Re: [PATCHv2 1/2] amba pl011: workaround for uart registers lockup
From: Greg KH
Date: Tue May 17 2011 - 14:24:12 EST
On Tue, May 17, 2011 at 10:50:17AM +0530, Shreshtha Kumar SAHU wrote:
> From: Shreshtha Kumar Sahu <shreshthakumar.sahu@xxxxxxxxxxxxxx>
> This workaround aims to break the deadlock situation
> which raises during continuous transfer of data for long
> duration over uart with hardware flow control. It is
> observed that CTS interrupt cannot be cleared in uart
> interrupt register (ICR). Hence further transfer over
> uart gets blocked.
> It is seen that during such deadlock condition ICR
> don't get cleared even on multiple write. This leads
> pass_counter to decrease and finally reach zero. This
> can be taken as trigger point to run this UART_BT_WA.
> Workaround backups the register configuration, does soft
> reset of UART using BIT-0 of PRCC_K_SOFTRST_SET/CLEAR
> registers and restores the registers.
> This patch also provides support for uart init and exit
> function calls if present.
Why? You don't use these callbacks in this driver, so why add them?
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