linux-kernel - Re: [PATCH V17 1/3] dmaengine: qcom_hidma: implement lower level hardware interface

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Date:	Tue, 26 Apr 2016 11:23:09 -0400
From:	Sinan Kaya <okaya@...eaurora.org>
To:	Andy Shevchenko <andy.shevchenko@...il.com>
Cc:	Vinod Koul <vinod.koul@...el.com>,
	dmaengine <dmaengine@...r.kernel.org>,
	Timur Tabi <timur@...eaurora.org>,
	devicetree <devicetree@...r.kernel.org>,
	Christopher Covington <cov@...eaurora.org>,
	Jon Masters <jcm@...hat.com>, shankerd@...eaurora.org,
	vikrams@...eaurora.org, Marc Zyngier <marc.zyngier@....com>,
	Mark Rutland <mark.rutland@....com>, eric.auger@...aro.org,
	Andy Gross <agross@...eaurora.org>,
	Arnd Bergmann <arnd@...db.de>, linux-arm-msm@...r.kernel.org,
	linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
	Dan Williams <dan.j.williams@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V17 1/3] dmaengine: qcom_hidma: implement lower level
 hardware interface

On 4/26/2016 11:10 AM, Andy Shevchenko wrote:
> On Tue, Apr 26, 2016 at 6:04 PM, Sinan Kaya <okaya@...eaurora.org> wrote:
>> On 4/25/2016 11:28 PM, Vinod Koul wrote:
>>> On Mon, Apr 11, 2016 at 10:21:11AM -0400, Sinan Kaya wrote:
> 
>>>> +    while (cause) {
>>>> +            if ((cause & BIT(HIDMA_IRQ_TR_CH_INVALID_TRE_BIT_POS)) ||
>>>> +                (cause & BIT(HIDMA_IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS)) ||
>>>> +                (cause & BIT(HIDMA_IRQ_EV_CH_WR_RESP_BIT_POS)) ||
>>>> +                (cause & BIT(HIDMA_IRQ_TR_CH_DATA_RD_ER_BIT_POS)) ||
>>>> +                (cause & BIT(HIDMA_IRQ_TR_CH_DATA_WR_ER_BIT_POS))) {
>>>
>>> Switch please
>>
>> Cause is a combined status register. Let's say it contains 0x41. I need to check
>> if bit 0 or bit 6 is set in this value for each case condition. The value is not 0x40
>> or 0x1.
>>
>> I created macro like this instead.
>>
>> +#define HIDMA_IS_ERR_INTERRUPT(cause)                          \
>> +       (cause & BIT(HIDMA_IRQ_TR_CH_INVALID_TRE_BIT_POS))   || \
>> +       (cause & BIT(HIDMA_IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS)) || \
>> +       (cause & BIT(HIDMA_IRQ_EV_CH_WR_RESP_BIT_POS))       || \
>> +       (cause & BIT(HIDMA_IRQ_TR_CH_DATA_RD_ER_BIT_POS))    || \
>> +       (cause & BIT(HIDMA_IRQ_TR_CH_DATA_WR_ER_BIT_POS))
> 
> This looks overheaded.
> 
> #define HIDMA_XXX (BIT(a) | BIT (b) ... BIT(n))
> 
>>
>> and replaced the if statement as follows
>>
>> if (HIDMA_IS_ERR_INTERRUPT(cause)) {
> 
> if (cause & HIDMA_XXX) {
> 

This is even better.

-- 
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project