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linux-next/drivers/usb/dwc2/core_intr.c
Douglas Anderson 29539019b4 usb: dwc2: host: Clear interrupts before handling them 
In general it is wise to clear interrupts before processing them.  If
you don't do that, you can get:
 1. Interrupt happens
 2. You look at system state and process interrupt
 3. A new interrupt happens
 4. You clear interrupt without processing it.

This patch was actually a first attempt to fix missing device insertions
as described in (usb: dwc2: host: Fix missing device insertions) and it
did solve some of the signal bouncing problems but not all of
them (which is why I submitted the other patch).  Specifically, this
patch itself would sometimes change:
 1. hardware sees connect
 2. hardware sees disconnect
 3. hardware sees connect
 4. dwc2_port_intr() - clears connect interrupt
 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect()

...to:
 1. hardware sees connect
 2. hardware sees disconnect
 3. dwc2_port_intr() - clears connect interrupt
 4. hardware sees connect
 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect()

...but with different timing then sometimes we'd still miss cable
insertions.

In any case, though this patch doesn't fix any (known) problems, it
still seems wise as a general policy to clear interrupt before handling
them.

Note that for dwc2_handle_usb_port_intr(), instead of moving the clear
of PRTINT to the beginning of the function we remove it completely.  The
only way to clear PRTINT is to clear the sources that set it in the
first place.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
2015-12-15 09:12:41 -06:00

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/*
* core_intr.c - DesignWare HS OTG Controller common interrupt handling
*
* Copyright (C) 2004-2013 Synopsys, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The names of the above-listed copyright holders may not be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* ALTERNATIVELY, this software may be distributed under the terms of the
* GNU General Public License ("GPL") as published by the Free Software
* Foundation; either version 2 of the License, or (at your option) any
* later version.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* This file contains the common interrupt handlers
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <linux/usb/ch11.h>
#include "core.h"
#include "hcd.h"
static const char *dwc2_op_state_str(struct dwc2_hsotg *hsotg)
{
switch (hsotg->op_state) {
case OTG_STATE_A_HOST:
return "a_host";
case OTG_STATE_A_SUSPEND:
return "a_suspend";
case OTG_STATE_A_PERIPHERAL:
return "a_peripheral";
case OTG_STATE_B_PERIPHERAL:
return "b_peripheral";
case OTG_STATE_B_HOST:
return "b_host";
default:
return "unknown";
}
}
/**
* dwc2_handle_usb_port_intr - handles OTG PRTINT interrupts.
* When the PRTINT interrupt fires, there are certain status bits in the Host
* Port that needs to get cleared.
*
* @hsotg: Programming view of DWC_otg controller
*/
static void dwc2_handle_usb_port_intr(struct dwc2_hsotg *hsotg)
{
u32 hprt0 = dwc2_readl(hsotg->regs + HPRT0);
if (hprt0 & HPRT0_ENACHG) {
hprt0 &= ~HPRT0_ENA;
dwc2_writel(hprt0, hsotg->regs + HPRT0);
}
}
/**
* dwc2_handle_mode_mismatch_intr() - Logs a mode mismatch warning message
*
* @hsotg: Programming view of DWC_otg controller
*/
static void dwc2_handle_mode_mismatch_intr(struct dwc2_hsotg *hsotg)
{
/* Clear interrupt */
dwc2_writel(GINTSTS_MODEMIS, hsotg->regs + GINTSTS);
dev_warn(hsotg->dev, "Mode Mismatch Interrupt: currently in %s mode\n",
dwc2_is_host_mode(hsotg) ? "Host" : "Device");
}
/**
* dwc2_handle_otg_intr() - Handles the OTG Interrupts. It reads the OTG
* Interrupt Register (GOTGINT) to determine what interrupt has occurred.
