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zd1211rw: handle lost read-reg interrupts 

Device losses read-reg interrupts. By looking at usbmon it appears that
USB_INT_ID_RETRY_FAILED can override USB_INT_ID_REGS. This causes read
command to timeout, usually under heavy TX.

Fix by retrying read registers again if USB_INT_ID_RETRY_FAILED is received
while waiting for USB_INT_ID_REGS.

However USB_INT_ID_REGS is not always lost but is received after
USB_INT_ID_RETRY_FAILED and is usually received by the retried read
command. USB_INT_ID_REGS of the retry is then left unhandled and might
be received by next read command. Handle this by ignoring previous
USB_INT_ID_REGS that doesn't match current read command request.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Jussi Kivilinna 2011-06-20 14:42:44 +03:00 committed by John W. Linville
parent f762d8c3f8
commit c900eff30a
2 changed files with 120 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

147
drivers/net/wireless/zd1211rw/zd_usb.c
View File

@ -111,6 +111,9 @@ MODULE_DEVICE_TABLE(usb, usb_ids);
#define FW_ZD1211_PREFIX "zd1211/zd1211_"
#define FW_ZD1211B_PREFIX "zd1211/zd1211b_"
static bool check_read_regs(struct zd_usb *usb, struct usb_req_read_regs *req,
unsigned int count);
/* USB device initialization */
static void int_urb_complete(struct urb *urb);
@ -365,6 +368,20 @@ int zd_usb_read_fw(struct zd_usb *usb, zd_addr_t addr, u8 *data, u16 len)
#define urb_dev(urb) (&(urb)->dev->dev)
static inline void handle_regs_int_override(struct urb *urb)
{
struct zd_usb *usb = urb->context;
struct zd_usb_interrupt *intr = &usb->intr;
spin_lock(&intr->lock);
if (atomic_read(&intr->read_regs_enabled)) {
atomic_set(&intr->read_regs_enabled, 0);
intr->read_regs_int_overridden = 1;
complete(&intr->read_regs.completion);
}
spin_unlock(&intr->lock);
}
static inline void handle_regs_int(struct urb *urb)
{
struct zd_usb *usb = urb->context;
@ -383,25 +400,45 @@ static inline void handle_regs_int(struct urb *urb)
USB_MAX_EP_INT_BUFFER);
spin_unlock(&mac->lock);
schedule_work(&mac->process_intr);
} else if (intr->read_regs_enabled) {
intr->read_regs.length = len = urb->actual_length;
} else if (atomic_read(&intr->read_regs_enabled)) {
len = urb->actual_length;
intr->read_regs.length = urb->actual_length;
if (len > sizeof(intr->read_regs.buffer))
len = sizeof(intr->read_regs.buffer);
memcpy(intr->read_regs.buffer, urb->transfer_buffer, len);
intr->read_regs_enabled = 0;
/* Sometimes USB_INT_ID_REGS is not overridden, but comes after
* USB_INT_ID_RETRY_FAILED. Read-reg retry then gets this
* delayed USB_INT_ID_REGS, but leaves USB_INT_ID_REGS of
* retry unhandled. Next read-reg command then might catch
* this wrong USB_INT_ID_REGS. Fix by ignoring wrong reads.
*/
if (!check_read_regs(usb, intr->read_regs.req,
intr->read_regs.req_count))
goto out;
atomic_set(&intr->read_regs_enabled, 0);
intr->read_regs_int_overridden = 0;
complete(&intr->read_regs.completion);
goto out;
}
out:
spin_unlock(&intr->lock);
/* CR_INTERRUPT might override read_reg too. */
if (int_num == CR_INTERRUPT && atomic_read(&intr->read_regs_enabled))
handle_regs_int_override(urb);
}
static void int_urb_complete(struct urb *urb)
{
int r;
struct usb_int_header *hdr;
struct zd_usb *usb;
struct zd_usb_interrupt *intr;
switch (urb->status) {
case 0:
@ -430,6 +467,14 @@ static void int_urb_complete(struct urb *urb)
goto resubmit;
}
/* USB_INT_ID_RETRY_FAILED triggered by tx-urb submit can override
* pending USB_INT_ID_REGS causing read command timeout.
*/
usb = urb->context;
intr = &usb->intr;
if (hdr->id != USB_INT_ID_REGS && atomic_read(&intr->read_regs_enabled))
handle_regs_int_override(urb);
switch (hdr->id) {
case USB_INT_ID_REGS:
handle_regs_int(urb);
@ -1129,6 +1174,7 @@ static inline void init_usb_interrupt(struct zd_usb *usb)
spin_lock_init(&intr->lock);
intr->interval = int_urb_interval(zd_usb_to_usbdev(usb));
init_completion(&intr->read_regs.completion);
atomic_set(&intr->read_regs_enabled, 0);
intr->read_regs.cr_int_addr = cpu_to_le16((u16)CR_INTERRUPT);
}
@ -1563,12 +1609,16 @@ static int usb_int_regs_length(unsigned int count)
return sizeof(struct usb_int_regs) + count * sizeof(struct reg_data);
}
static void prepare_read_regs_int(struct zd_usb *usb)
static void prepare_read_regs_int(struct zd_usb *usb,
struct usb_req_read_regs *req,
unsigned int count)
{
struct zd_usb_interrupt *intr = &usb->intr;
spin_lock_irq(&intr->lock);
