I'm trying to do a simple STANDALONE application for Zynq. I want to use the 'time.h' to manipulate date/time. I know that there is no hardware implementation on a stanalone BSP, but I want to wire it up on my own.
During compilation, when I call 'time(NULL)' I get a error, that there is no implementation of '_gettimeofday()'. I've found it in and implemented it according to the function definition, so that the errors disappear and everything looks ok, but when I run my project on hardware, I see only zeroes from time().
Can anybody help?
Regards,
G2
Ok, I've done some research, and found this link. This is almost what I'v been searching, but instead of '_times()' I needed '_gettimeofday()' and this is my implementation:
int _gettimeofday(struct timeval *__p, void *__tz)
{
__p->tv_sec = (systemUsCounter / 1000000);
__p->tv_usec = systemUsCounter;
return 0;
}
I left the '__tz' pointer with no chainges.
So this is basicly how to utilize 'time.h' in a standalone application on Zynq.
Related
Good day,
I am currently writing my first boot-loader for the linux operating system for the cortex a72 processor using qemu.
Since I am doing some complex calculations (CRC32, SHA256, signature check...) the code takes quite some time to execute on one core. So I have decided to use the power of more than 1 core, to speed up computation, and have some parallelism.
From the research that I have conducted I found that I have to start up my second core using the PSCI protocole, and taking a look at the Device tree revealed the configuration of my psci. Here is some relevant information from the .dtb:
psci {
migrate = <0xc4000005>;
cpu_on = <0xc4000003>;
cpu_off = <0x84000002>;
cpu_suspend = <0xc4000001>;
method = "hvc";
compatible = "arm,psci-1.0", "arm,psci-0.2", "arm,psci";
};
cpu#0 {
phandle = <0x00008004>;
reg = <0x00000000>;
enable-method = "psci";
compatible = "arm,cortex-a72";
device_type = "cpu";
};
cpu#1 {
phandle = <0x00008003>;
reg = <0x00000001>;
enable-method = "psci";
compatible = "arm,cortex-a72";
device_type = "cpu";
};
So now it seems like there is all the needed information to start the second core.
However I am not sure how to use the hvc method to do that having found examples that only explain the smc method.
Furthermore, how should I implement concurrency and parallelism?
The basic usage I would wish to achieve is to have my CRC32 algorithm running on one core, and my SHA256 running on the other. Would the two cores be able to access the common UART? I guess that there is some way to know that a core has finished executing a program, so race conditions should not be hard to catch.
It would be of great help if anyone could provide any guidance to implement this feature.
Thanks in advance!
The official documentation of how to use PSCI calls is in the Arm Power State Coordination Interface Platform Design Document. But the short answer is that the only difference between the HVC method and the SMC method is that for one you use the "HVC" instruction and for the other the "SMC" instruction -- everything else is identical.
Recently I started to develop a bluetooth app using API exposed via D-BUS. After some research, I chose to use sd-bus library to communicate with D-Bus.
Here is my code:
#include <systemd/sd-bus.h>
sd_bus* bus_;
if (sd_bus_open_system(&bus_) < 0)
{
throw std::runtime_error("sd_bus_open_system");
}
sd_bus_error sd_error;
bool powered = true;
if (sd_bus_set_property(bus_,
"org.bluez",
"/org/bluez/hci0",
"org.bluez.Adapter1",
"Powered",
&sd_error,
"b", &powered) < 0)
{
throw std::runtime_error("Bluetooth Power On");
}
The code above throws "Bluetooth Power On" and the return value of sd_bus_set_property is -22 (EINVAL). I couldn't make much sense from sd_error, but for to whom may be interested, here is the details:
name:0x7fffffffdce8 "И\277UUU"
message:0x5555555d6fbd <handler::handler(std::span<door, 18446744073709551615ul>)+191> "\220H\213E\350dH+\004%("
_need_free:1439044320
I have checked the literal strings using D-Feet app and everything seems to be right.
I've tried running as root or without root.
I've tried adding the user to bluetooth group.
What is wrong with this code?
source code of sd_bus_set_property shows that internally, it calls "Set" from "org.freedesktop.DBus.Properties". Most of the bluetooth examples I've seen, do this without using "sd_bus_set_property", but I'm curious to see how it can be done via "sd_bus_set_property".
Thanks for reading.
I built systemd from source and stepped into its functions and saw at some point it checks the error and since it's not null, returns.
sd_bus_error sd_error = SD_BUS_ERROR_NULL;
fixed the issue.
I'm using the STM BlueNRG-MS chip on my peripheral device and after connection I'd like to read the name of the connected central device (android phone).
I thought I can do this directly in my user_notify routine which is registered as hci callback
/* Initialize the Host-Controller Interface */
hci_init(user_notify, NULL);
So on the EVT_LE_CONN_COMPLETE event, I take the provided handle for the central device and I use aci_gatt_read_using_charac_uuid() to read what I thought is the characteristic with the device name (uuid 0x2a00).
case EVT_LE_META_EVENT:
{
evt_le_meta_event *evt = (void *)event_pckt->data;
switch(evt->subevent){
case EVT_LE_CONN_COMPLETE:
{
evt_le_connection_complete *cc = (void *)evt->data;
GAP_ConnectionComplete_CB(cc->peer_bdaddr, cc->handle);
uint16_t uuid = 0x2a00;
resp = aci_gatt_read_using_charac_uuid(cc->handle, 0, 1, UUID_TYPE_16, (uint8_t*)&uuid);
LOG("GATT read status: %d", resp);
enqueEvent(EVENT_BLE_CONNECTED);
}
break;
}
}
Long story short, it doesn't work. First thing I'm not sure about is, what is the start_handle and end_handle parameter of aci_gatt_read_using_charac_uuid(), it returns ERR_INVALID_HCI_CMD_PARAMS.
