Hi! Please hold on in merging this series, because I have to investigate a hint I got related to the buffer size handshake of the protocol driver: https://www.linuxtv.org/pipermail/linux-dvb/2007-July/019116.html BR, Jasmin On 12/21/2017 02:22 PM, Jasmin J. wrote: > From: Jasmin Jessich <jasmin@xxxxxx> > > Some (older) CAMs are really slow in accepting data. The CI interface > specification doesn't define a handshake for accepted data. Thus, the > en50221 protocol driver can't control if a data byte has been correctly > written to the CAM. > > The current implementation writes the length and the data quick after > each other. Thus, the slow CAMs may generate a WR error, which leads to > the known error logging > "CAM tried to send a buffer larger than the ecount size". > > To solve this issue the en50221 protocol driver needs to wait some CAM > depending time between the different bytes to be written. Because the > time is CAM dependent, an individual value per CAM needs to be set. For > that SysFS is used in favor of ioctl's to allow the control of the timer > values independent from any user space application. > > This patch adds the timers and the SysFS nodes to set/get the timeout > values and the timer waiting between the different steps of the CAM write > access. A timer value of 0 (default) means "no timeout". > > Signed-off-by: Jasmin Jessich <jasmin@xxxxxx> > Acked-by: Ralph Metzler <rjkm@xxxxxxxxxxxxxx> > --- > drivers/media/dvb-core/dvb_ca_en50221.c | 132 +++++++++++++++++++++++++++++++- > 1 file changed, 131 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/dvb-core/dvb_ca_en50221.c b/drivers/media/dvb-core/dvb_ca_en50221.c > index a3b2754..9b45d6b 100644 > --- a/drivers/media/dvb-core/dvb_ca_en50221.c > +++ b/drivers/media/dvb-core/dvb_ca_en50221.c > @@ -86,6 +86,13 @@ MODULE_PARM_DESC(cam_debug, "enable verbose debug messages"); > #define DVB_CA_SLOTSTATE_WAITFR 6 > #define DVB_CA_SLOTSTATE_LINKINIT 7 > > +enum dvb_ca_timers { > + DVB_CA_TIM_WR_HIGH /* wait after writing length high */ > +, DVB_CA_TIM_WR_LOW /* wait after writing length low */ > +, DVB_CA_TIM_WR_DATA /* wait between data bytes */ > +, DVB_CA_TIM_MAX > +}; > + > /* Information on a CA slot */ > struct dvb_ca_slot { > /* current state of the CAM */ > @@ -119,6 +126,11 @@ struct dvb_ca_slot { > unsigned long timeout; > }; > > +struct dvb_ca_timer { > + unsigned long min; > + unsigned long max; > +}; > + > /* Private CA-interface information */ > struct dvb_ca_private { > struct kref refcount; > @@ -161,6 +173,14 @@ struct dvb_ca_private { > > /* mutex serializing ioctls */ > struct mutex ioctl_mutex; > + > + struct dvb_ca_timer timers[DVB_CA_TIM_MAX]; > +}; > + > +static const char dvb_ca_tim_names[DVB_CA_TIM_MAX][15] = { > + "tim_wr_high" > +, "tim_wr_low" > +, "tim_wr_data" > }; > > static void dvb_ca_private_free(struct dvb_ca_private *ca) > @@ -223,6 +243,14 @@ static char *findstr(char *haystack, int hlen, char *needle, int nlen) > return NULL; > } > > +static void dvb_ca_sleep(struct dvb_ca_private *ca, enum dvb_ca_timers tim) > +{ > + unsigned long min = ca->timers[tim].min; > + > + if (min) > + usleep_range(min, ca->timers[tim].max); > +} > + > /* ************************************************************************** */ > /* EN50221 physical interface functions */ > > @@ -869,10 +897,13 @@ static int dvb_ca_en50221_write_data(struct dvb_ca_private *ca, int slot, > bytes_write >> 8); > if (status) > goto exit; > + dvb_ca_sleep(ca, DVB_CA_TIM_WR_HIGH); > + > status = ca->pub->write_cam_control(ca->pub, slot, CTRLIF_SIZE_LOW, > bytes_write & 0xff); > if (status) > goto exit; > + dvb_ca_sleep(ca, DVB_CA_TIM_WR_LOW); > > /* send the buffer */ > for (i = 0; i < bytes_write; i++) { > @@ -880,6 +911,7 @@ static int dvb_ca_en50221_write_data(struct