On Sat, Feb 1, 2014 at 12:32 AM, m silverstri <michael.j.silverstri@xxxxxxxxx> wrote: don't top-post > In my driver code, > I want to set a bit in a HW Register 1. HW will send an interrupt Yes this is how most drivers work. > when setting the register is done. > I don't want my driver code to block until the interrupt is sent from the HW. so i suppose this is what you want to do. write ->register->interrupt happens->disable register ->handle interrupt --->enable register. Look at any driver code from linux kernel code and it mostly does this. > > > > On Sat, Feb 1, 2014 at 12:06 AM, anish singh > <anish198519851985@xxxxxxxxx> wrote: >> On Fri, Jan 31, 2014 at 11:55 PM, m silverstri >> <michael.j.silverstri@xxxxxxxxx> wrote: >>> Hi, >>> >>> I read this article http://www.linuxjournal.com/article/5833 to learn >>> about spinlock. I try this to use it in my kernel driver. >>> >>> Here is what my driver code needs to do: >>> In f1(), it will get the spin lock, and caller can call f2() will wait >>> for the lock since the spin lock is not being unlock. The spin lock >>> will be unlock in my interrupt handler (triggered by the HW). >> Wrong design!!! >>> >>> void f1() { >>> spin_lock(&mylock); >>> // write hardware >>> REG_ADDR += FLAG_A; >> So here you take spinlock and release in interrupt handler.What >> if there is no interrupt handler and someone calls this fucntion >> he will blocked forever. >>> >>> } >>> >>> void f2() { >>> spin_lock(&mylock); >>> //... >>> } >>> >>> The hardware will send the application an interrupt and my interrupt >>> handler will call spin_unlock(&mylock); >>> >>> My question is if I call >>> f1() >>> f2() // i want this to block until the interrupt return saying settingyou >>> REG_ADDR is done. >>> >>> when I run this, I get an exception in kernel saying a deadlock " >>> INFO: possible recursive locking detected" >>> >>> How can I re-write my code so that kernel does not think I have a deadlock? >>> >>> I want my driver code to wait until HW sends me an interrupt saying >>> setting REG_ADDR is done. >> Let us know what is your requirement?I am sure there must be a simple >> way to handle than this magic done here. >> Explain what are you trying to do in detail and I am sure lot of >> people will jump >> to help. >>> >>> Thank you. >>> >>> _______________________________________________ >>> Kernelnewbies mailing list >>> Kernelnewbies@xxxxxxxxxxxxxxxxx >>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
