New patch to review for coreboot: 84b0f09 usbdebug: Halt host controller before resetting it

[Kyösti Mälkki]

Kyösti Mälkki ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3862

-gerrit

commit 84b0f09a4082c87b7cafeb8a67ce6a3c86f88498
Author: Kyösti Mälkki 
Date:   Mon Aug 12 15:32:25 2013 +0300

usbdebug: Halt host controller before resetting it

Resetting an EHCI controller when it is not halted can have
    undefined behaviour. This mostly fixes a case where calling
    usbdebug_init() twice would fail to reset the USB dongle device
    properly.

On amd/persimmon it still requires one extra retry, but at least it
    is now possible to have usbdebug enabled for both romstage and
    ramstage.

Change-Id: Ib0e6e5a0167404f68af2edf112306fdb8def0be9
    Signed-off-by: Kyösti Mälkki 
---
 src/lib/usbdebug.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/lib/usbdebug.c b/src/lib/usbdebug.c
index 81e78c6..c7c5520 100644
--- a/src/lib/usbdebug.c
+++ b/src/lib/usbdebug.c
@@ -449,6 +449,23 @@ try_next_port:
    	return -1;
    }

+	/* Wait until the controller is halted */
+	status = read32((unsigned long)&ehci_regs->status);
+	if (!(status & STS_HALT)) {
+		cmd = read32((unsigned long)&ehci_regs->command);
+		cmd &= ~CMD_RUN;
+		write32((unsigned long)&ehci_regs->command, cmd);
+		loop = 100;
+		do {
+			dbgp_mdelay(10);
+			status = read32((unsigned long)&ehci_regs->status);
+		} while (!(status & STS_HALT) && (--loop > 0));
+		if (status & STS_HALT)
+			dprintk(BIOS_INFO, "EHCI controller halted successfully.\n");
+		else
+			dprintk(BIOS_INFO, "EHCI controller is not halted. Reset may fail.\n");
+	}
+
    loop = 100;
    /* Reset the EHCI controller */
    cmd = read32((unsigned long)&ehci_regs->command);