USB detection changes. c200/e200: Consider USB to be powered when charger is plugged but detect USB connection by bus reset. When received, disconnect and restart the driver fully enabled. imx31: Fix hack used to make initial connect succeeded-- set PHY type before initial reset. General: Move some target code out of usb-drv-arc.c and implement it in respective usb sources and CPU headers so things stay clean.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@19797 a1c6a512-1295-4272-9138-f99709370657

18 files changed, 276 insertions, 144 deletions

diff --git a/bootloader/gigabeat-s.c b/bootloader/gigabeat-s.c
index e860a2e..15cbcbe 100644
--- a/bootloader/gigabeat-s.c
+++ b/bootloader/gigabeat-s.c
@@ -95,7 +95,6 @@ static void handle_usb(void)
     if (!usb_plugged() || !pause_if_button_pressed(true))
     {
         /* Bang on the controller */
-        usb_init_device();
         return;
     }
 
diff --git a/firmware/export/config-c200.h b/firmware/export/config-c200.h
index d68d214..ff260dc 100644
--- a/firmware/export/config-c200.h
+++ b/firmware/export/config-c200.h
@@ -180,6 +180,9 @@
 
 /* enable these for the experimental usb stack */
 #define HAVE_USBSTACK
+#ifndef BOOTLOADER
+#define USB_DETECT_BY_DRV
+#endif
 #define USB_VENDOR_ID 0x0781
 #define USB_PRODUCT_ID 0x7450
 
diff --git a/firmware/export/config-e200.h b/firmware/export/config-e200.h
index 2be64d9..7b27391 100644
--- a/firmware/export/config-e200.h
+++ b/firmware/export/config-e200.h
@@ -177,6 +177,9 @@
 
 /* enable these for the experimental usb stack */
 #define HAVE_USBSTACK
+#ifndef BOOTLOADER
+#define USB_DETECT_BY_DRV
+#endif
 #define USB_VENDOR_ID 0x0781
 #define USB_PRODUCT_ID 0x7421
 
diff --git a/firmware/export/config-gigabeat-s.h b/firmware/export/config-gigabeat-s.h
index 64f351c..9e6029f 100644
--- a/firmware/export/config-gigabeat-s.h
+++ b/firmware/export/config-gigabeat-s.h
@@ -176,10 +176,12 @@
 /* USB On-the-go */
 #define CONFIG_USBOTG USBOTG_ARC
 
-/* enable these for the experimental usb stack */
+/* enable these for the usb stack */
 #define USE_ROCKBOX_USB
 #define HAVE_USBSTACK
 #define USB_STORAGE
+/* usb stack and driver settings */
+#define USB_PORTSCX_PHY_TYPE PORTSCX_PTS_ULPI
 #define USB_VENDOR_ID 0x0930
 #define USB_PRODUCT_ID 0x0010
 
@@ -201,7 +203,7 @@
 /* Offset ( in the firmware file's header ) to the real data */
 #define FIRMWARE_OFFSET_FILE_DATA 8
 
-#define HAVE_SERIAL
+//#define HAVE_SERIAL
 #define HAVE_VOLUME_IN_LIST
 
 /*Remove Comments from UART_INT to enable the UART interrupts,*/
diff --git a/firmware/export/imx31l.h b/firmware/export/imx31l.h
index b572c78..b55a56b 100755
--- a/firmware/export/imx31l.h
+++ b/firmware/export/imx31l.h
@@ -36,7 +36,11 @@
 #define FRAME_SIZE    (240*320*2)
 
 #define DEVBSS_ATTR   __attribute__((section(".devbss"),nocommon))
-#define QHARRAY_ATTR  __attribute__((section(".qharray"),nocommon))
+/* USBOTG */
+#define USB_QHARRAY_ATTR    __attribute__((section(".qharray"),nocommon,aligned(2048)))
+#define USB_NUM_ENDPOINTS   8
+#define USB_DEVBSS_ATTR     DEVBSS_ATTR
+#define USB_BASE            OTG_BASE_ADDR
 
 /*
  * AIPS 1
@@ -1580,6 +1584,4 @@
 #define UART_FIFO_CTRL          0x881
 #define TIMEOUT                 1000
 
-#define USB_BASE                OTG_BASE_ADDR
-
 #endif /* __IMX31L_H__ */
diff --git a/firmware/export/pp5020.h b/firmware/export/pp5020.h
index b4919a2..0f622a9 100644
--- a/firmware/export/pp5020.h
+++ b/firmware/export/pp5020.h
@@ -23,7 +23,12 @@
 
 /* All info gleaned and/or copied from the iPodLinux project. */
 
-#define QHARRAY_ATTR   __attribute__((section(".qharray"),nocommon))
+/* USBOTG */
+#define USB_NUM_ENDPOINTS  3
+/* This needs to be 2048 byte aligned, but USB_QHARRAY_ATTR should take care
+ * of that */
+#define USB_QHARRAY_ATTR   __attribute__((section(".qharray"),nocommon,aligned(4)))
+#define USB_DEVBSS_ATTR    IBSS_ATTR
 
