Subject: [PATCH 2/8] usb: host: xhci-plat: Add support for the Armada 38x glue code

From: [email-masked] (Gregory CLEMENT)
Date: Wed, 23 Apr 2014 09:44:57 +0200

Hi Felipe,

On 20/04/2014 05:20, Felipe Balbi wrote:
> On Fri, Apr 18, 2014 at 12:22:37PM +0200, Gregory CLEMENT wrote:
>> For the armada 38x SoCs which come with an xhci controller, specific
>> initialization must be done during probe, especially in relation with
>> the MBus windows initialization. This patch adds this support.
>>
>> Signed-off-by: Gregory CLEMENT <[email-masked]>
>> ---
>>  drivers/usb/host/Kconfig      |   7 +++
>>  drivers/usb/host/Makefile     |   1 +
>>  drivers/usb/host/xhci-mvebu.c | 105 ++++++++++++++++++++++++++++++++++++++++++
>>  drivers/usb/host/xhci-mvebu.h |  21 +++++++++
>>  drivers/usb/host/xhci-plat.c  |  10 ++++
>>  5 files changed, 144 insertions(+)
>>  create mode 100644 drivers/usb/host/xhci-mvebu.c
>>  create mode 100644 drivers/usb/host/xhci-mvebu.h
>>
>> diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
>> index 3d9e54062d62..e70943fac4a1 100644
>> --- a/drivers/usb/host/Kconfig
>> +++ b/drivers/usb/host/Kconfig
>> @@ -29,6 +29,13 @@ if USB_XHCI_HCD
>>  config USB_XHCI_PLATFORM
>>  	tristate
>>  
>> +config USB_XHCI_MVEBU
>> +	tristate "xHCI support for Marvell Armada 38x"
>> +	select USB_XHCI_PLATFORM
>> +	---help---
>> +	  Say 'Y' to enable the support for the xHCI host controller
>> +	  found in Marvell Armada 38x ARM SOCs.
>> +
>>  endif # USB_XHCI_HCD
>>  
>>  config USB_EHCI_HCD
>> diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
>> index 7530468c9a4f..7a8db7f7dc01 100644
>> --- a/drivers/usb/host/Makefile
>> +++ b/drivers/usb/host/Makefile
>> @@ -19,6 +19,7 @@ xhci-hcd-$(CONFIG_PCI)	+= xhci-pci.o
>>  
>>  ifneq ($(CONFIG_USB_XHCI_PLATFORM), )
>>  	xhci-hcd-y		+= xhci-plat.o
>> +	xhci-hcd-$(CONFIG_USB_XHCI_MVEBU)	+= xhci-mvebu.o
>>  endif
>>  
>>  obj-$(CONFIG_USB_WHCI_HCD)	+= whci/
>> diff --git a/drivers/usb/host/xhci-mvebu.c b/drivers/usb/host/xhci-mvebu.c
>> new file mode 100644
>> index 000000000000..dc9c7648ab65
>> --- /dev/null
>> +++ b/drivers/usb/host/xhci-mvebu.c
>> @@ -0,0 +1,105 @@
>> +/*
>> + * Copyright (C) 2014 Marvell
>> + * Author: Gregory CLEMENT <[email-masked]>
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License
>> + * version 2 as published by the Free Software Foundation.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/io.h>
>> +#include <linux/mbus.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +
>> +#include "xhci.h"
>> +
>> +#define USB3_MAX_WINDOWS	4
>> +#define USB3_WIN_CTRL(w)	(0x0 + ((w) * 8))
>> +#define USB3_WIN_BASE(w)	(0x4 + ((w) * 8))
>> +
>> +static void __init mv_usb3_conf_mbus_windows(void __iomem *base,
>> +			const struct mbus_dram_target_info *dram)
>> +{
>> +	int win;
>> +
>> +	/* Clear all existing windows */
>> +	for (win = 0; win < USB3_MAX_WINDOWS; win++) {
>> +		writel(0, base + USB3_WIN_CTRL(win));
>> +		writel(0, base + USB3_WIN_BASE(win));
>> +	}
>> +
>> +	/* Program each DRAM CS in a seperate window */
>> +	for (win = 0; win < dram->num_cs; win++) {
>> +		const struct mbus_dram_window *cs = dram->cs + win;
>> +
>> +		writel(((cs->size - 1) & 0xffff0000) | (cs->mbus_attr << 8) |
>> +		       (dram->mbus_dram_target_id << 4) | 1,
>> +		       base + USB3_WIN_CTRL(win));
>> +
>> +		writel((cs->base & 0xffff0000), base + USB3_WIN_BASE(win));
>> +	}
>> +}
>> +
>> +int xhci_mvebu_probe(struct platform_device *pdev)
>> +{
>> +	struct resource	*res;
>> +	void __iomem	*base;
>> +	const struct mbus_dram_target_info *dram;
>> +	int ret;
>> +	struct clk *clk;
>> +
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
>> +	if (!res)
>> +		return -ENODEV;
>> +
>> +	/*
>> +	 * We don't use devm_ioremap() because this mapping should
>> +	 * only exists for the duration of this probe function.
>> +	 */
>> +	base = ioremap(res->start, resource_size(res));
>> +	if (!base)
>> +		return -ENODEV;
>> +
>> +	clk = devm_clk_get(&pdev->dev, NULL);
>> +	if (IS_ERR(clk)) {
>> +		iounmap(base);
>> +		return PTR_ERR(clk);
>> +	}
>> +
>> +	ret = clk_prepare_enable(clk);
>> +	if (ret < 0) {
>> +		iounmap(base);
>> +		return ret;
>> +	}
> 
> it's best to teach generic xhci-plat about clocks, just make it
> optional.

