Re: [PATCH 11/12] mci: arasan-sdhci: add HS200 tuning support on ZynqMP

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello Steffen,

On 08.03.24 12:17, Steffen Trumtrar wrote:
> The ZynpMP 8.9a has an Arasan IP core that supports HS200 tuning.
> Register the callback with the mci-core.
> 
> Arasan uses the SDHCI tuning method.
> 
> Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> ---
>  drivers/mci/arasan-sdhci.c | 62 +++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 59 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mci/arasan-sdhci.c b/drivers/mci/arasan-sdhci.c
> index 77ea1df7e7..c20d901c3f 100644
> --- a/drivers/mci/arasan-sdhci.c
> +++ b/drivers/mci/arasan-sdhci.c
> @@ -128,6 +128,46 @@ static int arasan_sdhci_reset(struct arasan_sdhci_host *host, u8 mask)
>  	return 0;
>  }
>  
> +static void arasan_zynqmp_dll_reset(struct arasan_sdhci_host *host, u32 deviceid)
> +{
> +	u16 clk;
> +
> +	clk = sdhci_read16(&host->sdhci, SDHCI_CLOCK_CONTROL);
> +	clk &= ~(SDHCI_CLOCK_CARD_EN | SDHCI_CLOCK_INT_EN);
> +	sdhci_write16(&host->sdhci, SDHCI_CLOCK_CONTROL, clk);
> +
> +	/* Issue DLL Reset */
> +	zynqmp_pm_sd_dll_reset(deviceid, PM_DLL_RESET_PULSE);
> +
> +	clk = sdhci_read16(&host->sdhci, SDHCI_CLOCK_CONTROL);
> +
> +	sdhci_enable_clk(&host->sdhci, clk);
> +}
> +
> +static int arasan_zynqmp_execute_tuning(struct mci_host *mci, u32 opcode)
> +{
> +	struct arasan_sdhci_host *host = to_arasan_sdhci_host(mci);
> +	struct clk_hw *hw = &host->clk_data.sdcardclk_hw;
> +	const char *clk_name = clk_hw_get_name(hw);
> +	u32 device_id = !strcmp(clk_name, "clk_out_sd0") ? NODE_SD_0 :
> +							   NODE_SD_1;
> +	int err;
> +
> +	/* ZynqMP SD controller does not perform auto tuning in DDR50 mode */
> +	if (mci->timing == MMC_TIMING_UHS_DDR50)
> +		return 0;
> +
> +	arasan_zynqmp_dll_reset(host, device_id);
> +
> +	err = sdhci_execute_tuning(&host->sdhci, opcode);
> +	if (err)
> +		return err;
> +
> +	arasan_zynqmp_dll_reset(host, device_id);
> +
> +	return 0;
> +}
> +
>  static int arasan_sdhci_init(struct mci_host *mci, struct device *dev)
>  {
>  	struct arasan_sdhci_host *host = to_arasan_sdhci_host(mci);
> @@ -226,8 +266,9 @@ static int arasan_sdhci_send_cmd(struct mci_host *mci, struct mci_cmd *cmd,
>  				cmd, data, false, &command, &xfer);
>  
>  	sdhci_write8(&host->sdhci, SDHCI_TIMEOUT_CONTROL, TIMEOUT_VAL);
> -	if (data) {
> +	if (xfer)
>  		sdhci_write16(&host->sdhci, SDHCI_TRANSFER_MODE, xfer);
> +	if (data) {
>  		sdhci_write16(&host->sdhci, SDHCI_BLOCK_SIZE,
>  			      SDHCI_DMA_BOUNDARY_512K | SDHCI_TRANSFER_BLOCK_SIZE(data->blocksize));
>  		sdhci_write16(&host->sdhci, SDHCI_BLOCK_COUNT, data->blocks);
> @@ -235,6 +276,10 @@ static int arasan_sdhci_send_cmd(struct mci_host *mci, struct mci_cmd *cmd,
>  	sdhci_write32(&host->sdhci, SDHCI_ARGUMENT, cmd->cmdarg);
>  	sdhci_write16(&host->sdhci, SDHCI_COMMAND, command);
>  
> +	/* CMD19/21 generate _only_ Buffer Read Ready interrupt */
> +	if (cmd->cmdidx == MMC_SEND_TUNING_BLOCK || cmd->cmdidx == MMC_SEND_TUNING_BLOCK_HS200)
> +		mask = SDHCI_INT_DATA_AVAIL;
> +
>  	ret = sdhci_wait_for_done(&host->sdhci, mask);
>  	if (ret)
>  		goto error;
> @@ -688,8 +733,11 @@ static int arasan_sdhci_probe(struct device *dev)
>  	if (of_property_read_bool(np, "no-1-8-v"))
>  		arasan_sdhci->quirks |= SDHCI_ARASAN_QUIRK_NO_1_8_V;
>  
> -	if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a"))
> +	if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a")) {
> +		if (IS_ENABLED(CONFIG_MCI_TUNING))
> +			mci->execute_tuning = arasan_zynqmp_execute_tuning;
>  		arasan_sdhci->quirks |= SDHCI_ARASAN_QUIRK_CLOCK_25_BROKEN;
> +	}
>  
>  	arasan_sdhci->sdhci.base = IOMEM(iores->start);
>  	arasan_sdhci->sdhci.mci = mci;
> @@ -700,7 +748,15 @@ static int arasan_sdhci_probe(struct device *dev)
>  	mci->card_write_protected = arasan_sdhci_card_write_protected;
>  	mci->hw_dev = dev;
>  
> -	mci->f_max = clk_get_rate(clk_xin);
> +	/*
> +	 * clk_rates on ZynqMP are rounded wrong. For HS200 clk_get_rate retunrs
> +	 * 199999998 instead of 200000000
> +	 */
> +	if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a"))
> +		mci->f_max = 200000000;
> +	else
> +		mci->f_max = clk_get_rate(clk_xin);
> +
>  	mci->f_min = 50000000 / 256;
>  
>  	arasan_sdhci_register_sdclk(&arasan_sdhci->clk_data, clk_xin, dev);
> 

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