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From: Gilles C. <gil...@xe...> - 2010-10-07 09:27:48
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Jan Kiszka wrote: > Am 07.10.2010 11:13, Gilles Chanteperdrix wrote: >> Jan Kiszka wrote: >>> Am 04.10.2010 22:13, Edward Hoffman wrote: >>>> I am attempting to port the Broadcom tg3 NetXtreme linux driver to >>>> rtnet. >>> Your port will be welcome! >>> >>>> The Broadcom driver internally utilizes >>>> spin_lock_bh/spin_unlock_bh to disable/enable software interrupts. >>>> There is no rtdm lock equivalent. >>>> I believe that software interrupts are used by the driver for the >>>> following reasons: >>>> 1. To allow for simultaneous DMA read write operations >>>> 2. To use shared local variables in a critical section of the driver. >>>> 3. To receive changes to settings variables in realtime from the >>>> userpace Nextreme utilities. (not sure about this one). >>>> >>>> What RTDM lock functions should I use to substitute for >>>> spin_lock_bh/spin_unlock_bh? Should I substitute >>>> rtdm_lock_get_irqsave/rtdm_lock_put_irqrestore? Or does rtdm need to ne >>>> extended for softirqs used internally by the driver? >>>> >>>> I looked through the other device drivers and could not detect the >>>> correct substitute. >>> As RTDM provides no abstraction of bottom-halves, there are also no >>> specific locking services to disable them. You have to use IRQ-disabling >>> services unless you are in IRQ context. >> Maybe if you want to only exclude the driver's irq, you may only disable >> the irq line at IC level, with rtdm_irq_disable? > > Usually discouraged due to potentially slow line-disabling services and > the breakage this will cause when the line is shared. Why would this cause breakage when the line is shared? -- Gilles. |