dvb_ca_private *ca, int slot, > buf[i]); > if (status) > goto exit; > + dvb_ca_sleep(ca, DVB_CA_TIM_WR_DATA); > } > > /* check for write error (WE should now be 0) */ > @@ -1834,6 +1866,97 @@ static const struct dvb_device dvbdev_ca = { > }; > > /* ************************************************************************** */ > +/* EN50221 device attributes (SysFS) */ > + > +static int dvb_ca_tim_idx(struct dvb_ca_private *ca, const char *name) > +{ > + int tim_idx; > + > + for (tim_idx = 0; tim_idx < DVB_CA_TIM_MAX; tim_idx++) { > + if (!strcmp(dvb_ca_tim_names[tim_idx], name)) > + return tim_idx; > + } > + return -1; > +} > + > +static ssize_t dvb_ca_tim_show(struct device *device, > + struct device_attribute *attr, char *buf) > +{ > + struct dvb_device *dvbdev = dev_get_drvdata(device); > + struct dvb_ca_private *ca = dvbdev->priv; > + int tim_idx = dvb_ca_tim_idx(ca, attr->attr.name); > + > + if (tim_idx < 0) > + return -ENXIO; > + > + return sprintf(buf, "%ld\n", ca->timers[tim_idx].min); > +} > + > +static ssize_t dvb_ca_tim_store(struct device *device, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct dvb_device *dvbdev = dev_get_drvdata(device); > + struct dvb_ca_private *ca = dvbdev->priv; > + int tim_idx = dvb_ca_tim_idx(ca, attr->attr.name); > + unsigned long min, max; > + > + if (tim_idx < 0) > + return -ENXIO; > + > + if (sscanf(buf, "%lu\n", &min) != 1) > + return -EINVAL; > + > + /* value is in us; 100ms is a good maximum */ > + if (min > (100 * USEC_PER_MSEC)) > + return -EINVAL; > + > + /* +10% (rounded up) */ > + max = (min * 11 + 5) / 10; > + ca->timers[tim_idx].min = min; > + ca->timers[tim_idx].max = max; > + > + return count; > +} > + > +/* attribute definition with string pointer (see include/linux/sysfs.h) */ > +#define DVB_CA_ATTR(_name, _mode, _show, _store) { \ > + .attr = {.name = _name, .mode = _mode }, \ > + .show = _show, \ > + .store = _store, \ > +} > + > +#define DVB_CA_ATTR_TIM(_tim_idx) \ > + DVB_CA_ATTR(dvb_ca_tim_names[_tim_idx], 0664, dvb_ca_tim_show, \ > + dvb_ca_tim_store) > + > +static const struct device_attribute dvb_ca_attrs[DVB_CA_TIM_MAX] = { > + DVB_CA_ATTR_TIM(DVB_CA_TIM_WR_HIGH) > +, DVB_CA_ATTR_TIM(DVB_CA_TIM_WR_LOW) > +, DVB_CA_ATTR_TIM(DVB_CA_TIM_WR_DATA) > +}; > + > +static int dvb_ca_device_attrs_add(struct dvb_ca_private *ca) > +{ > + int i; > + > + for (i = 0; i < ARRAY_SIZE(dvb_ca_attrs); i++) > + if (device_create_file(ca->dvbdev->dev, &dvb_ca_attrs[i])) > + goto fail; > + return 0; > +fail: > + return -1; > +} > + > +static void ddb_device_attrs_del(struct dvb_ca_private *ca) > +{ > + int i; > + > + for (i = 0; i < ARRAY_SIZE(dvb_ca_attrs); i++) > + device_remove_file(ca->dvbdev->dev, &dvb_ca_attrs[i]); > +} > + > +/* ************************************************************************** */ > /* Initialisation/shutdown functions */ > > /** > @@ -1903,6 +2026,10 @@ int dvb_ca_en50221_init(struct dvb_adapter *dvb_adapter, > ret = -EINTR; > goto unregister_device; > } > + > + if (dvb_ca_device_attrs_add(ca)) > + goto unregister_device; > + > mb(); > > /* create a kthread for monitoring this CA device */ > @@ -1912,10 +2039,12 @@ int dvb_ca_en50221_init(struct dvb_adapter *dvb_adapter, > ret = PTR_ERR(ca->thread); > pr_err("dvb_ca_init: failed to start kernel_thread (%d)\n", > ret); > - goto unregister_device; > + goto delete_attrs; > } > return 0; > > +delete_attrs: > + ddb_device_attrs_del(ca); > unregister_device: > dvb_unregister_device(ca->dvbdev); > free_slot_info: > @@ -1946,6 +2075,7 @@ void dvb_ca_en50221_release(struct dvb_ca_en50221 *pubca) > for (i = 0; i < ca->slot_count; i++) > dvb_ca_en50221_slot_shutdown(ca, i); > > + ddb_device_attrs_del(ca); > dvb_remove_device(ca->dvbdev); > dvb_ca_private_put(ca); > pubca->private = NULL; >