*
* @hsotg: Programming view of DWC_otg controller
*/
static void dwc2_handle_otg_intr(struct dwc2_hsotg *hsotg)
{
u32 gotgint;
u32 gotgctl;
u32 gintmsk;
gotgint = dwc2_readl(hsotg->regs + GOTGINT);
gotgctl = dwc2_readl(hsotg->regs + GOTGCTL);
dev_dbg(hsotg->dev, "++OTG Interrupt gotgint=%0x [%s]\n", gotgint,
dwc2_op_state_str(hsotg));
if (gotgint & GOTGINT_SES_END_DET) {
dev_dbg(hsotg->dev,
" ++OTG Interrupt: Session End Detected++ (%s)\n",
dwc2_op_state_str(hsotg));
gotgctl = dwc2_readl(hsotg->regs + GOTGCTL);
if (dwc2_is_device_mode(hsotg))
dwc2_hsotg_disconnect(hsotg);
if (hsotg->op_state == OTG_STATE_B_HOST) {
hsotg->op_state = OTG_STATE_B_PERIPHERAL;
} else {
/*
* If not B_HOST and Device HNP still set, HNP did
* not succeed!
*/
if (gotgctl & GOTGCTL_DEVHNPEN) {
dev_dbg(hsotg->dev, "Session End Detected\n");
dev_err(hsotg->dev,
"Device Not Connected/Responding!\n");
}
/*
* If Session End Detected the B-Cable has been
* disconnected
*/
/* Reset to a clean state */
hsotg->lx_state = DWC2_L0;
}
gotgctl = dwc2_readl(hsotg->regs + GOTGCTL);
gotgctl &= ~GOTGCTL_DEVHNPEN;
dwc2_writel(gotgctl, hsotg->regs + GOTGCTL);
}
if (gotgint & GOTGINT_SES_REQ_SUC_STS_CHNG) {
dev_dbg(hsotg->dev,
" ++OTG Interrupt: Session Request Success Status Change++\n");
gotgctl = dwc2_readl(hsotg->regs + GOTGCTL);
if (gotgctl & GOTGCTL_SESREQSCS) {
if (hsotg->core_params->phy_type ==
DWC2_PHY_TYPE_PARAM_FS
&& hsotg->core_params->i2c_enable > 0) {
hsotg->srp_success = 1;
} else {
/* Clear Session Request */
gotgctl = dwc2_readl(hsotg->regs + GOTGCTL);
gotgctl &= ~GOTGCTL_SESREQ;
dwc2_writel(gotgctl, hsotg->regs + GOTGCTL);
}
}
}
if (gotgint & GOTGINT_HST_NEG_SUC_STS_CHNG) {
/*
* Print statements during the HNP interrupt handling
* can cause it to fail
*/
gotgctl = dwc2_readl(hsotg->regs + GOTGCTL);
/*
* WA for 3.00a- HW is not setting cur_mode, even sometimes
* this does not help
*/
if (hsotg->hw_params.snpsid >= DWC2_CORE_REV_3_00a)
udelay(100);
if (gotgctl & GOTGCTL_HSTNEGSCS) {
if (dwc2_is_host_mode(hsotg)) {
hsotg->op_state = OTG_STATE_B_HOST;
/*
* Need to disable SOF interrupt immediately.
* When switching from device to host, the PCD
* interrupt handler won't handle the interrupt
* if host mode is already set. The HCD
* interrupt handler won't get called if the
* HCD state is HALT. This means that the
* interrupt does not get handled and Linux
* complains loudly.
*/
gintmsk = dwc2_readl(hsotg->regs + GINTMSK);
gintmsk &= ~GINTSTS_SOF;
dwc2_writel(gintmsk, hsotg->regs + GINTMSK);
/*
* Call callback function with spin lock
* released
*/
spin_unlock(&hsotg->lock);
/* Initialize the Core for Host mode */
dwc2_hcd_start(hsotg);
spin_lock(&hsotg->lock);
hsotg->op_state = OTG_STATE_B_HOST;
}
} else {
gotgctl = dwc2_readl(hsotg->regs + GOTGCTL);
gotgctl &= ~(GOTGCTL_HNPREQ | GOTGCTL_DEVHNPEN);
dwc2_writel(gotgctl, hsotg->regs + GOTGCTL);
dev_dbg(hsotg->dev, "HNP Failed\n");
dev_err(hsotg->dev,
"Device Not Connected/Responding\n");
}
}
if (gotgint & GOTGINT_HST_NEG_DET) {
/*
* The disconnect interrupt is set at the same time as
* Host Negotiation Detected. During the mode switch all
* interrupts are cleared so the disconnect interrupt
* handler will not get executed.
