linux/drivers/usb/host/ohci-at91.c
Alan Stern b5fb454f69 USB: automatically enable RHSC interrupts
This patch (as1069c) changes the way OHCI root-hub status-change
interrupts are enabled.  Currently a special HCD method,
hub_irq_enable(), is called when the hub driver is finished using a
root hub.  This approach turns out to be subject to races, resulting
in unnecessary polling.

The patch does away with the method entirely.  Instead, the driver
automatically enables the RHSC interrupt when no more status changes
are present.  This scheme is safe with controllers using
level-triggered semantics for their interrupt flags.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-08-21 10:26:38 -07:00

370 lines
8.2 KiB
C

/*
* OHCI HCD (Host Controller Driver) for USB.
*
* Copyright (C) 2004 SAN People (Pty) Ltd.
* Copyright (C) 2005 Thibaut VARENE <varenet@parisc-linux.org>
*
* AT91 Bus Glue
*
* Based on fragments of 2.4 driver by Rick Bronson.
* Based on ohci-omap.c
*
* This file is licenced under the GPL.
*/
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <mach/hardware.h>
#include <asm/gpio.h>
#include <mach/board.h>
#include <mach/cpu.h>
#ifndef CONFIG_ARCH_AT91
#error "CONFIG_ARCH_AT91 must be defined."
#endif
/* interface and function clocks; sometimes also an AHB clock */
static struct clk *iclk, *fclk, *hclk;
static int clocked;
extern int usb_disabled(void);
/*-------------------------------------------------------------------------*/
static void at91_start_clock(void)
{
if (cpu_is_at91sam9261())
clk_enable(hclk);
clk_enable(iclk);
clk_enable(fclk);
clocked = 1;
}
static void at91_stop_clock(void)
{
clk_disable(fclk);
clk_disable(iclk);
if (cpu_is_at91sam9261())
clk_disable(hclk);
clocked = 0;
}
static void at91_start_hc(struct platform_device *pdev)
{
struct usb_hcd *hcd = platform_get_drvdata(pdev);
struct ohci_regs __iomem *regs = hcd->regs;
dev_dbg(&pdev->dev, "start\n");
/*
* Start the USB clocks.
*/
at91_start_clock();
/*
* The USB host controller must remain in reset.
*/
writel(0, &regs->control);
}
static void at91_stop_hc(struct platform_device *pdev)
{
struct usb_hcd *hcd = platform_get_drvdata(pdev);
struct ohci_regs __iomem *regs = hcd->regs;
dev_dbg(&pdev->dev, "stop\n");
/*
* Put the USB host controller into reset.
*/
writel(0, &regs->control);
/*
* Stop the USB clocks.
*/
at91_stop_clock();
}
/*-------------------------------------------------------------------------*/
static void usb_hcd_at91_remove (struct usb_hcd *, struct platform_device *);
/* configure so an HC device and id are always provided */
/* always called with process context; sleeping is OK */
/**
* usb_hcd_at91_probe - initialize AT91-based HCDs
* Context: !in_interrupt()
*
* Allocates basic resources for this USB host controller, and
* then invokes the start() method for the HCD associated with it
* through the hotplug entry's driver_data.
*/
static int usb_hcd_at91_probe(const struct hc_driver *driver,
struct platform_device *pdev)
{
int retval;
struct usb_hcd *hcd = NULL;
if (pdev->num_resources != 2) {
pr_debug("hcd probe: invalid num_resources");
return -ENODEV;
}
if ((pdev->resource[0].flags != IORESOURCE_MEM)
|| (pdev->resource[1].flags != IORESOURCE_IRQ)) {
pr_debug("hcd probe: invalid resource type\n");
return -ENODEV;
}
hcd = usb_create_hcd(driver, &pdev->dev, "at91");
if (!hcd)
return -ENOMEM;
hcd->rsrc_start = pdev->resource[0].start;
hcd->rsrc_len = pdev->resource[0].end - pdev->resource[0].start + 1;
if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, hcd_name)) {
pr_debug("request_mem_region failed\n");
retval = -EBUSY;
goto err1;
}
hcd->regs = ioremap(hcd->rsrc_start, hcd->rsrc_len);
if (!hcd->regs) {
pr_debug("ioremap failed\n");
retval = -EIO;
goto err2;
}
iclk = clk_get(&pdev->dev, "ohci_clk");
fclk = clk_get(&pdev->dev, "uhpck");
if (cpu_is_at91sam9261())
hclk = clk_get(&pdev->dev, "hck0");
at91_start_hc(pdev);
ohci_hcd_init(hcd_to_ohci(hcd));
retval = usb_add_hcd(hcd, pdev->resource[1].start, IRQF_DISABLED);
if (retval == 0)
return retval;
/* Error handling */
at91_stop_hc(pdev);
if (cpu_is_at91sam9261())
clk_put(hclk);
clk_put(fclk);
clk_put(iclk);
iounmap(hcd->regs);
err2:
release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
err1:
usb_put_hcd(hcd);
return retval;
}
/* may be called with controller, bus, and devices active */
/**
* usb_hcd_at91_remove - shutdown processing for AT91-based HCDs