 /* DRAM starts at 0x10000000, but in Rockbox we remap it to 0x00000000 */
 #define DRAM_START       0x10000000
diff --git a/firmware/export/usb.h b/firmware/export/usb.h
index a6cfad5..0a0539a 100644
--- a/firmware/export/usb.h
+++ b/firmware/export/usb.h
@@ -33,8 +33,11 @@
 enum {
     USB_INSERTED,            /* Event+State */
     USB_EXTRACTED,           /* Event+State */
-#ifdef HAVE_USB_POWER
-    USB_POWERED,             /* State */
+#if defined(HAVE_USB_POWER) || defined(USB_DETECT_BY_DRV)
+    USB_POWERED,             /* Event+State */
+#endif
+#ifdef USB_DETECT_BY_DRV
+    USB_UNPOWERED,           /* Event */
 #endif
 #ifdef HAVE_LCD_BITMAP
     USB_SCREENDUMP,          /* State */
@@ -107,6 +110,7 @@ struct usb_transfer_completion_event_data
 
 void usb_init(void);
 void usb_enable(bool on);
+void usb_attach(void);
 void usb_start_monitoring(void);
 void usb_close(void);
 void usb_acknowledge(long id);
diff --git a/firmware/export/usb_core.h b/firmware/export/usb_core.h
index 7af8e43..d0c8270 100644
--- a/firmware/export/usb_core.h
+++ b/firmware/export/usb_core.h
@@ -7,7 +7,7 @@
  *                     \/            \/     \/    \/            \/
  * $Id$
  *
- * Copyright (C) 2007 by Björn Stenberg
+ * Copyright (C) 2007 by Björn Stenberg
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -35,14 +35,6 @@
 
 /* endpoints */
 #define EP_CONTROL 0
-#if CONFIG_CPU == IMX31L
-#define NUM_ENDPOINTS 8
-#define USBDEVBSS_ATTR  DEVBSS_ATTR
-#else
-#define USBDEVBSS_ATTR  IBSS_ATTR
-#define NUM_ENDPOINTS 3
-#endif
-
 extern int usb_max_pkt_size;
 
 struct usb_class_driver;
diff --git a/firmware/export/usb_drv.h b/firmware/export/usb_drv.h
index 3d2e689..23f6f4c 100644
--- a/firmware/export/usb_drv.h
+++ b/firmware/export/usb_drv.h
@@ -24,9 +24,13 @@
 #include "kernel.h"
 
 void usb_drv_startup(void);
+void usb_drv_usb_detect_event(void); /* Target implemented */
+void usb_drv_int_enable(bool enable); /* Target implemented */
+void usb_drv_reset(void);
 void usb_drv_init(void);
 void usb_drv_exit(void);
-void usb_drv_int(void);
+void usb_drv_attach(void);
+void usb_drv_int(void); /* Call from target INT handler */
 void usb_drv_stall(int endpoint, bool stall,bool in);
 bool usb_drv_stalled(int endpoint,bool in);
 int usb_drv_send(int endpoint, void* ptr, int length);
diff --git a/firmware/target/arm/imx31/gigabeat-s/system-target.h b/firmware/target/arm/imx31/gigabeat-s/system-target.h
index 847e6cf..b99b31d 100644
--- a/firmware/target/arm/imx31/gigabeat-s/system-target.h
+++ b/firmware/target/arm/imx31/gigabeat-s/system-target.h
@@ -31,6 +31,14 @@
 #define CPUFREQ_MAX CPU_FREQ
 #endif
 
+/* For USB driver - no accuracy assurance */
+static inline void udelay(unsigned int usecs)
+{
+    unsigned int x;
+    for (x = 0; x < 300*usecs; x++)
+        asm volatile ("");
+}
+
 #if 0
 static inline void udelay(unsigned int usecs)
 {
diff --git a/firmware/target/arm/imx31/gigabeat-s/usb-imx31.c b/firmware/target/arm/imx31/gigabeat-s/usb-imx31.c
index cd8b513..c0d7cb8 100644
--- a/firmware/target/arm/imx31/gigabeat-s/usb-imx31.c
+++ b/firmware/target/arm/imx31/gigabeat-s/usb-imx31.c
@@ -29,6 +29,7 @@
 #include "usb-target.h"
 #include "clkctl-imx31.h"
 #include "power-imx31.h"
+#include "avic-imx31.h"
 #include "mc13783.h"
 
 static int usb_status = USB_EXTRACTED;
@@ -75,11 +76,7 @@ bool usb_plugged(void)
 
 void usb_init_device(void)
 {
-    imx31_clkctl_module_clock_gating(CG_USBOTG, CGM_ON_ALL);
-
-    enable_transceiver(true);
-
-    /* Module will be turned off later after firmware init */
+    /* Do one-time inits */
     usb_drv_startup();
 
