firmware.
> + */
> +static int nxpwifi_sdio_resume(struct device *dev)
> +{
> +	struct sdio_func *func = dev_to_sdio_func(dev);
> +	struct sdio_mmc_card *card;
> +	struct nxpwifi_adapter *adapter;
> +
> +	card = sdio_get_drvdata(func);
> +	if (!card || !card->adapter) {
> +		nxpwifi_dbg(adapter, ERROR, "resume: invalid card or adapter\n");
> +		return 0;
> +	}
> +
> +	adapter = card->adapter;
> +
> +	if (!test_bit(NXPWIFI_IS_SUSPENDED, &adapter->work_flags)) {
> +		nxpwifi_dbg(adapter, WARN,
> +			    "device already resumed\n");
> +		return 0;
> +	}
> +
> +	clear_bit(NXPWIFI_IS_SUSPENDED, &adapter->work_flags);
> +
> +	/* Disable Host Sleep */
> +	nxpwifi_cancel_hs(nxpwifi_get_priv(adapter, NXPWIFI_BSS_ROLE_STA),
> +			  NXPWIFI_SYNC_CMD);
> +
> +	nxpwifi_disable_wake(adapter);
> +
> +	return 0;
> +}
> +
> +/* Write data into SDIO card register. Caller claims SDIO device. */
> +static int
> +nxpwifi_write_reg_locked(struct sdio_func *func, u32 reg, u8 data)
> +{
> +	int ret;
> +
> +	sdio_writeb(func, data, reg, &ret);
> +	return ret;
> +}
> +
> +/* This function writes data into SDIO card register.
> + */
> +static int
> +nxpwifi_write_reg(struct nxpwifi_adapter *adapter, u32 reg, u8 data)
> +{
> +	struct sdio_mmc_card *card = adapter->card;
> +	int ret;
> +
> +	sdio_claim_host(card->func);
> +	ret = nxpwifi_write_reg_locked(card->func, reg, data);
> +	sdio_release_host(card->func);
> +
> +	return ret;
> +}
> +
> +/* This function reads data from SDIO card register.
> + */
> +static int
> +nxpwifi_read_reg(struct nxpwifi_adapter *adapter, u32 reg, u8 *data)
> +{
> +	struct sdio_mmc_card *card = adapter->card;
> +	int ret;
> +	u8 val;
> +
> +	sdio_claim_host(card->func);
> +	val = sdio_readb(card->func, reg, &ret);
> +	sdio_release_host(card->func);
> +
> +	*data = val;
> +
> +	return ret;
> +}
> +
> +/*
> + * This function writes multiple data into SDIO card memory.
> + *
> + * This does not work in suspended mode.
> + */
> +static int
> +nxpwifi_write_data_sync(struct nxpwifi_adapter *adapter,
> +			u8 *buffer, u32 pkt_len, u32 port)
> +{
> +	struct sdio_mmc_card *card = adapter->card;
> +	int ret;
> +	u8 blk_mode =
> +		(port & NXPWIFI_SDIO_BYTE_MODE_MASK) ? BYTE_MODE : BLOCK_MODE;
> +	u32 blk_size = (blk_mode == BLOCK_MODE) ? NXPWIFI_SDIO_BLOCK_SIZE : 1;
> +	u32 blk_cnt =
> +		(blk_mode ==
> +		 BLOCK_MODE) ? (pkt_len /
> +				NXPWIFI_SDIO_BLOCK_SIZE) : pkt_len;
> +	u32 ioport = (port & NXPWIFI_SDIO_IO_PORT_MASK);
> +
> +	if (test_bit(NXPWIFI_IS_SUSPENDED, &adapter->work_flags)) {
> +		nxpwifi_dbg(adapter, ERROR,
> +			    "%s: not allowed while suspended\n", __func__);
> +		return -EPERM;
> +	}
> +
> +	sdio_claim_host(card->func);
> +
> +	ret = sdio_writesb(card->func, ioport, buffer, blk_cnt * blk_size);
> +
> +	sdio_release_host(card->func);
> +
> +	return ret;
> +}
> +
> +/* This function reads multiple data from SDIO card memory.
> + */
> +static int nxpwifi_read_data_sync(struct nxpwifi_adapter *adapter, u8 *buffer,
> +				  u32 len, u32 port, u8 claim)
> +{
> +	struct sdio_mmc_card *card = adapter->card;
> +	int ret;
> +	u8 blk_mode = (port & NXPWIFI_SDIO_BYTE_MODE_MASK) ? BYTE_MODE
> +		       : BLOCK_MODE;
> +	u32 blk_size = (blk_mode == BLOCK_MODE) ? NXPWIFI_SDIO_BLOCK_SIZE : 1;
> +	u32 blk_cnt = (blk_mode == BLOCK_MODE) ? (len / NXPWIFI_SDIO_BLOCK_SIZE)
> +			: len;
> +	u32 ioport = (port & NXPWIFI_SDIO_IO_PORT_MASK);
> +
> +	if (claim)
> +		sdio_claim_host(card->func);
> +
> +	ret = sdio_readsb(card->func, buffer, ioport, blk_cnt * blk_size);
