The errata2 workaround is described in the Datasheet as follows:
An SOF INT can be used instead of an ATL INT with polling on Done
bits. A time-out can be implemented and if a certain Done bit is never
set, verification of the PTD completion can be done by reading PTD
contents (valid bit). This is a proven workaround implemented in
software.
Therefore, we should do so, and ignore the check
for the ACTIVE_BIT in DW3. Because it is possible
that this bit is still set when the issue accures.
Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
---
drivers/usb/host/isp1760-hcd.c | 110 +++++++++++++++++-----------------------
drivers/usb/host/isp1760-hcd.h | 1 +
2 files changed, 48 insertions(+), 63 deletions(-)
diff --git a/drivers/usb/host/isp1760-hcd.c b/drivers/usb/host/isp1760-hcd.c
index 90c57dc..4beedba 100644
--- a/drivers/usb/host/isp1760-hcd.c
+++ b/drivers/usb/host/isp1760-hcd.c
@@ -48,6 +48,8 @@ struct isp1760_hcd {
int int_done_map;
struct memory_chunk memory_pool[BLOCKS];
struct list_head qh_list[QH_END];
+ int active_ptds;
+ int last_active_ptds;
/* periodic schedule support */
#define DEFAULT_I_TDPS 1024
@@ -512,6 +514,11 @@ static int isp1760_hc_setup(struct usb_hcd *hcd)
16 : 32, (priv->devflags & ISP1760_FLAG_ANALOG_OC) ?
"analog" : "digital");
+ /* This is weird: at the first plug-in of a device there seems to be
+ one packet queued that never gets returned? */
+ priv->active_ptds = -1;
+ priv->last_active_ptds = 0;
+
/* ATL reset */
reg_write32(hcd->regs, HC_HW_MODE_CTRL, hwmode | ALL_ATX_RESET);
mdelay(10);
@@ -775,6 +782,7 @@ static void start_bus_transfer(struct usb_hcd *hcd, u32 ptd_offset, int slot,
slots[slot].qtd = qtd;
slots[slot].qh = qh;
ptd_write(hcd->regs, ptd_offset, slot, ptd);
+ priv->active_ptds++;
if (ptd_offset == ATL_PTD_OFFSET) {
skip_map = reg_read32(hcd->regs, HC_ATL_PTD_SKIPMAP_REG);
@@ -1147,6 +1155,7 @@ static void handle_done_ptds(struct usb_hcd *hcd)
slots[slot].qtd = NULL;
qh = slots[slot].qh;
slots[slot].qh = NULL;
+ priv->active_ptds--;
qh->slot = -1;
WARN_ON(qtd->status != QTD_XFER_STARTED);
@@ -1228,10 +1237,13 @@ static void handle_done_ptds(struct usb_hcd *hcd)
schedule_ptds(hcd);
}
+#define SLOT_TIMEOUT 300
static irqreturn_t isp1760_irq(struct usb_hcd *hcd)
{
struct isp1760_hcd *priv = hcd_to_priv(hcd);
u32 imask;
+ int slot;
+ struct ptd ptd;
irqreturn_t irqret = IRQ_NONE;
spin_lock(&priv->lock);
@@ -1247,71 +1259,50 @@ static irqreturn_t isp1760_irq(struct usb_hcd *hcd)
priv->int_done_map |= reg_read32(hcd->regs, HC_INT_PTD_DONEMAP_REG);
priv->atl_done_map |= reg_read32(hcd->regs, HC_ATL_PTD_DONEMAP_REG);
- handle_done_ptds(hcd);
-
- irqret = IRQ_HANDLED;
-leave:
- spin_unlock(&priv->lock);
-
- return irqret;
-}
-
-/*
- * Workaround for problem described in chip errata 2:
- *
- * Sometimes interrupts are not generated when ATL (not INT?) completion occurs.
- * One solution suggested in the errata is to use SOF interrupts _instead_of_
- * ATL done interrupts (the "instead of" might be important since it seems
- * enabling ATL interrupts also causes the chip to sometimes - rarely - "forget"
- * to set the PTD's done bit in addition to not generating an interrupt!).
- *
- * So if we use SOF + ATL interrupts, we sometimes get stale PTDs since their
- * done bit is not being set. This is bad - it blocks the endpoint until reboot.
- *
- * If we use SOF interrupts only, we get latency between ptd completion and the
- * actual handling. This is very noticeable in testusb runs which takes several
- * minutes longer without ATL interrupts.
- *
- * A better solution is to run the code below every SLOT_CHECK_PERIOD ms. If it
- * finds active ATL slots which are older than SLOT_TIMEOUT ms, it checks the
- * slot's ACTIVE and VALID bits. If these are not set, the ptd is considered
- * completed and its done map bit is set.
- *
- * The values of SLOT_TIMEOUT and SLOT_CHECK_PERIOD have been arbitrarily chosen
- * not to cause too much lag when this HW bug occurs, while still hopefully
- * ensuring that the check does not falsely trigger.