     /* Initially poll */
@@ -91,19 +88,37 @@ void usb_init_device(void)
 
 void usb_enable(bool on)
 {
+    /* Module clock should be on since since this could be called with
+     * OFF initially and writing module registers would hardlock otherwise. */
+    imx31_clkctl_module_clock_gating(CG_USBOTG, CGM_ON_ALL);
+    enable_transceiver(true);
+
     if (on)
     {
-        imx31_clkctl_module_clock_gating(CG_USBOTG, CGM_ON_ALL);
-        enable_transceiver(true);
         usb_core_init();
     }
     else
     {
-        /* Module clock should be on since this could be called first */
-        imx31_clkctl_module_clock_gating(CG_USBOTG, CGM_ON_ALL);
-        enable_transceiver(true);
         usb_core_exit();
         enable_transceiver(false);
         imx31_clkctl_module_clock_gating(CG_USBOTG, CGM_OFF);
     }
 }
+
+void usb_attach(void)
+{
+    usb_enable(true);
+}
+
+static void __attribute__((interrupt("IRQ"))) USB_OTG_HANDLER(void)
+{
+    usb_drv_int(); /* Call driver handler */
+}
+
+void usb_drv_int_enable(bool enable)
+{
+    if (enable)
+        avic_enable_int(USB_OTG, IRQ, 7, USB_OTG_HANDLER);
+    else    
+        avic_disable_int(USB_OTG);
+}
diff --git a/firmware/target/arm/powermgmt-ascodec.c b/firmware/target/arm/powermgmt-ascodec.c
index ab9fd7b..6ee6209 100644
--- a/firmware/target/arm/powermgmt-ascodec.c
+++ b/firmware/target/arm/powermgmt-ascodec.c
@@ -27,6 +27,8 @@
 #include "adc.h"
 #include "powermgmt.h"
 #include "power.h"
+#include "usb-target.h"
+#include "usb.h"
 
 /*===========================================================================
  * These parameters may be defined per target:
@@ -132,6 +134,10 @@ static inline void charger_plugged(void)
 {
     batt_threshold = BATT_FULL_VOLTAGE; /* Start with topped value. */
     battery_voltage_sync();
+#if defined(USB_STATUS_BY_EVENT) && defined(USB_DETECT_BY_DRV)
+    /* Charger pin detect is USB pin detect */
+    usb_connect_event(true);
+#endif
 }
 
 static inline void charger_control(void)
@@ -186,6 +192,10 @@ static inline void charger_unplugged(void)
     disable_charger();
     if (charge_state >= CHARGE_STATE_ERROR)
         charge_state = DISCHARGING; /* Reset error */
+#if defined(USB_STATUS_BY_EVENT) && defined(USB_DETECT_BY_DRV)
+    /* Charger pin detect is USB pin detect */
+    usb_connect_event(false);
+#endif
 }
 
 /* Main charging algorithm - called from powermgmt.c */
diff --git a/firmware/target/arm/usb-drv-arc.c b/firmware/target/arm/usb-drv-arc.c
index 1cdc0f9..99845c2 100644
--- a/firmware/target/arm/usb-drv-arc.c
+++ b/firmware/target/arm/usb-drv-arc.c
@@ -9,7 +9,7 @@
  *
  * Driver for ARC USBOTG Device Controller
  *
- * Copyright (C) 2007 by Björn Stenberg
+ * Copyright (C) 2007 by Björn Stenberg
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -33,11 +33,6 @@
 //#define LOGF_ENABLE
 #include "logf.h"
 
-#if CONFIG_CPU == IMX31L
-#include "avic-imx31.h"
-static void __attribute__((interrupt("IRQ"))) USB_OTG_HANDLER(void);
-#endif
-
 /* USB device mode registers (Little Endian) */
 
 #define REG_ID               (*(volatile unsigned int *)(USB_BASE+0x000))
@@ -326,8 +321,8 @@ struct transfer_descriptor {
     unsigned int reserved;
 } __attribute__ ((packed));
 
-static struct transfer_descriptor td_array[NUM_ENDPOINTS*2]
-    USBDEVBSS_ATTR __attribute__((aligned(32)));
+static struct transfer_descriptor td_array[USB_NUM_ENDPOINTS*2]
+    USB_DEVBSS_ATTR __attribute__((aligned(32)));
 
 /* manual: 32.13.1 Endpoint Queue Head (dQH) */
 struct queue_head {
@@ -342,17 +337,10 @@ struct queue_head {
     unsigned int wait;              /* for softwate use, indicates if the transfer is blocking */
 } __attribute__((packed));
 