> +
> +	if (claim)
> +		sdio_release_host(card->func);
> +
> +	return ret;
> +}
> +
> +/* This function reads the firmware status.
> + */
> +static int
> +nxpwifi_sdio_read_fw_status(struct nxpwifi_adapter *adapter, u16 *dat)
> +{
> +	struct sdio_mmc_card *card = adapter->card;
> +	const struct nxpwifi_sdio_card_reg *reg = card->reg;
> +	u8 fws0, fws1;
> +	int ret;
> +
> +	ret = nxpwifi_read_reg(adapter, reg->status_reg_0, &fws0);
> +	if (ret)
> +		return ret;
> +
> +	ret = nxpwifi_read_reg(adapter, reg->status_reg_1, &fws1);
> +	if (ret)
> +		return ret;
> +
> +	*dat = (u16)((fws1 << 8) | fws0);
> +	return ret;
> +}
> +
> +/* This function checks the firmware status in card.
> + */
> +static int nxpwifi_check_fw_status(struct nxpwifi_adapter *adapter,
> +				   u32 poll_num)
> +{
> +	int ret = 0;
> +	u16 firmware_stat = 0;
> +	u32 tries;
> +
> +	for (tries = 0; tries < poll_num; tries++) {
> +		ret = nxpwifi_sdio_read_fw_status(adapter, &firmware_stat);
> +		if (ret)
> +			continue;
> +		if (firmware_stat == FIRMWARE_READY_SDIO) {
> +			ret = 0;
> +			break;
> +		}
> +
> +		msleep(100);
> +		ret = -EPERM;
> +	}
> +
> +	if (firmware_stat == FIRMWARE_READY_SDIO)
> +		/*
> +		 * firmware might pretend to be ready, when it's not.
> +		 * Wait a little bit more as a workaround.
> +		 */
> +		msleep(100);
> +
> +	return ret;
> +}
> +
> +/* This function checks if WLAN is the winner.
> + */
> +static int nxpwifi_check_winner_status(struct nxpwifi_adapter *adapter)
> +{
> +	int ret;
> +	u8 winner = 0;
> +	struct sdio_mmc_card *card = adapter->card;
> +
> +	ret = nxpwifi_read_reg(adapter, card->reg->status_reg_0, &winner);
> +	if (ret)
> +		return ret;
> +
> +	if (winner)
> +		adapter->winner = 0;
> +	else
> +		adapter->winner = 1;
> +
> +	return ret;
> +}
> +
> +/*
> + * SDIO remove.
> + *
> + * This function removes the interface and frees up the card structure.
> + */
> +static void
> +nxpwifi_sdio_remove(struct sdio_func *func)
> +{
> +	struct sdio_mmc_card *card;
> +	struct nxpwifi_adapter *adapter;
> +	struct nxpwifi_private *priv;
> +	int ret = 0;
> +	u16 firmware_stat;
> +
> +	card = sdio_get_drvdata(func);
> +	if (!card)
> +		return;
> +
> +	wait_for_completion(&card->fw_done);
> +
> +	adapter = card->adapter;
> +	if (!adapter || !adapter->priv_num)
> +		return;
> +
> +	nxpwifi_dbg(adapter, INFO, "info: SDIO func num=%d\n", func->num);

This does not look like useful printk message. Drivers should be silent
on success:
https://elixir.bootlin.com/linux/v6.15-rc7/source/Documentation/process/coding-style.rst#L913
https://elixir.bootlin.com/linux/v6.15-rc7/source/Documentation/process/debugging/driver_development_debugging_guide.rst#L79

Debug messages for entry/exit are really useless.

> +



> +
> +static struct sdio_driver nxpwifi_sdio = {
> +	.name = "nxpwifi_sdio",
> +	.id_table = nxpwifi_ids,
> +	.probe = nxpwifi_sdio_probe,
> +	.remove = nxpwifi_sdio_remove,
> +	.drv = {
> +		.owner = THIS_MODULE,

Why are you upstreaming 12-13 years old code?

No, drop all this old stuff and create your code from the scratch, based
on latest reviewed driver. Otherwise you just duplicated all issues we
fixed past 12 years!

> +		.coredump = nxpwifi_sdio_coredump,
> +		.pm = &nxpwifi_sdio_pm_ops,
> +	}
> +};
> +
> +/*
> + * This function wakes up the card.

Really usesless way of commenting code. Can you look at existing source
code to learn how comments are supposed to be written?


Best regards,
Krzysztof

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