*/
dev_dbg(hsotg->dev,
" ++OTG Interrupt: Host Negotiation Detected++ (%s)\n",
(dwc2_is_host_mode(hsotg) ? "Host" : "Device"));
if (dwc2_is_device_mode(hsotg)) {
dev_dbg(hsotg->dev, "a_suspend->a_peripheral (%d)\n",
hsotg->op_state);
spin_unlock(&hsotg->lock);
dwc2_hcd_disconnect(hsotg, false);
spin_lock(&hsotg->lock);
hsotg->op_state = OTG_STATE_A_PERIPHERAL;
} else {
/* Need to disable SOF interrupt immediately */
gintmsk = dwc2_readl(hsotg->regs + GINTMSK);
gintmsk &= ~GINTSTS_SOF;
dwc2_writel(gintmsk, hsotg->regs + GINTMSK);
spin_unlock(&hsotg->lock);
dwc2_hcd_start(hsotg);
spin_lock(&hsotg->lock);
hsotg->op_state = OTG_STATE_A_HOST;
}
}
if (gotgint & GOTGINT_A_DEV_TOUT_CHG)
dev_dbg(hsotg->dev,
" ++OTG Interrupt: A-Device Timeout Change++\n");
if (gotgint & GOTGINT_DBNCE_DONE)
dev_dbg(hsotg->dev, " ++OTG Interrupt: Debounce Done++\n");
/* Clear GOTGINT */
dwc2_writel(gotgint, hsotg->regs + GOTGINT);
}
/**
* dwc2_handle_conn_id_status_change_intr() - Handles the Connector ID Status
* Change Interrupt
*
* @hsotg: Programming view of DWC_otg controller
*
* Reads the OTG Interrupt Register (GOTCTL) to determine whether this is a
* Device to Host Mode transition or a Host to Device Mode transition. This only
* occurs when the cable is connected/removed from the PHY connector.
*/
static void dwc2_handle_conn_id_status_change_intr(struct dwc2_hsotg *hsotg)
{
u32 gintmsk;
/* Clear interrupt */
dwc2_writel(GINTSTS_CONIDSTSCHNG, hsotg->regs + GINTSTS);
/* Need to disable SOF interrupt immediately */
gintmsk = dwc2_readl(hsotg->regs + GINTMSK);
gintmsk &= ~GINTSTS_SOF;
dwc2_writel(gintmsk, hsotg->regs + GINTMSK);
dev_dbg(hsotg->dev, " ++Connector ID Status Change Interrupt++ (%s)\n",
dwc2_is_host_mode(hsotg) ? "Host" : "Device");
/*
* Need to schedule a work, as there are possible DELAY function calls.
* Release lock before scheduling workq as it holds spinlock during
* scheduling.
*/
if (hsotg->wq_otg) {
spin_unlock(&hsotg->lock);
queue_work(hsotg->wq_otg, &hsotg->wf_otg);
spin_lock(&hsotg->lock);
}
}
/**
* dwc2_handle_session_req_intr() - This interrupt indicates that a device is
* initiating the Session Request Protocol to request the host to turn on bus
* power so a new session can begin
*
* @hsotg: Programming view of DWC_otg controller
*
* This handler responds by turning on bus power. If the DWC_otg controller is
* in low power mode, this handler brings the controller out of low power mode
* before turning on bus power.
*/
static void dwc2_handle_session_req_intr(struct dwc2_hsotg *hsotg)
{
int ret;
/* Clear interrupt */
dwc2_writel(GINTSTS_SESSREQINT, hsotg->regs + GINTSTS);
dev_dbg(hsotg->dev, "Session request interrupt - lx_state=%d\n",
hsotg->lx_state);
if (dwc2_is_device_mode(hsotg)) {
if (hsotg->lx_state == DWC2_L2) {
ret = dwc2_exit_hibernation(hsotg, true);
if (ret && (ret != -ENOTSUPP))
dev_err(hsotg->dev,
"exit hibernation failed\n");
}
/*
* Report disconnect if there is any previous session
* established
*/
dwc2_hsotg_disconnect(hsotg);
}
}
/*
* This interrupt indicates that the DWC_otg controller has detected a
* resume or remote wakeup sequence. If the DWC_otg controller is in
* low power mode, the handler must brings the controller out of low
* power mode. The controller automatically begins resume signaling.