-#if CONFIG_CPU == IMX31L
-static struct queue_head qh_array[NUM_ENDPOINTS*2]
-    QHARRAY_ATTR __attribute__((aligned (2048)));
-#else
-/* This still needs to be 2048 byte aligned, but QHARRAY_ATTR should take
-   care of that */
-static struct queue_head qh_array[NUM_ENDPOINTS*2]
-    QHARRAY_ATTR __attribute__((aligned (4)));
-#endif
+static struct queue_head qh_array[USB_NUM_ENDPOINTS*2]
+    USB_QHARRAY_ATTR;
 
-static struct wakeup transfer_completion_signal[NUM_ENDPOINTS*2]
+static struct wakeup transfer_completion_signal[USB_NUM_ENDPOINTS*2]
     SHAREDBSS_ATTR;
 
 static const unsigned int pipe2mask[] = {
@@ -363,7 +351,7 @@ static const unsigned int pipe2mask[] = {
     0x10, 0x100000,
 };
 
-static char ep_allocation[NUM_ENDPOINTS];
+static char ep_allocation[USB_NUM_ENDPOINTS];
 
 /*-------------------------------------------------------------------------*/
 static void transfer_completed(void);
@@ -378,52 +366,46 @@ static void init_control_queue_heads(void);
 static void init_bulk_queue_heads(void);
 static void init_endpoints(void);
 /*-------------------------------------------------------------------------*/
-
-bool usb_drv_powered(void)
+static void usb_drv_stop(void)
 {
-    return (REG_OTGSC & OTGSC_B_SESSION_VALID) ? true : false;
+    /* disable interrupts */
+    REG_USBINTR = 0;
+    /* stop usb controller (disconnect) */
+    REG_USBCMD &= ~USBCMD_RUN;
 }
 
-/* One-time driver startup init */
-void usb_drv_startup(void)
+void usb_drv_reset(void)
 {
-#if CONFIG_CPU == IMX31L && defined(BOOTLOADER)
-    /* This is the bootloader - activate the OTG controller or cold
-     * connect later could/will fail */
+    int oldlevel = disable_irq_save();
     REG_USBCMD &= ~USBCMD_RUN;
+    restore_irq(oldlevel);
 
+#ifdef USB_PORTSCX_PHY_TYPE
+    /* If a PHY type is specified, set it now */
+    REG_PORTSC1 = (REG_PORTSC1 & ~PORTSCX_PHY_TYPE_SEL) | USB_PORTSCX_PHY_TYPE;
+#endif
     sleep(HZ/20);
     REG_USBCMD |= USBCMD_CTRL_RESET;
     while (REG_USBCMD & USBCMD_CTRL_RESET);
+}
 
-    /* Set to ULPI */
-    REG_PORTSC1 = (REG_PORTSC1 & ~PORTSCX_PHY_TYPE_SEL) | PORTSCX_PTS_ULPI;
-    sleep(HZ/10);
-#endif
-
+/* One-time driver startup init */
+void usb_drv_startup(void)
+{
     /* Initialize all the signal objects once */
     int i;
-    for(i=0;i<NUM_ENDPOINTS*2;i++) {
+    for(i=0;i<USB_NUM_ENDPOINTS*2;i++) {
         wakeup_init(&transfer_completion_signal[i]);
     }
 }
 
 /* manual: 32.14.1 Device Controller Initialization */
-void usb_drv_init(void)
+static void _usb_drv_init(bool attach)
 {
-    REG_USBCMD &= ~USBCMD_RUN;
-    sleep(HZ/20);
-    REG_USBCMD |= USBCMD_CTRL_RESET;
-    while (REG_USBCMD & USBCMD_CTRL_RESET);
-
+    usb_drv_reset();
 
     REG_USBMODE = USBMODE_CTRL_MODE_DEVICE;
 
-#if CONFIG_CPU == IMX31L
-    /* Set to ULPI */
-    REG_PORTSC1 = (REG_PORTSC1 & ~PORTSCX_PHY_TYPE_SEL) | PORTSCX_PTS_ULPI;
-#endif
-
 #ifdef USB_NO_HIGH_SPEED
     /* Force device to full speed */
     /* See 32.9.5.9.2 */
@@ -436,69 +418,76 @@ void usb_drv_init(void)
     REG_ENDPOINTLISTADDR = (unsigned int)qh_array;
     REG_DEVICEADDR = 0;
 
-    /* enable USB interrupts */
-    REG_USBINTR =
-        USBINTR_INT_EN |
-        USBINTR_ERR_INT_EN |
-        USBINTR_PTC_DETECT_EN |
-        USBINTR_RESET_EN |
-        USBINTR_SYS_ERR_EN;
-
-#if CONFIG_CPU == IMX31L
-    avic_enable_int(USB_OTG, IRQ, 7, USB_OTG_HANDLER);
-#else
-    /* enable USB IRQ in CPU */
-    CPU_INT_EN = USB_MASK;
+#ifdef USB_DETECT_BY_DRV
+    if (!attach) {
+        /* enable RESET interrupt */
+        REG_USBINTR = USBINTR_RESET_EN;
+    }
+    else
 #endif
+    {
+        /* enable USB interrupts */
+        REG_USBINTR =
+            USBINTR_INT_EN |
+            USBINTR_ERR_INT_EN |
+            USBINTR_PTC_DETECT_EN |
+            USBINTR_RESET_EN;
+    }
+
+    usb_drv_int_enable(true);
 
