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Commit 093344e1 authored by Jason Wessel's avatar Jason Wessel Committed by Greg Kroah-Hartman
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USB: ehci-dbgp: Execute early BIOS hand off 



The PCI quirk code executes a BIOS hand off to obtain full control of
the EHCI host controller, the self contained ehci-dbgp driver must do
the same thing using the early PCI API, else the BIOS can cause a
fatal fault.

Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: dbrownell@users.sourceforge.net
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 87a5d151

drivers/usb/early/ehci-dbgp.c

+49 −0
Original line number Diff line number Diff line
@@ -435,6 +435,53 @@ static void __init detect_set_debug_port(void) 
	}

}



/* The code in early_ehci_bios_handoff() is derived from the usb pci

 * quirk initialization, but altered so as to use the early PCI

 * routines. */

#define EHCI_USBLEGSUP_BIOS	(1 << 16)	/* BIOS semaphore */

#define EHCI_USBLEGCTLSTS	4		/* legacy control/status */

static void __init early_ehci_bios_handoff(void)

{

	u32 hcc_params = readl(&ehci_caps->hcc_params);

	int offset = (hcc_params >> 8) & 0xff;

	u32 cap;

	int msec;



	if (!offset)

		return;



	cap = read_pci_config(ehci_dev.bus, ehci_dev.slot,

			      ehci_dev.func, offset);

	dbgp_printk("dbgp: ehci BIOS state %08x\n", cap);



	if ((cap & 0xff) == 1 && (cap & EHCI_USBLEGSUP_BIOS)) {

		dbgp_printk("dbgp: BIOS handoff\n");

		write_pci_config_byte(ehci_dev.bus, ehci_dev.slot,

				      ehci_dev.func, offset + 3, 1);

	}



	/* if boot firmware now owns EHCI, spin till it hands it over. */

	msec = 1000;

	while ((cap & EHCI_USBLEGSUP_BIOS) && (msec > 0)) {

		mdelay(10);

		msec -= 10;

		cap = read_pci_config(ehci_dev.bus, ehci_dev.slot,

				      ehci_dev.func, offset);

	}



	if (cap & EHCI_USBLEGSUP_BIOS) {

		/* well, possibly buggy BIOS... try to shut it down,

		 * and hope nothing goes too wrong */

		dbgp_printk("dbgp: BIOS handoff failed: %08x\n", cap);

		write_pci_config_byte(ehci_dev.bus, ehci_dev.slot,

				      ehci_dev.func, offset + 2, 0);

	}



	/* just in case, always disable EHCI SMIs */

	write_pci_config_byte(ehci_dev.bus, ehci_dev.slot, ehci_dev.func,

			      offset + EHCI_USBLEGCTLSTS, 0);

}



static int __init ehci_setup(void)

{

	struct usb_debug_descriptor dbgp_desc;
@@ -446,6 +493,8 @@ static int __init ehci_setup(void) 
	int port_map_tried;

	int playtimes = 3;



	early_ehci_bios_handoff();



try_next_time:

	port_map_tried = 0;