Re: [PATCH v7][2/4] mmc: Add Synopsys DesignWare mmc cmdq host driver

Philipp Zabel
2023-11-27T12:51:55Z

Hi,

On Di, 2023-11-21 at 17:10 +0800, Jyan Chou wrote:
> We implemented cmdq feature on Synopsys DesignWare mmc driver.
> The difference between dw_mmc.c and dw_mmc_cqe.c were distinct
> register definitions, mmc user flow and the addition of cmdq.
>
> New version of User Guide had modify mmc driver's usage flow,
> we may need to renew code to precisely follow user guide.
>
> More over, We added a wait status function to satisfy synopsys
> user guide's description, since this flow might be specific in
> synopsys host driver only.
>
> Signed-off-by: Jyan Chou <jyanchou@realtek.com>
>
> —--
[...]
> diff --git a/drivers/mmc/host/dw_mmc_cqe.c b/drivers/mmc/host/dw_mmc_cqe.c
> new file mode 100644
> index 000000000000..eb00d6a474b2
> --- /dev/null
> +++ b/drivers/mmc/host/dw_mmc_cqe.c
> @@ -0,0 +1,1467 @@
[...]
> +#ifdef CONFIG_OF
> +static struct dw_mci_board *dw_mci_cqe_parse_dt(struct dw_mci *host)
> +{
> + struct dw_mci_board *pdata;
> + struct device *dev = host->dev;
> + const struct dw_mci_drv_data *drv_data = host->drv_data;
> + int ret;
> +
> + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> + if (!pdata)
> + return ERR_PTR(-ENOMEM);
> +
> + pdata->rstc = devm_reset_control_get_optional_exclusive(dev, NULL);
> + if (IS_ERR(pdata->rstc)) {
> + if (PTR_ERR(pdata->rstc) == -EPROBE_DEFER)
> + return ERR_PTR(-EPROBE_DEFER);

This should

return ERR_CAST(pdata->rstc);

instead.

There is no reason to hide device tree parsing errors here, and I'd
argue pdata should not be returned with rstc set to an error value.
devm_reset_control_get_optional_exclusive() returns NULL if there are
no errors and no reset is specified in the device tree.

Then you can just use dev_err_probe() at the call site in
dw_mci_cqe_probe().

[...]
> +int dw_mci_cqe_probe(struct dw_mci *host)
> +{
[...]
> + if (!IS_ERR(host->pdata->rstc)) {
> + reset_control_assert(host->pdata->rstc);
> + usleep_range(10, 50);
> + reset_control_deassert(host->pdata->rstc);
> + }

This should be changed to

if (host->pdata->rstc) {
reset_control_assert(host->pdata->rstc);
usleep_range(10, 50);
reset_control_deassert(host->pdata->rstc);
}

[...]
> + return 0;
> +
> +err_dmaunmap:
> + if (!IS_ERR(host->pdata->rstc))
> + reset_control_assert(host->pdata->rstc);

This should be just

reset_control_assert(host->pdata->rstc);

as reset_control_assert() is a no-op if host->pdata->rstc == NULL.

[...]
> +void dw_mci_cqe_remove(struct dw_mci *host)
> +{
[...]
> + if (!IS_ERR(host->pdata->rstc))
> + reset_control_assert(host->pdata->rstc);

reset_control_assert(host->pdata->rstc);

regards
Philipp