Re: [PATCH 17/28] mci: sdhci: atmel: extend driver for PBL usage

From: Sascha Hauer <s.hauer@pengutronix.de>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 17/28] mci: sdhci: atmel: extend driver for PBL usage
Date: Sun, 5 Jul 2020 20:52:52 +0200	[thread overview]
Message-ID: <20200705185252.GB15485@pengutronix.de> (raw)
In-Reply-To: <20200701091122.3437-18-a.fatoum@pengutronix.de>

On Wed, Jul 01, 2020 at 11:11:11AM +0200, Ahmad Fatoum wrote:
> The BootROM resets both the SD/MMC host controller and the pin controller,
> but the card itself remains in transfer mode. If we redo host-side
> setup, we can directly read new blocks off the card.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  drivers/mci/Kconfig              |   4 +
>  drivers/mci/Makefile             |   1 +
>  drivers/mci/atmel-sdhci-common.c |   3 +
>  drivers/mci/atmel-sdhci-pbl.c    | 128 +++++++++++++++++++++++++++++++
>  4 files changed, 136 insertions(+)
>  create mode 100644 drivers/mci/atmel-sdhci-pbl.c
> 
> diff --git a/drivers/mci/Kconfig b/drivers/mci/Kconfig
> index 6ae1e812528c..3026b25cadc9 100644
> --- a/drivers/mci/Kconfig
> +++ b/drivers/mci/Kconfig
> @@ -187,3 +187,7 @@ endif
>  config MCI_IMX_ESDHC_PBL
>  	bool
>  	select MCI_SDHCI
> +
> +config MCI_ATMEL_SDHCI_PBL
> +	bool
> +	select MCI_SDHCI
> diff --git a/drivers/mci/Makefile b/drivers/mci/Makefile
> index 177483dcfba5..4a5363367476 100644
> --- a/drivers/mci/Makefile
> +++ b/drivers/mci/Makefile
> @@ -5,6 +5,7 @@ obj-$(CONFIG_MCI_ATMEL_SDHCI)	+= atmel-sdhci.o atmel-sdhci-common.o
>  obj-$(CONFIG_MCI_BCM283X)	+= mci-bcm2835.o
>  obj-$(CONFIG_MCI_BCM283X_SDHOST)	+= bcm2835-sdhost.o
>  obj-$(CONFIG_MCI_DOVE)		+= dove-sdhci.o
> +pbl-$(CONFIG_MCI_ATMEL_SDHCI_PBL)	+= atmel-sdhci-pbl.o atmel-sdhci-common.o
>  obj-$(CONFIG_MCI_IMX)		+= imx.o
>  obj-$(CONFIG_MCI_IMX_ESDHC)	+= imx-esdhc.o imx-esdhc-common.o
>  pbl-$(CONFIG_MCI_IMX_ESDHC_PBL)	+= imx-esdhc-pbl.o imx-esdhc-common.o
> diff --git a/drivers/mci/atmel-sdhci-common.c b/drivers/mci/atmel-sdhci-common.c
> index 1884f3836337..a83610c3d090 100644
> --- a/drivers/mci/atmel-sdhci-common.c
> +++ b/drivers/mci/atmel-sdhci-common.c
> @@ -12,7 +12,10 @@
>  #include <common.h>
>  #include <mci.h>
>  
> +#include <mach/early_udelay.h>
> +
>  #ifdef __PBL__
> +#define udelay early_udelay
>  #undef  dev_err
>  #define dev_err(d, ...)		pr_err(__VA_ARGS__)
>  #undef  dev_warn
> diff --git a/drivers/mci/atmel-sdhci-pbl.c b/drivers/mci/atmel-sdhci-pbl.c
> new file mode 100644
> index 000000000000..626e4008fe85
> --- /dev/null
> +++ b/drivers/mci/atmel-sdhci-pbl.c
> @@ -0,0 +1,128 @@
> +// SPDX-License-Identifier: BSD-1-Clause
> +/*
> + * Copyright (c) 2015, Atmel Corporation
> + * Copyright (c) 2019, Ahmad Fatoum, Pengutronix
> + *
> + * Atmel's name may not be used to endorse or promote products derived from
> + * this software without specific prior written permission.
> + */
> +
> +#include <common.h>
> +#include <pbl.h>
> +#include <mci.h>
> +#include <debug_ll.h>
> +#include <mach/xload.h>
> +#include "atmel-sdhci.h"
> +
> +#include <mach/early_udelay.h>
> +
> +#ifdef __PBL__
> +#define udelay early_udelay
> +#endif
> +
> +#define SECTOR_SIZE			512
> +#define SUPPORT_MAX_BLOCKS		16U
> +
> +struct at91_sdhci_priv {
> +	struct at91_sdhci host;
> +	bool highcapacity_card;
> +};
> +
> +static int sd_cmd_stop_transmission(struct at91_sdhci_priv *priv)
> +{
> +	struct mci_cmd cmd = {
> +		.cmdidx = MMC_CMD_STOP_TRANSMISSION,
> +		.resp_type = MMC_RSP_R1b,
> +	};
> +
> +	return at91_sdhci_send_command(&priv->host, &cmd, NULL);
> +}
> +
> +static int sd_cmd_read_multiple_block(struct at91_sdhci_priv *priv,
> +				      void *buf,
> +				      unsigned int start,
> +				      unsigned int block_count)
> +{
> +	u16 block_len = SECTOR_SIZE;
> +	struct mci_data data;
> +	struct mci_cmd cmd = {
> +		.cmdidx = MMC_CMD_READ_MULTIPLE_BLOCK,
> +		.resp_type = MMC_RSP_R1,
> +		.cmdarg = start,
> +	};
> +
> +	if (!priv->highcapacity_card)
> +		cmd.cmdarg *= block_len;
> +
> +	data.dest = buf;
> +	data.flags = MMC_DATA_READ;
> +	data.blocksize = block_len;
> +	data.blocks = block_count;
> +
> +	return at91_sdhci_send_command(&priv->host, &cmd, &data);
> +}
> +
> +static int at91_sdhci_bio_read(struct pbl_bio *bio, off_t start,
> +				void *buf, unsigned int nblocks)
> +{
> +	struct at91_sdhci_priv *priv = bio->priv;
> +	unsigned int blocks_done = 0;
> +	unsigned int blocks;
> +	unsigned int block_len = SECTOR_SIZE;
> +	unsigned int blocks_read;
> +	int ret;
> +
> +	/*
> +	 * Refer to the at91sam9g20 datasheet:
> +	 * Figure 35-10. Read Function Flow Diagram
> +	*/
> +
> +	while (blocks_done < nblocks) {
> +		blocks = min(nblocks - blocks_done, SUPPORT_MAX_BLOCKS);
> +
> +		blocks_read = sd_cmd_read_multiple_block(priv, buf,
> +							 start + blocks_done,
> +							 blocks);
> +
> +		ret = sd_cmd_stop_transmission(priv);
> +		if (ret)
> +			return ret;
> +
> +		blocks_done += blocks_read;
> +
> +		if (blocks_read != blocks)
> +			break;
> +
> +		buf += blocks * block_len;
> +	}
> +
> +	return blocks_done;
> +}

All this doesn't look at91 specific. It rather looks like it could be
generic code. I know I have put similar code into the i.MX esdhc PBL
driver, so I can't complain very much...

Sascha

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