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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2011-02-08 21:07:40 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-02-17 10:47:55 -0800
commitb14e840d04dba211fbdc930247e379085623eacd (patch)
tree8b57a59f211b3304fe8e10a7c8a23791b11771d3
parent4f9e6c64d1fc4668f3153f456b41cf40b30c730f (diff)
USB: isp1760: Implement solution for erratum 2
The document says: |2.1 Problem description | When at least two USB devices are simultaneously running, it is observed that | sometimes the INT corresponding to one of the USB devices stops occurring. This may | be observed sometimes with USB-to-serial or USB-to-network devices. | The problem is not noticed when only USB mass storage devices are running. |2.2 Implication | This issue is because of the clearing of the respective Done Map bit on reading the ATL | PTD Done Map register when an INT is generated by another PTD completion, but is not | found set on that read access. In this situation, the respective Done Map bit will remain | reset and no further INT will be asserted so the data transfer corresponding to that USB | device will stop. |2.3 Workaround | 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. Russell King run into this with an USB-to-serial converter. This patch implements his suggestion to enable the high frequent SOF interrupt only at the time we have ATL packages queued. It goes even one step further and enables the SOF interrupt only if we have more than one ATL packet queued at the same time. Cc: <stable@kernel.org> # [2.6.35.x, 2.6.36.x, 2.6.37.x] Tested-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/host/isp1760-hcd.c22
-rw-r--r--drivers/usb/host/isp1760-hcd.h1
2 files changed, 17 insertions, 6 deletions
diff --git a/drivers/usb/host/isp1760-hcd.c b/drivers/usb/host/isp1760-hcd.c
index bdba8c5d844..c470cc83dbb 100644
--- a/drivers/usb/host/isp1760-hcd.c
+++ b/drivers/usb/host/isp1760-hcd.c
@@ -33,6 +33,7 @@ struct isp1760_hcd {
struct inter_packet_info atl_ints[32];
struct inter_packet_info int_ints[32];
struct memory_chunk memory_pool[BLOCKS];
+ u32 atl_queued;
/* periodic schedule support */
#define DEFAULT_I_TDPS 1024
@@ -850,6 +851,11 @@ static void enqueue_an_ATL_packet(struct usb_hcd *hcd, struct isp1760_qh *qh,
skip_map &= ~queue_entry;
isp1760_writel(skip_map, hcd->regs + HC_ATL_PTD_SKIPMAP_REG);
+ priv->atl_queued++;
+ if (priv->atl_queued == 2)
+ isp1760_writel(INTERRUPT_ENABLE_SOT_MASK,
+ hcd->regs + HC_INTERRUPT_ENABLE);
+
buffstatus = isp1760_readl(hcd->regs + HC_BUFFER_STATUS_REG);
buffstatus |= ATL_BUFFER;
isp1760_writel(buffstatus, hcd->regs + HC_BUFFER_STATUS_REG);
@@ -992,6 +998,7 @@ static void do_atl_int(struct usb_hcd *usb_hcd)
u32 dw3;
status = 0;
+ priv->atl_queued--;
queue_entry = __ffs(done_map);
done_map &= ~(1 << queue_entry);
@@ -1054,11 +1061,6 @@ static void do_atl_int(struct usb_hcd *usb_hcd)
* device is not able to send data fast enough.
* This happens mostly on slower hardware.
*/
- printk(KERN_NOTICE "Reloading ptd %p/%p... qh %p read: "
- "%d of %zu done: %08x cur: %08x\n", qtd,
- urb, qh, PTD_XFERRED_LENGTH(dw3),
- qtd->length, done_map,
- (1 << queue_entry));
/* RL counter = ERR counter */
dw3 &= ~(0xf << 19);
@@ -1086,6 +1088,11 @@ static void do_atl_int(struct usb_hcd *usb_hcd)
priv_write_copy(priv, (u32 *)&ptd, usb_hcd->regs +
atl_regs, sizeof(ptd));
+ priv->atl_queued++;
+ if (priv->atl_queued == 2)
+ isp1760_writel(INTERRUPT_ENABLE_SOT_MASK,
+ usb_hcd->regs + HC_INTERRUPT_ENABLE);
+
buffstatus = isp1760_readl(usb_hcd->regs +
HC_BUFFER_STATUS_REG);
buffstatus |= ATL_BUFFER;
@@ -1191,6 +1198,9 @@ static void do_atl_int(struct usb_hcd *usb_hcd)
skip_map = isp1760_readl(usb_hcd->regs +
HC_ATL_PTD_SKIPMAP_REG);
}
+ if (priv->atl_queued <= 1)
+ isp1760_writel(INTERRUPT_ENABLE_MASK,
+ usb_hcd->regs + HC_INTERRUPT_ENABLE);
}
static void do_intl_int(struct usb_hcd *usb_hcd)
@@ -1770,7 +1780,7 @@ static irqreturn_t isp1760_irq(struct usb_hcd *usb_hcd)
goto leave;
isp1760_writel(imask, usb_hcd->regs + HC_INTERRUPT_REG);
- if (imask & HC_ATL_INT)
+ if (imask & (HC_ATL_INT | HC_SOT_INT))
do_atl_int(usb_hcd);
if (imask & HC_INTL_INT)
diff --git a/drivers/usb/host/isp1760-hcd.h b/drivers/usb/host/isp1760-hcd.h
index 6931ef5c965..612bce5dce0 100644
--- a/drivers/usb/host/isp1760-hcd.h
+++ b/drivers/usb/host/isp1760-hcd.h
@@ -69,6 +69,7 @@ void deinit_kmem_cache(void);
#define HC_INTERRUPT_ENABLE 0x314
#define INTERRUPT_ENABLE_MASK (HC_INTL_INT | HC_ATL_INT | HC_EOT_INT)
+#define INTERRUPT_ENABLE_SOT_MASK (HC_INTL_INT | HC_SOT_INT | HC_EOT_INT)
#define HC_ISO_INT (1 << 9)
#define HC_ATL_INT (1 << 8)