intr->read_regs_enabled = 1;
atomic_set(&intr->read_regs_enabled, 1);
intr->read_regs.req = req;
intr->read_regs.req_count = count;
INIT_COMPLETION(intr->read_regs.completion);
spin_unlock_irq(&intr->lock);
}
@ -1578,12 +1628,52 @@ static void disable_read_regs_int(struct zd_usb *usb)
struct zd_usb_interrupt *intr = &usb->intr;
spin_lock_irq(&intr->lock);
intr->read_regs_enabled = 0;
atomic_set(&intr->read_regs_enabled, 0);
spin_unlock_irq(&intr->lock);
}
static bool check_read_regs(struct zd_usb *usb, struct usb_req_read_regs *req,
unsigned int count)
{
int i;
struct zd_usb_interrupt *intr = &usb->intr;
struct read_regs_int *rr = &intr->read_regs;
struct usb_int_regs *regs = (struct usb_int_regs *)rr->buffer;
/* The created block size seems to be larger than expected.
* However results appear to be correct.
*/
if (rr->length < usb_int_regs_length(count)) {
dev_dbg_f(zd_usb_dev(usb),
"error: actual length %d less than expected %d\n",
rr->length, usb_int_regs_length(count));
return false;
}
if (rr->length > sizeof(rr->buffer)) {
dev_dbg_f(zd_usb_dev(usb),
"error: actual length %d exceeds buffer size %zu\n",
rr->length, sizeof(rr->buffer));
return false;
}
for (i = 0; i < count; i++) {
struct reg_data *rd = &regs->regs[i];
if (rd->addr != req->addr[i]) {
dev_dbg_f(zd_usb_dev(usb),
"rd[%d] addr %#06hx expected %#06hx\n", i,
le16_to_cpu(rd->addr),
le16_to_cpu(req->addr[i]));
return false;
}
}
return true;
}
static int get_results(struct zd_usb *usb, u16 *values,
struct usb_req_read_regs *req, unsigned int count)
struct usb_req_read_regs *req, unsigned int count,
bool *retry)
{
int r;
int i;
@ -1594,31 +1684,19 @@ static int get_results(struct zd_usb *usb, u16 *values,
spin_lock_irq(&intr->lock);
r = -EIO;
/* The created block size seems to be larger than expected.
* However results appear to be correct.
*/
if (rr->length < usb_int_regs_length(count)) {
dev_dbg_f(zd_usb_dev(usb),
"error: actual length %d less than expected %d\n",
rr->length, usb_int_regs_length(count));
/* Read failed because firmware bug? */
*retry = !!intr->read_regs_int_overridden;
if (*retry)
goto error_unlock;
}
if (rr->length > sizeof(rr->buffer)) {
dev_dbg_f(zd_usb_dev(usb),
"error: actual length %d exceeds buffer size %zu\n",
rr->length, sizeof(rr->buffer));
if (!check_read_regs(usb, req, count)) {
dev_dbg_f(zd_usb_dev(usb), "error: invalid read regs\n");
goto error_unlock;
}
for (i = 0; i < count; i++) {
struct reg_data *rd = &regs->regs[i];
if (rd->addr != req->addr[i]) {
dev_dbg_f(zd_usb_dev(usb),
"rd[%d] addr %#06hx expected %#06hx\n", i,
le16_to_cpu(rd->addr),
le16_to_cpu(req->addr[i]));
goto error_unlock;
}
values[i] = le16_to_cpu(rd->value);
}
@ -1631,11 +1709,11 @@ static int get_results(struct zd_usb *usb, u16 *values,
int zd_usb_ioread16v(struct zd_usb *usb, u16 *values,
const zd_addr_t *addresses, unsigned int count)
{
int r;
int i, req_len, actual_req_len;
int r, i, req_len, actual_req_len, try_count = 0;
struct usb_device *udev;
struct usb_req_read_regs *req = NULL;
unsigned long timeout;
bool retry = false;
if (count < 1) {
dev_dbg_f(zd_usb_dev(usb), "error: count is zero\n");
@ -1671,8 +1749,10 @@ int zd_usb_ioread16v(struct zd_usb *usb, u16 *values,
for (i = 0; i < count; i++)
req->addr[i] = cpu_to_le16((u16)addresses[i]);
retry_read:
try_count++;
udev = zd_usb_to_usbdev(usb);
prepare_read_regs_int(usb);
prepare_read_regs_int(usb, req, count);
r = zd_ep_regs_out_msg(udev, req, req_len, &actual_req_len, 50 /*ms*/);
if (r) {
dev_dbg_f(zd_usb_dev(usb),
@ -1696,7 +1776,12 @@ int zd_usb_ioread16v(struct zd_usb *usb, u16 *values,
goto error;
}
r = get_results(usb, values, req, count);
r = get_results(usb, values, req, count, &retry);
if (retry && try_count < 20) {
dev_dbg_f(zd_usb_dev(usb), "read retry, tries so far: %d\n",
try_count);
goto retry_read;
}
error:
return r;
}

5
drivers/net/wireless/zd1211rw/zd_usb.h
View File

@ -144,6 +144,8 @@ struct usb_int_retry_fail {
struct read_regs_int {
struct completion completion;
struct usb_req_read_regs *req;
unsigned int req_count;
/* Stores the USB int structure and contains the USB address of the
* first requested register before request.
*/
@ -169,7 +171,8 @@ struct zd_usb_interrupt {
void *buffer;
dma_addr_t buffer_dma;
int interval;
u8 read_regs_enabled:1;
atomic_t read_regs_enabled;
u8 read_regs_int_overridden:1;
};
static inline struct usb_int_regs *get_read_regs(struct zd_usb_interrupt *intr)