Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

RE: Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

goldwake — Sun, 30 Jun 2019 22:44:28 GMT

This issue is a pain for me as well. Having central and peripheral connections doesn't work very well with the link ctx mgr. It's a bit wasteful having sizeof(ble_nus_client_context_t) * num_central_connections unused bytes allocated for the ctx manager. Especially when you've got a lot of connection which use up a lot ofRAM already.

I know it's not ideal but I use my own blcm_link_ctx_get function to handle this

static uint32_t get_link_ctx(ble_gm_device_t * p_gm_device, uint16_t conn_handle, ble_gm_device_client_context_t ** const p_client)
{
    if (p_client == NULL)
    {
        return NRF_ERROR_NULL;
    }
    else
    {
        *p_client = NULL;
    }
    
    VERIFY_PARAM_NOT_NULL(p_gm_device->p_link_ctx_storage);
    VERIFY_PARAM_NOT_NULL(p_gm_device->p_link_ctx_storage->p_ctx_data_pool);
    VERIFY_TRUE((p_gm_device->p_link_ctx_storage->link_ctx_size % BYTES_PER_WORD) == 0, NRF_ERROR_INVALID_PARAM);
    
    uint16_t link_ctx_index = 0;
    for(link_ctx_index = 0; link_ctx_index < p_gm_device->p_link_ctx_storage->max_links_cnt; link_ctx_index++)
    {
        if(p_gm_device->conn_handles[link_ctx_index] == conn_handle )
        {
            *p_client = (void *) ((uint8_t *) p_gm_device->p_link_ctx_storage->p_ctx_data_pool + 
                             link_ctx_index * p_gm_device->p_link_ctx_storage->link_ctx_size);
            return NRF_SUCCESS;
        }
    }
    return NRF_ERROR_NOT_FOUND;
    
}

RE: Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

Vidar Berg — Tue, 19 Mar 2019 13:40:37 GMT

With the current implementation, the more correct way would probably be to use the link context manager for all links and not just the NUS connection. But I think it's ok to modify the SDK module as you did.

RE: Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

Andrea Aizza — Mon, 18 Mar 2019 15:08:12 GMT

Yes, sure. The below is sufficient. But I did not wanna modify SDK files. Just wondering what is the right way to do it.

diff --git a/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c b/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c
index 2a139f4..11ae062 100644
--- a/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c
+++ b/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c
@@ -67,10 +67,10 @@ ret_code_t blcm_link_ctx_get(blcm_link_ctx_storage_t const * const p_link_ctx_st
         return NRF_ERROR_NOT_FOUND;
     }
 
-    if (conn_id >= p_link_ctx_storage->max_links_cnt)
-    {
-        return NRF_ERROR_NO_MEM;
-    }
+    //if (conn_id >= p_link_ctx_storage->max_links_cnt)^M
+    //{^M
+    //    return NRF_ERROR_NO_MEM;^M
+    //}^M
 
     *pp_ctx_data = (void *) ((uint8_t *) p_link_ctx_storage->p_ctx_data_pool + 
                              conn_id * p_link_ctx_storage->link_ctx_size);

RE: Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

Vidar Berg — Mon, 18 Mar 2019 10:36:32 GMT

Hi,

Sorry, you're right, the link context manager uses the connection handle value to determine if it has enough buffer for the connection even though it's only used for the NUS connection in this case. Does it work if you also comment out the error check in ble_link_ctx_manager?

RE: Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

Andrea Aizza — Fri, 15 Mar 2019 13:30:46 GMT

Hi,

does not work. conn_id==8 still reaches components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c as above and generates same error above.