Can someone shed some light here?
update
What also puzzles me is that the function aci_gatt_read_using_charac_uuid() is nowehere referenced in the BlueNRG-MS Programming Guidelines.
update2
I changed the function call to aci_gatt_read_using_charac_uuid(cc->handle, 0x0001, 0xffff, UUID_TYPE_16, (uint8_t*)&uuid); but I still get the ERR_INVALID_HCI_CMD_PARAMS. What which paramter could even be invalid? The uuid exists, I can read the device name if I use the BlueNRG GUI with a bluetooth dongle.
update3
Has anyone ever used this function or somehow managed to read a characteristic from a central device? I'd highly appreciate any help or hint.
Here you go, The BlueNRG-MS Bluetooth® LE stack application command interface (ACI) - User manual
page 75 - 4.6.25 Aci_Gatt_Read_Charac_Using_UUID()
and make sure you have called Aci_Gatt_Init()
The user manual is last revised July 2019, the document you link to is from 2018, don't know if this is why ?
The start_handle and end_handle is the range of handles in your service as pictured here -
Here is a discussion to the closest thing I could find to match your question.
As it turned out there are two bugs in the BlueNRG API.
In bluenrg_aci_const.h file the OCF code OCF_GATT_READ_USING_CHARAC_UUID shall be 0x119 instead of 0x109.
And in the implementation of the aci_gatt_read_using_charac_uuid() function, there is a missing setting on event:
rq.event = EVT_CMD_STATUS;
Patching them fixed the issue.
I'd like to let my kernel module periodically do something (a certain time interval, like 10 sec) in FreeBSD kernel. Any example for doing that?
I searched and found that there are functions like callout/timeout(old), but they seem complicated, and I cannot find good examples for them. For callout'', it seems thatcallout_reset'' is similar to the function I want (arguments include a handler and a time interval). But it seems to only execute once. So I'm confused.
Examples are the best, even for function ``timeout''.
You need to use callout(9). As for examples... Hm, for a real-world code you could take a look at this: http://svnweb.freebsd.org/base/head/sys/dev/iscsi/iscsi.c?revision=275925&view=markup; search for is_callout. Basically, you need 'struct timeout', a function that will get called periodically, and then you need to get the timer ticking:
struct callout callout;
static void
callout_handler(void *whatever)
{
// do your stuff, and make sure to get called again after 'seconds'.
callout_schedule(&callout, seconds * hz);
}
static void
start_ticking(void)
{
callout_init(&callout, 1);
callout_reset(&callout, seconds * hz, callout_handler, whatever);
}
So creating a Windows service using Visual Studio is fairly trivial. My question goes a bit deeper as to what actually makes an executable installable as a service & how to write a service as a straight C application. I couldn't find a lot of references on this, but I'm presuming there has to be some interface I can implement so my .exe can be installed as a service.
Setting up your executable as a service is part of it, but realistically it's usually handled by whatever installation software you're using. You can use the command line SC tool while testing (or if you don't need an installer).
The important thing is that your program has to call StartServiceCtrlDispatcher() upon startup. This connects your service to the service control manager and sets up a ServiceMain routine which is your services main entry point.
ServiceMain (you can call it whatever you like actually, but it always seems to be ServiceMain) should then call RegisterServiceCtrlHandlerEx() to define a callback routine so that the OS can notify your service when certain events occur.
Here are some snippets from a service I wrote a few years ago:
set up as service:
SERVICE_TABLE_ENTRY ServiceStartTable[] =
{
{ "ServiceName", ServiceMain },
{ 0, 0 }
};
if (!StartServiceCtrlDispatcher(ServiceStartTable))
{
DWORD err = GetLastError();
if (err == ERROR_FAILED_SERVICE_CONTROLLER_CONNECT)
return false;
}
ServiceMain:
void WINAPI ServiceMain(DWORD, LPTSTR*)
{
hServiceStatus = RegisterServiceCtrlHandlerEx("ServiceName", ServiceHandlerProc, 0);
service handler:
DWORD WINAPI ServiceHandlerProc(DWORD ControlCode, DWORD, void*, void*)
{
switch (ControlCode)
{
case SERVICE_CONTROL_INTERROGATE :
// update OS about our status
case SERVICE_CONTROL_STOP :
// shut down service
}
return 0;
}
Hope this helps:
http://support.microsoft.com/kb/251192
It would seem that you simple need to run this exe against a binary executable to register it as a service.
Basically there are some registry settings you have to set as well as some interfaces to implement.
Check out this: http://msdn.microsoft.com/en-us/library/ms685141.aspx
You are interested in the SCM (Service Control Manager).
I know I'm a bit late to the party, but I've recently had this same question, and had to struggle through the interwebs looking for answers.
I managed to find this article in MSDN that does in fact lay the groundwork. I ended up combining many of the files here into a single exe that contains all of the commands I need, and added in my own "void run()" method that loops for the entirely life of the service for my own needs.
This would be a great start to someone else with exactly this question, so for future searchers out there, check it out:
The Complete Service Sample
http://msdn.microsoft.com/en-us/library/bb540476(VS.85).aspx