* The handler schedules a time to stop resume signaling.
*/
static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
{
int ret;
/* Clear interrupt */
dwc2_writel(GINTSTS_WKUPINT, hsotg->regs + GINTSTS);
dev_dbg(hsotg->dev, "++Resume or Remote Wakeup Detected Interrupt++\n");
dev_dbg(hsotg->dev, "%s lxstate = %d\n", __func__, hsotg->lx_state);
if (dwc2_is_device_mode(hsotg)) {
dev_dbg(hsotg->dev, "DSTS=0x%0x\n",
dwc2_readl(hsotg->regs + DSTS));
if (hsotg->lx_state == DWC2_L2) {
u32 dctl = dwc2_readl(hsotg->regs + DCTL);
/* Clear Remote Wakeup Signaling */
dctl &= ~DCTL_RMTWKUPSIG;
dwc2_writel(dctl, hsotg->regs + DCTL);
ret = dwc2_exit_hibernation(hsotg, true);
if (ret && (ret != -ENOTSUPP))
dev_err(hsotg->dev, "exit hibernation failed\n");
call_gadget(hsotg, resume);
}
/* Change to L0 state */
hsotg->lx_state = DWC2_L0;
} else {
if (hsotg->core_params->hibernation)
return;
if (hsotg->lx_state != DWC2_L1) {
u32 pcgcctl = dwc2_readl(hsotg->regs + PCGCTL);
/* Restart the Phy Clock */
pcgcctl &= ~PCGCTL_STOPPCLK;
dwc2_writel(pcgcctl, hsotg->regs + PCGCTL);
mod_timer(&hsotg->wkp_timer,
jiffies + msecs_to_jiffies(71));
} else {
/* Change to L0 state */
hsotg->lx_state = DWC2_L0;
}
}
}
/*
* This interrupt indicates that a device has been disconnected from the
* root port
*/
static void dwc2_handle_disconnect_intr(struct dwc2_hsotg *hsotg)
{
dwc2_writel(GINTSTS_DISCONNINT, hsotg->regs + GINTSTS);
dev_dbg(hsotg->dev, "++Disconnect Detected Interrupt++ (%s) %s\n",
dwc2_is_host_mode(hsotg) ? "Host" : "Device",
dwc2_op_state_str(hsotg));
if (hsotg->op_state == OTG_STATE_A_HOST)
dwc2_hcd_disconnect(hsotg, false);
}
/*
* This interrupt indicates that SUSPEND state has been detected on the USB.
*
* For HNP the USB Suspend interrupt signals the change from "a_peripheral"
* to "a_host".
*
* When power management is enabled the core will be put in low power mode.
*/
static void dwc2_handle_usb_suspend_intr(struct dwc2_hsotg *hsotg)
{
u32 dsts;
int ret;
/* Clear interrupt */
dwc2_writel(GINTSTS_USBSUSP, hsotg->regs + GINTSTS);
dev_dbg(hsotg->dev, "USB SUSPEND\n");
if (dwc2_is_device_mode(hsotg)) {
/*
* Check the Device status register to determine if the Suspend
* state is active
*/
dsts = dwc2_readl(hsotg->regs + DSTS);
dev_dbg(hsotg->dev, "DSTS=0x%0x\n", dsts);
dev_dbg(hsotg->dev,
"DSTS.Suspend Status=%d HWCFG4.Power Optimize=%d\n",
!!(dsts & DSTS_SUSPSTS),
hsotg->hw_params.power_optimized);
if ((dsts & DSTS_SUSPSTS) && hsotg->hw_params.power_optimized) {
/* Ignore suspend request before enumeration */
if (!dwc2_is_device_connected(hsotg)) {
dev_dbg(hsotg->dev,
"ignore suspend request before enumeration\n");
return;
}
ret = dwc2_enter_hibernation(hsotg);
if (ret) {
if (ret != -ENOTSUPP)
dev_err(hsotg->dev,
"enter hibernation failed\n");
goto skip_power_saving;
}
udelay(100);
/* Ask phy to be suspended */
if (!IS_ERR_OR_NULL(hsotg->uphy))