     /* go go go */
     REG_USBCMD |= USBCMD_RUN;
 
-
     logf("usb_drv_init() finished");
     logf("usb id %x", REG_ID);
     logf("usb dciversion %x", REG_DCIVERSION);
     logf("usb dccparams %x", REG_DCCPARAMS);
 
     /* now a bus reset will occur. see bus_reset() */
+    (void)attach;
 }
 
-void usb_drv_exit(void)
+/** With USB_DETECT_BY_DRV, attach is distinct from init, otherwise eqivalent. **/
+
+/* USB_DETECT_BY_DRV - enable bus reset detection only
+ * else fully enable driver */
+void usb_drv_init(void)
 {
-    /* disable interrupts */
-    REG_USBINTR = 0;
+    _usb_drv_init(false);
+}
 
-    /* stop usb controller */
-    REG_USBCMD &= ~USBCMD_RUN;
+#ifdef USB_DETECT_BY_DRV
+/* fully enable driver */
+void usb_drv_attach(void)
+{
+    sleep(HZ/10);
+    _usb_drv_init(true);
+}
+#endif /* USB_DETECT_BY_DRV */
+
+void usb_drv_exit(void)
+{
+    usb_drv_stop();
 
     /* TODO : is one of these needed to save power ?
     REG_PORTSC1 |= PORTSCX_PHY_LOW_POWER_SPD;
     REG_USBCMD |= USBCMD_CTRL_RESET;
     */
 
-#if CONFIG_CPU == IMX31L
-    avic_disable_int(USB_OTG);
-#else
-    CPU_INT_DIS = USB_MASK;
-#endif
-
-    cancel_cpu_boost();
+    usb_drv_int_enable(false);
 }
 
-#if CONFIG_CPU == IMX31L
-static void __attribute__((interrupt("IRQ"))) USB_OTG_HANDLER(void)
-#else
 void usb_drv_int(void)
-#endif
 {
-    unsigned int status = REG_USBSTS;
+    unsigned int usbintr = REG_USBINTR; /* Only watch enabled ints */
+    unsigned int status = REG_USBSTS & usbintr;
 
 #if 0
     if (status & USBSTS_INT) logf("int: usb ioc");
     if (status & USBSTS_ERR) logf("int: usb err");
     if (status & USBSTS_PORT_CHANGE) logf("int: portchange");
     if (status & USBSTS_RESET) logf("int: reset");
-    if (status & USBSTS_SYS_ERR) logf("int: syserr");
 #endif
 
     /* usb transaction interrupt */
@@ -523,8 +512,18 @@ void usb_drv_int(void)
     /* reset interrupt */
     if (status & USBSTS_RESET) {
         REG_USBSTS = USBSTS_RESET;
-        bus_reset();
-        usb_core_bus_reset(); /* tell mom */
+#ifdef USB_DETECT_BY_DRV
+        if (UNLIKELY(usbintr == USBINTR_RESET_EN)) {
+            /* USB detected - detach and inform */
+            usb_drv_stop();
+            usb_drv_usb_detect_event();
+        }
+        else
+#endif
+        {
+            bus_reset();
+            usb_core_bus_reset(); /* tell mom */
+        }
     }
 
     /* port change */
@@ -588,7 +587,14 @@ int usb_drv_port_speed(void)
 
 bool usb_drv_connected(void)
 {
-    return ((REG_PORTSC1 & PORTSCX_CURRENT_CONNECT_STATUS) !=0);
+    return (REG_PORTSC1 &
+        (PORTSCX_PORT_SUSPEND | PORTSCX_CURRENT_CONNECT_STATUS))
+            == PORTSCX_CURRENT_CONNECT_STATUS;
+}
+
+bool usb_drv_powered(void)
+{
+    return (REG_OTGSC & OTGSC_B_SESSION_VALID) ? true : false;
 }
 
 void usb_drv_set_address(int address)
@@ -628,10 +634,7 @@ void usb_drv_set_test_mode(int mode)
             REG_PORTSC1 |= PORTSCX_PTC_FORCE_EN;
             break;
     }
-    REG_USBCMD &= ~USBCMD_RUN;
-    sleep(HZ/20);
-    REG_USBCMD |= USBCMD_CTRL_RESET;
-    while (REG_USBCMD & USBCMD_CTRL_RESET);
+    usb_drv_reset();
     REG_USBCMD |= USBCMD_RUN;
 }
 