- */
-#define SLOT_TIMEOUT 300
-#define SLOT_CHECK_PERIOD 200
-static struct timer_list errata2_timer;
-
-void errata2_function(unsigned long data)
-{
- struct usb_hcd *hcd = (struct usb_hcd *) data;
- struct isp1760_hcd *priv = hcd_to_priv(hcd);
- int slot;
- struct ptd ptd;
- unsigned long spinflags;
-
- spin_lock_irqsave(&priv->lock, spinflags);
+ /* Errata2: A time-out can be implemented and if a certain Done bit is
+ never set, verification of the PTD completion is done by reading PTD
+ contents (valid bit). This is a proven workaround implemented in
+ software. */
for (slot = 0; slot < 32; slot++)
if (priv->atl_slots[slot].qh && time_after(jiffies,
priv->atl_slots[slot].timestamp +
- SLOT_TIMEOUT * HZ / 1000)) {
+ msecs_to_jiffies(SLOT_TIMEOUT)) &&
+ !(priv->atl_done_map & (1 << slot))) {
ptd_read(hcd->regs, ATL_PTD_OFFSET, slot, &ptd);
- if (!FROM_DW0_VALID(ptd.dw0) &&
- !FROM_DW3_ACTIVE(ptd.dw3))
+
+ priv->atl_slots[slot].timestamp = jiffies;
+ if (!FROM_DW0_VALID(ptd.dw0)) {
priv->atl_done_map |= 1 << slot;
+ dev_info(hcd->self.controller, "errata2 issue!\n");
+ continue;
+ }
}
- if (priv->atl_done_map)
- handle_done_ptds(hcd);
- spin_unlock_irqrestore(&priv->lock, spinflags);
+ handle_done_ptds(hcd);
- errata2_timer.expires = jiffies + SLOT_CHECK_PERIOD * HZ / 1000;
- add_timer(&errata2_timer);
+ /* ISP1760 Errata 2 explains that interrupts may be missed (or not
+ happen?) if two USB devices are running simultaneously. Perhaps
+ this happens when a PTD is finished during interrupt handling;
+ enable SOF interrupts if PTDs are still scheduled when exiting this
+ interrupt handler, just to be safe. */
+
+ if (priv->active_ptds != priv->last_active_ptds) {
+ if (priv->active_ptds > 0)
+ reg_write32(hcd->regs, HC_INTERRUPT_ENABLE,
+ INTERRUPT_ENABLE_SOT_MASK);
+ else
+ reg_write32(hcd->regs, HC_INTERRUPT_ENABLE,
+ INTERRUPT_ENABLE_MASK);
+ priv->last_active_ptds = priv->active_ptds;
+ }
+
+ irqret = IRQ_HANDLED;
+leave:
+ spin_unlock(&priv->lock);
+
+ return irqret;
}
static int isp1760_run(struct usb_hcd *hcd)
@@ -1359,12 +1350,6 @@ static int isp1760_run(struct usb_hcd *hcd)
if (retval)
return retval;
- init_timer(&errata2_timer);
- errata2_timer.function = errata2_function;
- errata2_timer.data = (unsigned long) hcd;
- errata2_timer.expires = jiffies + SLOT_CHECK_PERIOD * HZ / 1000;
- add_timer(&errata2_timer);
-
chipid = reg_read32(hcd->regs, HC_CHIP_ID_REG);
dev_info(hcd->self.controller, "USB ISP %04x HW rev. %d started\n",
chipid & 0xffff, chipid >> 16);
@@ -1627,6 +1612,7 @@ static void kill_transfer(struct usb_hcd *hcd, struct urb *urb,
}
qh->slot = -1;
+ priv->active_ptds--;
}
/*
@@ -2113,8 +2099,6 @@ static void isp1760_stop(struct usb_hcd *hcd)
struct isp1760_hcd *priv = hcd_to_priv(hcd);
u32 temp;
- del_timer(&errata2_timer);
-
isp1760_hub_control(hcd, ClearPortFeature, USB_PORT_FEAT_POWER, 1,
NULL, 0);
mdelay(20);
diff --git a/drivers/usb/host/isp1760-hcd.h b/drivers/usb/host/isp1760-hcd.h
index 33dc79c..b20ae45 100644
--- a/drivers/usb/host/isp1760-hcd.h
+++ b/drivers/usb/host/isp1760-hcd.h
@@ -74,6 +74,7 @@ void deinit_kmem_cache(void);
#define HC_EOT_INT (1 << 3)
#define HC_SOT_INT (1 << 1)
#define INTERRUPT_ENABLE_MASK (HC_INTL_INT | HC_ATL_INT)
+#define INTERRUPT_ENABLE_SOT_MASK (HC_SOT_INT)
#define HC_ISO_IRQ_MASK_OR_REG 0x318
#define HC_INT_IRQ_MASK_OR_REG 0x31C
--
1.7.10
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