From: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
To: Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: spi/tegra114: add spi driver
Date: Mon, 4 Apr 2016 11:33:29 +0530 [thread overview]
Message-ID: <570203B1.3040304@nvidia.com> (raw)
In-Reply-To: <20160401135227.GA24190@mwanda>
On Friday 01 April 2016 07:22 PM, Dan Carpenter wrote:
> Hello Laxman Dewangan,
>
> The patch f333a331adfa: "spi/tegra114: add spi driver" from Feb 22,
> 2013, leads to the following static checker warning:
>
> drivers/spi/spi-tegra114.c:621 tegra_spi_init_dma_param()
> error: uninitialized variable 'dma_phys'.
>
> drivers/spi/spi-tegra114.c
> 583 dma_addr_t dma_phys;
> ^^^^^^^^^^^^^^^^^^^
> 584 int ret;
> 585 struct dma_slave_config dma_sconfig;
> 586
> 587 dma_chan = dma_request_slave_channel_reason(tspi->dev,
> 588 dma_to_memory ? "rx" : "tx");
> 589 if (IS_ERR(dma_chan)) {
> 590 ret = PTR_ERR(dma_chan);
> 591 if (ret != -EPROBE_DEFER)
> 592 dev_err(tspi->dev,
> 593 "Dma channel is not available: %d\n", ret);
> 594 return ret;
> 595 }
> 596
> 597 dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
> 598 &dma_phys, GFP_KERNEL);
>
> The issue is that in dma_alloc_attrs() if we can dma_alloc_from_coherent()
> then dma_phys is not set. I'm getting a couple similar errors and I'm
> not certian what to do about it.
>
The issue is with compiler actually.
we have code as
dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
&dma_phys, GFP_KERNEL);
if (!dma_buf) {
dev_err(tspi->dev, " Not able to allocate the dma
buffer\n");
dma_release_channel(dma_chan);
return -ENOMEM;
}
So if returned value "dma_buf" is not NULL then we can assume that
dma_phy is initialized other wise it should return NULL.
The static check is not able to find out that calling function has
initialized it or not.
--
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WARNING: multiple messages have this Message-ID (diff)
From: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
To: Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Cc: <linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
<linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: spi/tegra114: add spi driver
Date: Mon, 4 Apr 2016 11:33:29 +0530 [thread overview]
Message-ID: <570203B1.3040304@nvidia.com> (raw)
In-Reply-To: <20160401135227.GA24190@mwanda>
On Friday 01 April 2016 07:22 PM, Dan Carpenter wrote:
> Hello Laxman Dewangan,
>
> The patch f333a331adfa: "spi/tegra114: add spi driver" from Feb 22,
> 2013, leads to the following static checker warning:
>
> drivers/spi/spi-tegra114.c:621 tegra_spi_init_dma_param()
> error: uninitialized variable 'dma_phys'.
>
> drivers/spi/spi-tegra114.c
> 583 dma_addr_t dma_phys;
> ^^^^^^^^^^^^^^^^^^^
> 584 int ret;
> 585 struct dma_slave_config dma_sconfig;
> 586
> 587 dma_chan = dma_request_slave_channel_reason(tspi->dev,
> 588 dma_to_memory ? "rx" : "tx");
> 589 if (IS_ERR(dma_chan)) {
> 590 ret = PTR_ERR(dma_chan);
> 591 if (ret != -EPROBE_DEFER)
> 592 dev_err(tspi->dev,
> 593 "Dma channel is not available: %d\n", ret);
> 594 return ret;
> 595 }
> 596
> 597 dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
> 598 &dma_phys, GFP_KERNEL);
>
> The issue is that in dma_alloc_attrs() if we can dma_alloc_from_coherent()
> then dma_phys is not set. I'm getting a couple similar errors and I'm
> not certian what to do about it.
>
The issue is with compiler actually.
we have code as
dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
&dma_phys, GFP_KERNEL);
if (!dma_buf) {
dev_err(tspi->dev, " Not able to allocate the dma
buffer\n");
dma_release_channel(dma_chan);
return -ENOMEM;
}
So if returned value "dma_buf" is not NULL then we can assume that
dma_phy is initialized other wise it should return NULL.
The static check is not able to find out that calling function has
initialized it or not.
--
To unsubscribe from this list: send the line "unsubscribe linux-spi" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2016-04-04 6:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-01 13:52 spi/tegra114: add spi driver Dan Carpenter
2016-04-04 6:03 ` Laxman Dewangan [this message]
2016-04-04 6:03 ` Laxman Dewangan
[not found] ` <570203B1.3040304-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2016-04-04 8:56 ` Dan Carpenter
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