(gdb) p conn_handle
$2 = 8
(gdb) s
nrf_atflags_get (p_flags=p_flags@entry=0x2000bf90 <m_bcs+4>, flag_index=flag_index@entry=8)
    at ../../../../../../components/libraries/atomic_flags/nrf_atflags.c:95
95          return (p_flags[FLAG_BASE(flag_index)] & FLAG_MASK(flag_index)) != 0;
(gdb) s
blcm_link_ctx_get (p_link_ctx_storage=0x2000ad74 <m_nus_link_ctx_storage>,
    conn_handle=conn_handle@entry=8, pp_ctx_data=pp_ctx_data@entry=0x2000fba4)
    at ../../../../../../components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c:65
65          if (conn_id == BLE_CONN_STATE_MAX_CONNECTIONS)
(gdb) bt
#0  blcm_link_ctx_get (p_link_ctx_storage=0x2000ad74 <m_nus_link_ctx_storage>, conn_handle=conn_handle@entry=8, pp_ctx_data=pp_ctx_data@entry=0x2000fba4)
    at ../../../../../../components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c:65
#1  0x000342d8 in ble_nus_data_send (p_nus=p_nus@entry=0x2000ad58 <m_nus>, p_data=p_data@entry=0x2000b83c <data_array> "<removed text>\r", p_length=0x2000fbd2, 
    p_length@entry=0x2000fbb2, conn_handle=<optimized out>) at ../../../../../../components/ble/ble_services/ble_nus/ble_nus.c:325
#2  0x0002c268 in send_to_nus (fmt=0x35a38 "blished, starting DB discovery.") at ../../../main.c:185
#3  0x0002c69e in ble_evt_handler (p_ble_evt=0x2000fc84, p_context=<optimized out>) at ../../../main.c:433
#4  0x0002d0aa in nrf_sdh_ble_evts_poll (p_context=<optimized out>) at ../../../../../../components/softdevice/common/nrf_sdh_ble.c:307
#5  0x0002d056 in nrf_sdh_evts_poll () at ../../../../../../components/softdevice/common/nrf_sdh.c:358
#6  SWI2_EGU2_IRQHandler () at ../../../../../../components/softdevice/common/nrf_sdh.c:367
#7  <signal handler called>
#8  0x00015c7e in ?? ()
#9  0x00015c7c in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Anything I am doing wrong?

RE: Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

Vidar Berg — Fri, 15 Mar 2019 09:16:30 GMT

Hi Andrea,

Yes, that's what I meant. My proposed change should prevent the "BLE_HRS_C" connections from being processed by the NUS service.

RE: Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

Andrea Aizza — Thu, 14 Mar 2019 17:16:38 GMT

Hi,

ok, thanks and noted about not available sample.

Do you mean that i need anyhow to modify ble_nus.c? And you modification is the one to take, not the one I actually made (see below)?

diff --git a/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c b/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c
index 2a139f4..11ae062 100644
--- a/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c
+++ b/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c
@@ -67,10 +67,10 @@ ret_code_t blcm_link_ctx_get(blcm_link_ctx_storage_t const * const p_link_ctx_st
         return NRF_ERROR_NOT_FOUND;
     }
 
-    if (conn_id >= p_link_ctx_storage->max_links_cnt)
-    {
-        return NRF_ERROR_NO_MEM;
-    }
+    //if (conn_id >= p_link_ctx_storage->max_links_cnt)^M
+    //{^M
+    //    return NRF_ERROR_NO_MEM;^M
+    //}^M
 
     *pp_ctx_data = (void *) ((uint8_t *) p_link_ctx_storage->p_ctx_data_pool + 
                              conn_id * p_link_ctx_storage->link_ctx_size);

Regards,

Andrea

RE: Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

Vidar Berg — Thu, 14 Mar 2019 12:42:41 GMT

Hi,

We don't have an example for combining hrs_c and nus unfortunately. But you can try adding filtering of the BLE events in the NUS services so only connections with GAP peripheral role will be processed by the event handler.

You can use the connection state module to keep track GAP roles for each active connections. E.g.,

diff --git a/components/ble/ble_services/ble_nus/ble_nus.c b/components/ble/ble_services/ble_nus/ble_nus.c
index 1c32b52..631f1c4 100644
--- a/components/ble/ble_services/ble_nus/ble_nus.c
+++ b/components/ble/ble_services/ble_nus/ble_nus.c
@@ -217,7 +217,8 @@ static void on_hvx_tx_complete(ble_nus_t * p_nus, ble_evt_t const * p_ble_evt)

 void ble_nus_on_ble_evt(ble_evt_t const * p_ble_evt, void * p_context)
 {
-    if ((p_context == NULL) || (p_ble_evt == NULL))
+    if ((p_context == NULL) || (p_ble_evt == NULL) ||
+        (BLE_GAP_ROLE_PERIPH != ble_conn_state_role(p_ble_evt->evt.common_evt.conn_handle)))
     {
         return;
     }