@@ -735,7 +738,7 @@ void usb_drv_cancel_all_transfers(void)
     while (REG_ENDPTFLUSH);
 
     memset(td_array, 0, sizeof td_array);
-    for(i=0;i<NUM_ENDPOINTS*2;i++) {
+    for(i=0;i<USB_NUM_ENDPOINTS*2;i++) {
         if(qh_array[i].wait) {
             qh_array[i].wait=0;
             qh_array[i].status=DTD_STATUS_HALTED;
@@ -750,7 +753,7 @@ int usb_drv_request_endpoint(int dir)
 
     bit=(dir & USB_DIR_IN)? 2:1;
 
-    for (i=1; i < NUM_ENDPOINTS; i++) {
+    for (i=1; i < USB_NUM_ENDPOINTS; i++) {
         if((ep_allocation[i] & bit)!=0)
             continue;
         ep_allocation[i] |= bit;
@@ -819,7 +822,7 @@ static void transfer_completed(void)
     unsigned int mask = REG_ENDPTCOMPLETE;
     REG_ENDPTCOMPLETE = mask;
 
-    for (ep=0; ep<NUM_ENDPOINTS; ep++) {
+    for (ep=0; ep<USB_NUM_ENDPOINTS; ep++) {
         int dir;
         for (dir=0; dir<2; dir++) {
             int pipe = ep * 2 + dir;
@@ -869,13 +872,8 @@ static void bus_reset(void)
             logf("usb: double reset");
             return;
         }
-#if CONFIG_CPU == IMX31L
-        int x;
-        for (x = 0; x < 30000; x++)
-            asm volatile ("");
-#else
+
         udelay(100);
-#endif
     }
     if (REG_ENDPTPRIME) {
         logf("usb: short reset timeout");
@@ -917,7 +915,7 @@ static void init_bulk_queue_heads(void)
     /* TODO: this should take ep_allocation into account */
 
     /*** bulk ***/
-    for(i=1;i<NUM_ENDPOINTS;i++) {
+    for(i=1;i<USB_NUM_ENDPOINTS;i++) {
         qh_array[i*2].max_pkt_length = rx_packetsize << QH_MAX_PKT_LEN_POS | QH_ZLT_SEL;
         qh_array[i*2].dtd.next_td_ptr = QH_NEXT_TERMINATE;
         qh_array[i*2+1].max_pkt_length = tx_packetsize << QH_MAX_PKT_LEN_POS | QH_ZLT_SEL;
@@ -930,7 +928,7 @@ static void init_endpoints(void)
     int i;
     /* TODO: this should take ep_allocation into account */
     /* bulk */
-    for(i=1;i<NUM_ENDPOINTS;i++) {
+    for(i=1;i<USB_NUM_ENDPOINTS;i++) {
         REG_ENDPTCTRL(i) =
             EPCTRL_RX_DATA_TOGGLE_RST | EPCTRL_RX_ENABLE |
             EPCTRL_TX_DATA_TOGGLE_RST | EPCTRL_TX_ENABLE |
diff --git a/firmware/target/arm/usb-fw-pp502x.c b/firmware/target/arm/usb-fw-pp502x.c
index a41ef9a..8a6d786 100644
--- a/firmware/target/arm/usb-fw-pp502x.c
+++ b/firmware/target/arm/usb-fw-pp502x.c
@@ -25,13 +25,13 @@
  ****************************************************************************/
 #include "config.h"
 #include "system.h"
+#include "usb-target.h"
 #include "usb.h"
 #include "button.h"
 #include "ata.h"
 #include "string.h"
 #include "usb_core.h"
 #include "usb_drv.h"
-#include "usb-target.h"
 
 void usb_init_device(void)
 {
@@ -94,6 +94,31 @@ void usb_enable(bool on)
     }
 }
 
+void usb_attach(void)
+{
+#ifdef USB_DETECT_BY_DRV
+    usb_drv_attach();
+#else
+    usb_enable(true);
+#endif
+}
+
+#ifdef USB_DETECT_BY_DRV
+/* Cannot tell charger pin from USB pin */
+static int usb_status = USB_EXTRACTED;
+
+void usb_connect_event(bool inserted)
+{
+    usb_status = inserted ? USB_INSERTED : USB_EXTRACTED;
+    usb_status_event(inserted ? USB_POWERED : USB_UNPOWERED);
+}
+
+/* Called during the bus reset interrupt when in detect mode */
+void usb_drv_usb_detect_event(void)
+{
+    usb_status_event(USB_INSERTED);
+}
+#else /* !USB_DETECT_BY_DRV */
 static bool usb_pin_detect(void)
 {
     bool retval = false;
@@ -110,12 +135,12 @@ static bool usb_pin_detect(void)
         retval = true;
 
 #elif defined(SANSA_C200)
-    /* GPIO H bit 1 is usb detect */
+    /* GPIO H bit 1 is usb/charger detect */
     if (GPIOH_INPUT_VAL & 0x02)
         retval = true;
 
 #elif defined(SANSA_E200)
-    /* GPIO B bit 4 is usb detect */
+    /* GPIO B bit 4 is usb/charger detect */
     if (GPIOB_INPUT_VAL & 0x10)
         retval = true;
 