* @dev: USB Host Controller being removed
* Context: !in_interrupt()
*
* Reverses the effect of usb_hcd_at91_probe(), first invoking
* the HCD's stop() method. It is always called from a thread
* context, "rmmod" or something similar.
*
*/
static void usb_hcd_at91_remove(struct usb_hcd *hcd,
struct platform_device *pdev)
{
usb_remove_hcd(hcd);
at91_stop_hc(pdev);
iounmap(hcd->regs);
release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
usb_put_hcd(hcd);
if (cpu_is_at91sam9261())
clk_put(hclk);
clk_put(fclk);
clk_put(iclk);
fclk = iclk = hclk = NULL;
dev_set_drvdata(&pdev->dev, NULL);
}
/*-------------------------------------------------------------------------*/
static int __devinit
ohci_at91_start (struct usb_hcd *hcd)
{
struct at91_usbh_data *board = hcd->self.controller->platform_data;
struct ohci_hcd *ohci = hcd_to_ohci (hcd);
int ret;
if ((ret = ohci_init(ohci)) < 0)
return ret;
ohci->num_ports = board->ports;
if ((ret = ohci_run(ohci)) < 0) {
err("can't start %s", hcd->self.bus_name);
ohci_stop(hcd);
return ret;
}
return 0;
}
/*-------------------------------------------------------------------------*/
static const struct hc_driver ohci_at91_hc_driver = {
.description = hcd_name,
.product_desc = "AT91 OHCI",
.hcd_priv_size = sizeof(struct ohci_hcd),
/*
* generic hardware linkage
*/
.irq = ohci_irq,
.flags = HCD_USB11 | HCD_MEMORY,
/*
* basic lifecycle operations
*/
.start = ohci_at91_start,
.stop = ohci_stop,
.shutdown = ohci_shutdown,
/*
* managing i/o requests and associated device resources
*/
.urb_enqueue = ohci_urb_enqueue,
.urb_dequeue = ohci_urb_dequeue,
.endpoint_disable = ohci_endpoint_disable,
/*
* scheduling support
*/
.get_frame_number = ohci_get_frame,
/*
* root hub support
*/
.hub_status_data = ohci_hub_status_data,
.hub_control = ohci_hub_control,
#ifdef CONFIG_PM
.bus_suspend = ohci_bus_suspend,
.bus_resume = ohci_bus_resume,
#endif
.start_port_reset = ohci_start_port_reset,
};
/*-------------------------------------------------------------------------*/
static int ohci_hcd_at91_drv_probe(struct platform_device *pdev)
{
struct at91_usbh_data *pdata = pdev->dev.platform_data;
int i;
if (pdata) {
/* REVISIT make the driver support per-port power switching,
* and also overcurrent detection. Here we assume the ports
* are always powered while this driver is active, and use
* active-low power switches.
*/
for (i = 0; i < pdata->ports; i++) {
if (pdata->vbus_pin[i] <= 0)
continue;
gpio_request(pdata->vbus_pin[i], "ohci_vbus");
gpio_direction_output(pdata->vbus_pin[i], 0);
}
}
device_init_wakeup(&pdev->dev, 1);
return usb_hcd_at91_probe(&ohci_at91_hc_driver, pdev);
}
static int ohci_hcd_at91_drv_remove(struct platform_device *pdev)
{
struct at91_usbh_data *pdata = pdev->dev.platform_data;
int i;
if (pdata) {
for (i = 0; i < pdata->ports; i++) {
if (pdata->vbus_pin[i] <= 0)
continue;
gpio_direction_output(pdata->vbus_pin[i], 1);
gpio_free(pdata->vbus_pin[i]);
}
}
device_init_wakeup(&pdev->dev, 0);
usb_hcd_at91_remove(platform_get_drvdata(pdev), pdev);
return 0;
}
#ifdef CONFIG_PM
static int
ohci_hcd_at91_drv_suspend(struct platform_device *pdev, pm_message_t mesg)
{
struct usb_hcd *hcd = platform_get_drvdata(pdev);
struct ohci_hcd *ohci = hcd_to_ohci(hcd);
if (device_may_wakeup(&pdev->dev))
enable_irq_wake(hcd->irq);
/*
* The integrated transceivers seem unable to notice disconnect,
* reconnect, or wakeup without the 48 MHz clock active. so for
* correctness, always discard connection state (using reset).
*
* REVISIT: some boards will be able to turn VBUS off...
*/
if (at91_suspend_entering_slow_clock()) {
ohci_usb_reset (ohci);
at91_stop_clock();
}
return 0;
}
static int ohci_hcd_at91_drv_resume(struct platform_device *pdev)
{
struct usb_hcd *hcd = platform_get_drvdata(pdev);
if (device_may_wakeup(&pdev->dev))
disable_irq_wake(hcd->irq);
if (!clocked)
at91_start_clock();
ohci_finish_controller_resume(hcd);
return 0;
}
#else
#define ohci_hcd_at91_drv_suspend NULL
#define ohci_hcd_at91_drv_resume NULL
#endif
MODULE_ALIAS("platform:at91_ohci");
static struct platform_driver ohci_hcd_at91_driver = {
.probe = ohci_hcd_at91_drv_probe,
.remove = ohci_hcd_at91_drv_remove,
.shutdown = usb_hcd_platform_shutdown,
.suspend = ohci_hcd_at91_drv_suspend,
.resume = ohci_hcd_at91_drv_resume,
.driver = {
.name = "at91_ohci",
.owner = THIS_MODULE,
},
};