OK

> 
>> +	dram = mv_mbus_dram_info();
>> +	mv_usb3_conf_mbus_windows(base, dram);
>> +
>> +	/*
>> +	 * This memory area was only needed to configure the MBus
>> +	 * windows, and is therefore no longer useful.
>> +	 */
>> +	iounmap(base);
> 
> so I suppose MBus is the Marvell interconnect, am I right ? Wouldn't you
> be duplicating this sort of initialization for most drivers ?

Actually most of them don't need it.

> 
>> +	ret = common_xhci_plat_probe(pdev, clk);
> 
> I would much rather reverse this, instead of exposing xhci-plat's probe,
> turn this mbus initialization into a quirk which will ioremap the extra
> resource, initialize some registers and iounmap it.

This approach have been inspired by what have been done for SDHCI and AHCI.
The infrastructure allowing adding platform code is in the generic file but
all the specific code is in the platform file.

But if for USB you think we should do it in a different way, I will do it.

Thanks for your review

Gregory

> 
>> diff --git a/drivers/usb/host/xhci-mvebu.h b/drivers/usb/host/xhci-mvebu.h
>> new file mode 100644
>> index 000000000000..897ef298f22f
>> --- /dev/null
>> +++ b/drivers/usb/host/xhci-mvebu.h
>> @@ -0,0 +1,21 @@
>> +/*
>> + * Copyright (C) 2014 Marvell
>> + *
>> + * Gregory Clement <[email-masked]>
>> + *
>> + * This file is licensed under the terms of the GNU General Public
>> + * License version 2.  This program is licensed "as is" without any
>> + * warranty of any kind, whether express or implied.
>> + */
>> +
>> +#ifndef __LINUX_XHCI_MVEBU_H
>> +#define __LINUX_XHCI_MVEBU_H
>> +
>> +#ifdef CONFIG_USB_XHCI_MVEBU
>> +int xhci_mvebu_probe(struct platform_device *pdev);
>> +int xhci_mvebu_remove(struct platform_device *pdev);
>> +#else
>> +#define xhci_mvebu_probe NULL
>> +#define xhci_mvebu_remove NULL
>> +#endif
>> +#endif /* __LINUX_XHCI_MVEBU_H */
>> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
>> index 8029cc82edc4..f1261d3848a9 100644
>> --- a/drivers/usb/host/xhci-plat.c
>> +++ b/drivers/usb/host/xhci-plat.c
>> @@ -19,6 +19,7 @@
>>  #include <linux/of_device.h>
>>  
>>  #include "xhci.h"
>> +#include "xhci-mvebu.h"
>>  
>>  static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
>>  {
>> @@ -250,6 +251,11 @@ static const struct dev_pm_ops xhci_plat_pm_ops = {
>>  #endif /* CONFIG_PM */
>>  
>>  #ifdef CONFIG_OF
>> +struct xhci_plat_ops xhci_plat_mvebu = {
>> +	.probe =  xhci_mvebu_probe,
>> +	.remove =  xhci_mvebu_remove,
>> +};
> 
> instead, just pass a flag such as:
> 
> XHCI_PLAT_MVEBU_MBUS_INIT_QUIRK or something
> 

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com