@@ -137,16 +162,32 @@ static bool usb_pin_detect(void)
 
     return retval;
 }
+#endif /* USB_DETECT_BY_DRV */
 
-/* detect host or charger (INSERTED or POWERED) */
+void usb_drv_int_enable(bool enable)
+{
+    /* enable/disable USB IRQ in CPU */
+    if(enable) {
+        CPU_INT_EN = USB_MASK;
+    }
+    else {
+        CPU_INT_DIS = USB_MASK;
+    }
+}
+
+/* detect host or charger (INSERTED or EXTRACTED) */
 int usb_detect(void)
 {
+#ifdef USB_DETECT_BY_DRV
+    return usb_status;
+#else
     if(usb_pin_detect()) {
         return USB_INSERTED;
     }
     else {
         return USB_EXTRACTED;
     }
+#endif
 }
 
 #if defined(IPOD_COLOR) || defined(IPOD_4G) \
diff --git a/firmware/target/arm/usb-target.h b/firmware/target/arm/usb-target.h
index cdf6776..913ad80 100644
--- a/firmware/target/arm/usb-target.h
+++ b/firmware/target/arm/usb-target.h
@@ -23,4 +23,11 @@
 
 void usb_init_device(void);
 
+#ifndef BOOTLOADER
+#if defined(SANSA_C200) || defined(SANSA_E200)
+#define USB_STATUS_BY_EVENT /* No USB tick */
+void usb_connect_event(bool inserted);
+#endif
+#endif /* BOOTLOADER */
+
 #endif
diff --git a/firmware/usb.c b/firmware/usb.c
index 918d980..10a7ae1 100644
--- a/firmware/usb.c
+++ b/firmware/usb.c
@@ -34,11 +34,11 @@
 #include "disk.h"
 #include "panic.h"
 #include "lcd.h"
+#include "usb-target.h"
 #include "usb.h"
 #include "button.h"
 #include "sprintf.h"
 #include "string.h"
-#include "usb-target.h"
 #ifdef HAVE_USBSTACK
 #include "usb_core.h"
 #endif
@@ -129,11 +129,13 @@ static inline void usb_slave_mode(bool on)
 #ifdef HAVE_PRIORITY_SCHEDULING
         thread_set_priority(THREAD_ID_CURRENT, PRIORITY_REALTIME);
 #endif
-        usb_enable(true);
+        usb_attach();
     }
     else /* usb_state == USB_INSERTED (only!) */
     {
+#ifndef USB_DETECT_BY_DRV
         usb_enable(false);
+#endif
 #ifdef HAVE_PRIORITY_SCHEDULING
         thread_set_priority(THREAD_ID_CURRENT, PRIORITY_SYSTEM);
 #endif
@@ -234,6 +236,26 @@ static void usb_thread(void)
                     (struct usb_transfer_completion_event_data*)ev.data);
                 break;
 #endif
+#ifdef USB_DETECT_BY_DRV
+            /* In this case, these events the handle cable insertion USB
+             * driver determines INSERTED/EXTRACTED state. */
+            case USB_POWERED:
+                /* Set the state to USB_POWERED for now and enable the driver
+                 * to detect a bus reset only. If a bus reset is detected,
+                 * USB_INSERTED will be received. */
+                usb_state = USB_POWERED;
+                usb_enable(true);
+                break;
+
+            case USB_UNPOWERED:
+                usb_enable(false);
+                /* This part shouldn't be obligatory for anything that can
+                 * reliably detect removal of the data lines. USB_EXTRACTED
+                 * could be posted on that event while bus power remains
+                 * available. */
+                queue_post(&usb_queue, USB_EXTRACTED, 0);
+                break;
+#endif /* USB_DETECT_BY_DRV */
             case USB_INSERTED:
 #ifdef HAVE_LCD_BITMAP
                 if(do_screendump_instead_of_usb)
@@ -244,14 +266,14 @@ static void usb_thread(void)
                 }
 #endif
 #ifdef HAVE_USB_POWER
-                if (usb_power_button())
+                if(usb_power_button())
                 {
                     /* Only charging is desired */
                     usb_state = USB_POWERED;
 #ifdef HAVE_USBSTACK
                     usb_core_enable_driver(USB_DRIVER_MASS_STORAGE, false);
                     usb_core_enable_driver(USB_DRIVER_CHARGING_ONLY, true);
-                    usb_enable(true);
+                    usb_attach();
 #endif
                     break;
                 }
@@ -272,7 +294,7 @@ static void usb_thread(void)
 
