RE: [PATCH v5 1/3] mmc: dw_mmc-bluefield: Add driver extension

[Liming Sun <lsun@mellanox.com>]

Please see response inline.

Thanks,
Liming

> -----Original Message-----
> From: Shawn Lin [mailto:shawn.lin@rock-chips.com]
> Sent: Tuesday, May 1, 2018 9:02 PM
> To: Liming Sun <lsun@mellanox.com>; Mark Rutland
> <mark.rutland@arm.com>; Jaehoon Chung <jh80.chung@samsung.com>;
> Catalin Marinas <catalin.marinas@arm.com>; Will Deacon
> <will.deacon@arm.com>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>; Rob Herring
> <robh+dt@kernel.org>; shawn.lin@rock-chips.com; linux-
> mmc@vger.kernel.org; devicetree@vger.kernel.org; linux-
> kernel@vger.kernel.org; stable@kernel.org
> Subject: Re: [PATCH v5 1/3] mmc: dw_mmc-bluefield: Add driver extension
> 
> On 2018/5/2 2:19, Liming Sun wrote:
> > This commit adds extension to the dw_mmc driver for Mellanox BlueField
> > SoC. It updates the UHS_REG_EXT register to bring up the eMMC card on
> > this SoC.
> >
> > Cc: stable@kernel.org
> 
> Why?

[Liming] This is recommended value from HW team. Without this setting, the eMMC 
controller and cards can be found in Linux, but not stable. Writing to it could caused
CRC error.

> 
> > Signed-off-by: Liming Sun <lsun@mellanox.com>
> > Reviewed-by: David Woods <dwoods@mellanox.com>
> > ---
> >   drivers/mmc/host/Kconfig            |  9 +++++
> >   drivers/mmc/host/Makefile           |  1 +
> >   drivers/mmc/host/dw_mmc-bluefield.c | 72
> +++++++++++++++++++++++++++++++++++++
> >   3 files changed, 82 insertions(+)
> >   create mode 100644 drivers/mmc/host/dw_mmc-bluefield.c
> >
> > diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> > index 9589f9c..26ac6b5 100644
> > --- a/drivers/mmc/host/Kconfig
> > +++ b/drivers/mmc/host/Kconfig
> > @@ -717,6 +717,15 @@ config MMC_DW_K3
> >   	  Synopsys DesignWare Memory Card Interface driver. Select this
> option
> >   	  for platforms based on Hisilicon K3 SoC's.
> >
> > +config MMC_DW_BLUEFIELD
> 
> And did you have feedback of my comment in V2？
> http://lists-archives.com/linux-kernel/29104830-mmc-dw_mmc-bluefield-
> add-driver-extension.html
> 
> > +	tristate "BlueField specific extensions for Synopsys DW Memory Card
> Interface"
> > +	depends on MMC_DW
> > +	select MMC_DW_PLTFM
> > +	help
> > +	  This selects support for Mellanox BlueField SoC specific extensions
> to
> > +	  the Synopsys DesignWare Memory Card Interface driver. Select this
> > +	  option for platforms based on Mellanox BlueField SoC's.
> > +
> >   config MMC_DW_PCI
> >   	tristate "Synopsys Designware MCI support on PCI bus"
> >   	depends on MMC_DW && PCI
> > diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> > index 6aead24..267b3f1 100644
> > --- a/drivers/mmc/host/Makefile
> > +++ b/drivers/mmc/host/Makefile
> > @@ -55,6 +55,7 @@ obj-$(CONFIG_MMC_DW_K3)		+= dw_mmc-
> k3.o
> >   obj-$(CONFIG_MMC_DW_PCI)	+= dw_mmc-pci.o
> >   obj-$(CONFIG_MMC_DW_ROCKCHIP)	+= dw_mmc-rockchip.o
> >   obj-$(CONFIG_MMC_DW_ZX)		+= dw_mmc-zx.o
> > +obj-$(CONFIG_MMC_DW_BLUEFIELD)	+= dw_mmc-bluefield.o
> >   obj-$(CONFIG_MMC_SH_MMCIF)	+= sh_mmcif.o
> >   obj-$(CONFIG_MMC_JZ4740)	+= jz4740_mmc.o
> >   obj-$(CONFIG_MMC_VUB300)	+= vub300.o
> > diff --git a/drivers/mmc/host/dw_mmc-bluefield.c
> b/drivers/mmc/host/dw_mmc-bluefield.c
> > new file mode 100644
> > index 0000000..12067b1
> > --- /dev/null
> > +++ b/drivers/mmc/host/dw_mmc-bluefield.c
> > @@ -0,0 +1,72 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2018 Mellanox Technologies.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/io.h>
> > +#include <linux/irq.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/mmc/host.h>
> > +#include <linux/mmc/mmc.h>
> > +#include <linux/of.h>
> > +
> > +#include "dw_mmc.h"
> > +#include "dw_mmc-pltfm.h"
> > +
> > +static void dw_mci_bluefield_set_ios(struct dw_mci *host, struct
> mmc_ios *ios)
> > +{
> > +	u32 regs;
> > +
> > +	/* Set drive=4 (bit 29:23) and sample=2 (bit 22:16) in UHS_REG_EXT.
> */
> > +	regs = mci_readl(host, UHS_REG_EXT);
> > +	regs = (regs & ~0x3F100000 & ~0x7F0000) | (4 << 23) | (2 << 16);
> > +	mci_writel(host, UHS_REG_EXT, regs);
> > +}
> > +
> > +static const struct dw_mci_drv_data bluefield_drv_data = {
> > +	.set_ios		= dw_mci_bluefield_set_ios
> > +};
> > +
> > +static const struct of_device_id dw_mci_bluefield_match[] = {
> > +	{ .compatible = "mellanox,bluefield-dw-mshc",
> > +		.data = &bluefield_drv_data },
> > +	{},
> > +};
> > +MODULE_DEVICE_TABLE(of, dw_mci_bluefield_match);
> > +
> > +static int dw_mci_bluefield_probe(struct platform_device *pdev)
> > +{
> > +	const struct dw_mci_drv_data *drv_data = NULL;
> > +	const struct of_device_id *match;
> > +
> > +	if (pdev->dev.of_node) {
> > +		match = of_match_node(dw_mci_bluefield_match,
> > +				      pdev->dev.of_node);
> > +		drv_data = match->data;
> > +	}
> > +
> > +	return dw_mci_pltfm_register(pdev, drv_data);
> > +}
> > +
> > +static struct platform_driver dw_mci_bluefield_pltfm_driver = {
> > +	.probe		= dw_mci_bluefield_probe,
> > +	.remove		= dw_mci_pltfm_remove,
> > +	.driver		= {
> > +		.name		= "dwmmc_bluefield",
> > +		.of_match_table	= dw_mci_bluefield_match,
> > +		.pm		= &dw_mci_pltfm_pmops,
> > +	},
> > +};
> > +
> > +module_platform_driver(dw_mci_bluefield_pltfm_driver);
> > +
> > +MODULE_DESCRIPTION("BlueField DW Multimedia Card driver");
> > +MODULE_AUTHOR("Mellanox Technologies");
> > +MODULE_LICENSE("GPL v2");
> >