From: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> Some architecture like ARM assign masterIDs at the HW design phase. Those are therefore unreachable to users, making masterID management in the generic STM core irrelevant. In this kind of configuration channels are shared between masters rather than being allocated on a per master basis. This patch adds a new 'mshared' flag to struct stm_data that tells the core that this specific STM device doesn't need explicit masterID management. In the core sw_start/end of masterID are set to '1', i.e there is only one masterID to deal with. Also this patch depends on [1], so that the number of masterID is '1' too. Finally the lower and upper bound for masterIDs as presented in ($SYSFS)/class/stm/XYZ.stm/masters and ($SYSFS)/../stp-policy/XYZ.stm.my_policy/some_device/masters are set to '-1'. That way users can't confuse them with architecture where masterID management is required (where any other value would be valid). [1] https://lkml.org/lkml/2015/12/22/348 Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> Signed-off-by: Chunyan Zhang <zhang.chunyan@xxxxxxxxxx> --- drivers/hwtracing/stm/core.c | 18 ++++++++++++++++-- drivers/hwtracing/stm/policy.c | 18 ++++++++++++++++-- include/linux/stm.h | 8 ++++++++ 3 files changed, 40 insertions(+), 4 deletions(-) diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index b6445d9..7f71d54 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -44,9 +44,15 @@ static ssize_t masters_show(struct device *dev, char *buf) { struct stm_device *stm = to_stm_device(dev); - int ret; + int ret, sw_start, sw_end; + + sw_start = stm->data->sw_start; + sw_end = stm->data->sw_end; - ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end); + if (stm->data->mshared) + sw_start = sw_end = STM_SHARED_MASTERID; + + ret = sprintf(buf, "%d %d\n", sw_start, sw_end); return ret; } @@ -618,7 +624,15 @@ int stm_register_device(struct device *parent, struct stm_data *stm_data, if (!stm_data->packet || !stm_data->sw_nchannels) return -EINVAL; + /* + * MasterIDs are assigned at HW design phase. As such the core is + * using a single master for interaction with this device. + */ + if (stm_data->mshared) + stm_data->sw_start = stm_data->sw_end = 1; + nmasters = stm_data->sw_end - stm_data->sw_start; + stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL); if (!stm) return -ENOMEM; diff --git a/drivers/hwtracing/stm/policy.c b/drivers/hwtracing/stm/policy.c index 17a1416..19455db 100644 --- a/drivers/hwtracing/stm/policy.c +++ b/drivers/hwtracing/stm/policy.c @@ -80,10 +80,17 @@ static ssize_t stp_policy_node_masters_show(struct config_item *item, char *page) { struct stp_policy_node *policy_node = to_stp_policy_node(item); + struct stm_device *stm = policy_node->policy->stm; + int first_master, last_master; ssize_t count; - count = sprintf(page, "%u %u\n", policy_node->first_master, - policy_node->last_master); + first_master = policy_node->first_master; + last_master = policy_node->last_master; + + if (stm && stm->data->mshared) + first_master = last_master = STM_SHARED_MASTERID; + + count = sprintf(page, "%d %d\n", first_master, last_master); return count; } @@ -106,6 +113,13 @@ stp_policy_node_masters_store(struct config_item *item, const char *page, if (!stm) goto unlock; + /* + * masterIDs are allocated in HW, no point in trying to + * change their values. + */ + if (stm->data->mshared) + goto unlock; + /* must be within [sw_start..sw_end], which is an inclusive range */ if (first > INT_MAX || last > INT_MAX || first > last || first < stm->data->sw_start || diff --git a/include/linux/stm.h b/include/linux/stm.h index 9d0083d..6fac8b1 100644 --- a/include/linux/stm.h +++ b/include/linux/stm.h @@ -18,6 +18,11 @@ #include <linux/device.h> /** + * The masterIDs are set in hardware and can't be queried + */ +#define STM_SHARED_MASTERID -1 + +/** * enum stp_packet_type - STP packets that an STM driver sends */ enum stp_packet_type { @@ -46,6 +51,8 @@ struct stm_device; * struct stm_data - STM device description and callbacks * @name: device name * @stm: internal structure, only used by stm class code + * @mshared: true if masterIDs are assigned in HW. If so @sw_start + * and @sw_end are set to '1' by the core. * @sw_start: first STP master available to software * @sw_end: last STP master available to software * @sw_nchannels: number of STP channels per master @@ -71,6 +78,7 @@ struct stm_device; struct stm_data { const char *name; struct stm_device *stm; + bool mshared; unsigned int sw_start; unsigned int sw_end; unsigned int sw_nchannels; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