usb_phy_set_suspend(hsotg->uphy, true);
skip_power_saving:
/*
* Change to L2 (suspend) state before releasing
* spinlock
*/
hsotg->lx_state = DWC2_L2;
/* Call gadget suspend callback */
call_gadget(hsotg, suspend);
}
} else {
if (hsotg->op_state == OTG_STATE_A_PERIPHERAL) {
dev_dbg(hsotg->dev, "a_peripheral->a_host\n");
/* Change to L2 (suspend) state */
hsotg->lx_state = DWC2_L2;
/* Clear the a_peripheral flag, back to a_host */
spin_unlock(&hsotg->lock);
dwc2_hcd_start(hsotg);
spin_lock(&hsotg->lock);
hsotg->op_state = OTG_STATE_A_HOST;
}
}
}
#define GINTMSK_COMMON (GINTSTS_WKUPINT | GINTSTS_SESSREQINT | \
GINTSTS_CONIDSTSCHNG | GINTSTS_OTGINT | \
GINTSTS_MODEMIS | GINTSTS_DISCONNINT | \
GINTSTS_USBSUSP | GINTSTS_PRTINT)
/*
* This function returns the Core Interrupt register
*/
static u32 dwc2_read_common_intr(struct dwc2_hsotg *hsotg)
{
u32 gintsts;
u32 gintmsk;
u32 gahbcfg;
u32 gintmsk_common = GINTMSK_COMMON;
gintsts = dwc2_readl(hsotg->regs + GINTSTS);
gintmsk = dwc2_readl(hsotg->regs + GINTMSK);
gahbcfg = dwc2_readl(hsotg->regs + GAHBCFG);
/* If any common interrupts set */
if (gintsts & gintmsk_common)
dev_dbg(hsotg->dev, "gintsts=%08x gintmsk=%08x\n",
gintsts, gintmsk);
if (gahbcfg & GAHBCFG_GLBL_INTR_EN)
return gintsts & gintmsk & gintmsk_common;
else
return 0;
}
/*
* Common interrupt handler
*
* The common interrupts are those that occur in both Host and Device mode.
* This handler handles the following interrupts:
* - Mode Mismatch Interrupt
* - OTG Interrupt
* - Connector ID Status Change Interrupt
* - Disconnect Interrupt
* - Session Request Interrupt
* - Resume / Remote Wakeup Detected Interrupt
* - Suspend Interrupt
*/
irqreturn_t dwc2_handle_common_intr(int irq, void *dev)
{
struct dwc2_hsotg *hsotg = dev;
u32 gintsts;
irqreturn_t retval = IRQ_NONE;
spin_lock(&hsotg->lock);
if (!dwc2_is_controller_alive(hsotg)) {
dev_warn(hsotg->dev, "Controller is dead\n");
goto out;
}
gintsts = dwc2_read_common_intr(hsotg);
if (gintsts & ~GINTSTS_PRTINT)
retval = IRQ_HANDLED;
if (gintsts & GINTSTS_MODEMIS)
dwc2_handle_mode_mismatch_intr(hsotg);
if (gintsts & GINTSTS_OTGINT)
dwc2_handle_otg_intr(hsotg);
if (gintsts & GINTSTS_CONIDSTSCHNG)
dwc2_handle_conn_id_status_change_intr(hsotg);
if (gintsts & GINTSTS_DISCONNINT)
dwc2_handle_disconnect_intr(hsotg);
if (gintsts & GINTSTS_SESSREQINT)
dwc2_handle_session_req_intr(hsotg);
if (gintsts & GINTSTS_WKUPINT)
dwc2_handle_wakeup_detected_intr(hsotg);
if (gintsts & GINTSTS_USBSUSP)
dwc2_handle_usb_suspend_intr(hsotg);
if (gintsts & GINTSTS_PRTINT) {
/*
* The port interrupt occurs while in device mode with HPRT0
* Port Enable/Disable
*/
if (dwc2_is_device_mode(hsotg)) {
dev_dbg(hsotg->dev,
" --Port interrupt received in Device mode--\n");
dwc2_handle_usb_port_intr(hsotg);
retval = IRQ_HANDLED;
}
}
out:
spin_unlock(&hsotg->lock);
return retval;
}
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