                 if(!exclusive_storage_access)
                 {
-                    usb_enable(true);
+                    usb_attach();
                     break;
                 }
 #endif /* HAVE_USBSTACK */
@@ -304,7 +326,7 @@ static void usb_thread(void)
                     usb_state = USB_EXTRACTED;
                     break; /* Connected for screendump only */
                 }
-#endif /* HAVE_LCD_BITMAP */
+#endif
 #ifndef HAVE_USBSTACK /* Stack must undo this if POWERED state was transitional */
 #ifdef HAVE_USB_POWER
                 if(usb_state == USB_POWERED)
@@ -312,7 +334,7 @@ static void usb_thread(void)
                     usb_state = USB_EXTRACTED;
                     break;
                 }
-#endif /* HAVE_USB_POWER */
+#endif
 #endif /* HAVE_USBSTACK */
                 if(usb_state == USB_INSERTED)
                 {
@@ -324,9 +346,11 @@ static void usb_thread(void)
 
                 usb_state = USB_EXTRACTED;
 #ifdef HAVE_USBSTACK
-                if (!exclusive_storage_access)
+                if(!exclusive_storage_access)
                 {
+#ifndef USB_DETECT_BY_DRV /* Disabled handling USB_UNPOWERED */
                     usb_enable(false);
+#endif
                     break;
                 }
 
@@ -392,19 +416,34 @@ static void usb_thread(void)
 #ifdef USB_STATUS_BY_EVENT
 void usb_status_event(int current_status)
 {
-    /* Status should be USB_INSERTED or USB_EXTRACTED.
+    /* Status should be USB_POWERED, USB_UNPOWERED, USB_INSERTED or
+     * USB_EXTRACTED.
      * Caller isn't expected to filter for changes in status. */
-    if (usb_monitor_enabled && last_usb_status != current_status)
+    if(usb_monitor_enabled)
     {
-        last_usb_status = current_status;
-        queue_post(&usb_queue, current_status, 0);
+        int oldstatus = disable_irq_save(); /* Dual-use function */
+
+        if(last_usb_status != current_status)
+        {
+            last_usb_status = current_status;
+            queue_post(&usb_queue, current_status, 0);
+        }
+
+        restore_irq(oldstatus);
     }
 }
 
 void usb_start_monitoring(void)
 {
+    int status = usb_detect();
+#ifdef USB_DETECT_BY_DRV
+    /* USB detection begins by USB_POWERED, not USB_INSERTED. If it is
+     * USB_EXTRACTED, then nothing changes and post will be skipped. */
+    if(USB_INSERTED == status)
+        status = USB_POWERED;
+#endif
     usb_monitor_enabled = true;
-    usb_status_event(usb_detect());
+    usb_status_event(status);
 }
 #else /* !USB_STATUS_BY_EVENT */
 static void usb_tick(void)
diff --git a/firmware/usbstack/usb_core.c b/firmware/usbstack/usb_core.c
index 50c9d85..5fac5d3 100644
--- a/firmware/usbstack/usb_core.c
+++ b/firmware/usbstack/usb_core.c
@@ -175,7 +175,7 @@ static struct
     completion_handler_t completion_handler[2];
     control_handler_t control_handler[2];
     struct usb_transfer_completion_event_data completion_event;
-} ep_data[NUM_ENDPOINTS];
+} ep_data[USB_NUM_ENDPOINTS];
 
 static struct usb_class_driver drivers[USB_NUM_DRIVERS] =
 {
@@ -240,7 +240,7 @@ static struct usb_class_driver drivers[USB_NUM_DRIVERS] =
 
 static void usb_core_control_request_handler(struct usb_ctrlrequest* req);
 
-static unsigned char response_data[256] USBDEVBSS_ATTR;
+static unsigned char response_data[256] USB_DEVBSS_ATTR;
 
 
 static short hex[16] = {'0','1','2','3','4','5','6','7',
@@ -476,7 +476,7 @@ static void allocate_interfaces_and_endpoints(void)
 
     memset(ep_data,0,sizeof(ep_data));
 
-    for (i = 0; i < NUM_ENDPOINTS; i++) {
+    for (i = 0; i < USB_NUM_ENDPOINTS; i++) {
         usb_drv_release_endpoint(i | USB_DIR_OUT);
         usb_drv_release_endpoint(i | USB_DIR_IN);
     }
diff --git a/firmware/usbstack/usb_storage.c b/firmware/usbstack/usb_storage.c
index a70681d..e2d58cf 100644
--- a/firmware/usbstack/usb_storage.c
+++ b/firmware/usbstack/usb_storage.c
@@ -401,7 +401,7 @@ void usb_storage_init_connection(void)
 #if CONFIG_CPU == IMX31L || CONFIG_USBOTG == USBOTG_ISP1583 || \
         defined(CPU_TCC77X) || defined(CPU_TCC780X)
     static unsigned char _transfer_buffer[BUFFER_SIZE*2]
-        USBDEVBSS_ATTR __attribute__((aligned(32)));
+        USB_DEVBSS_ATTR __attribute__((aligned(32)));
     tb.transfer_buffer = (void *)_transfer_buffer;
 #else
     /* TODO : check if bufsize is at least 32K ? */