Subject: Re: [PATCH 2/4] staging: wilc1000: modified wilc_spi_read_int() by
 using GENMASK macro
To: Dan Carpenter <dan.carpenter@oracle.com>,
        Ajay Singh <ajay.kathat@microchip.com>
CC: <devel@driverdev.osuosl.org>, <venkateswara.kaja@microchip.com>,
        <gregkh@linuxfoundation.org>, <linux-wireless@vger.kernel.org>,
        <ganesh.krishna@microchip.com>, <adham.abozaeid@microchip.com>,
        <aditya.shankar@microchip.com>
References: <1519229532-11265-1-git-send-email-ajay.kathat@microchip.com>
 <1519229532-11265-3-git-send-email-ajay.kathat@microchip.com>
 <20180222073731.ambug44zxpmwm76w@mwanda>
 <8a20dcf4-8cfd-93bd-539e-e30e01f2a3b1@microchip.com>
From: Claudiu Beznea <Claudiu.Beznea@microchip.com>
Message-ID: <6326b112-c902-37ff-7692-b6cdab124d21@microchip.com> (sfid-20180222_102810_071595_3255349A)
Date: Thu, 22 Feb 2018 11:28:02 +0200
MIME-Version: 1.0
In-Reply-To: <8a20dcf4-8cfd-93bd-539e-e30e01f2a3b1@microchip.com>
Content-Type: text/plain; charset="utf-8"
Sender: linux-wireless-owner@vger.kernel.org


On 22.02.2018 11:23, Claudiu Beznea wrote:
> Hi Dan,
Sorry, I intended to be address this to Ajay,
> 
> On 22.02.2018 09:37, Dan Carpenter wrote:
>> On Wed, Feb 21, 2018 at 09:42:10PM +0530, Ajay Singh wrote:
>>> Use existing macro GENMASK to get the bitmask value. Moved the code to
>>> get the bitmask value outside the loop, as its only required one time.
>>>
>>> Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
>>> ---
>>>  drivers/staging/wilc1000/wilc_spi.c | 3 +--
>>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/staging/wilc1000/wilc_spi.c b/drivers/staging/wilc1000/wilc_spi.c
>>> index 131d2b7..c63f534 100644
>>> --- a/drivers/staging/wilc1000/wilc_spi.c
>>> +++ b/drivers/staging/wilc1000/wilc_spi.c
>>> @@ -955,6 +955,7 @@ static int wilc_spi_read_int(struct wilc *wilc, u32 *int_status)
>>>  	tmp = (byte_cnt >> 2) & IRQ_DMA_WD_CNT_MASK;
>>>  
>>>  	j = 0;
>>> +	unknown_mask = GENMASK(g_spi.nint - 1, 0);
>>>  	do {
>>>  		wilc_spi_read_reg(wilc, 0x1a90, &irq_flags);
>>>  		tmp |= ((irq_flags >> 27) << IRG_FLAGS_OFFSET);
>>> @@ -964,8 +965,6 @@ static int wilc_spi_read_int(struct wilc *wilc, u32 *int_status)
>>>  			tmp |= (((irq_flags >> 0) & 0x7) << k);
>>>  		}
>>>  
>>> -		unknown_mask = ~((1ul << g_spi.nint) - 1);
>>> -
>>
>> This isn't right at all...  Say g_spi.nint is zero, then we're doing
>> GENMASK(-1, 0) which seems like it should be undefined.  If g_spi.nint
>> is 1 then "GENMASK(1 - 1, 0)" is 0x1 but "~((1 < 1) - 1)" is ~0x1.
>>
> 
> Even in this driver g_spi.nint is always constant and equal with NUM_INT_EXT
> (which is 3), it seems that enabling interrupts before initializing g_spi.nint
> may lead to the state where g_spi.nint = 0, as Dan pointed.
> 
> int wilc1000_wlan_init(struct net_device *dev, struct wilc_vif *vif)
> {
> 		// ...
>                 if (wl->gpio >= 0 && init_irq(dev)) {
>                         ret = -EIO;
>                         goto _fail_locks_;
>                 }
> 
> 		// ...
>                 ret = linux_wlan_start_firmware(dev); -> calls
> linux_wlan_start_firmware which in turn calls wilc->hif_func->hif_sync_ext(wilc,
> NUM_INT_EXT);
> 
> 	
> }
> 
> Thank you,
> Claudiu Beznea
> 
>> I'm done reviewing this patch series...  You need to be more careful.
>> Create a small test program to test your patches.  As a reviewer,
>> creating test programs is how I review your patches.
>>
>> #include <sys/types.h>
>> #include <sys/stat.h>
>> #include <fcntl.h>
>> #include <stdio.h>
>> #include <stdlib.h>
>> #include <limits.h>
>> #include <string.h>
>> #include "/home/dcarpenter/progs/smatch/devel/check_debug.h"
>> #include "kernel.h"
>> #include <assert.h>
>> #include <fcntl.h>
>> #include <sys/time.h>
>> #include <sys/ioctl.h>
>> #include <linux/blktrace_api.h>
>> #include <linux/fs.h>
>>
>> #define BITS_PER_LONG 64
>> #define GENMASK(h, l) \
>>         (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>>
>> int main(void)
>> {
>>         int i;
>>         u32 mask1, mask2;
>>
>>         for (i = 0; i < 32; i++) {
>>                 mask1 = ~((1ul << i) - 1);
>>                 mask2 = GENMASK(i - 1, 0);
>>                 if (mask1 == mask2)
>>                         continue;
>>                 printf("ONE 0x%x %d\n", mask1, i);
>>                 printf("TWO 0x%x\n", mask2);
>>         }
>>         return 0;
>> }
>>
>> regards,
>> dan carpenter
>>
>>
>>
>> _______________________________________________
>> devel mailing list
>> devel@linuxdriverproject.org
>> http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
>>
>