linux-kernel - Re: [PATCH] remoteproc: qcom: Use of_reserved_mem

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Message-ID: <ZInY_9QjJXIo7Bn8@gerhold.net>
Date:   Wed, 14 Jun 2023 17:13:03 +0200
From:   Stephan Gerhold <stephan@...hold.net>
To:     Bjorn Andersson <andersson@...nel.org>
Cc:     Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] remoteproc: qcom: Use of_reserved_mem_lookup()

On Wed, Jun 14, 2023 at 08:12:13AM -0700, Bjorn Andersson wrote:
> On Wed, May 31, 2023 at 11:34:54AM +0200, Stephan Gerhold wrote:
> > Reserved memory can be either looked up using the generic function
> > of_address_to_resource() or using the special of_reserved_mem_lookup().
> > The latter has the advantage that it ensures that the referenced memory
> > region was really reserved and is not e.g. status = "disabled".
> > 
> > of_reserved_mem also supports allocating reserved memory dynamically at
> > boot time. This works only when using of_reserved_mem_lookup() since
> > there won't be a fixed address in the device tree.
> > 
> > Switch the code to use of_reserved_mem_lookup(), similar to
> > qcom_q6v5_wcss.c which is using it already. There is no functional
> > difference for static reserved memory allocations.
> > 
> > While at it this also adds two missing of_node_put() calls in
> > qcom_q6v5_pas.c.
> > 
> > Signed-off-by: Stephan Gerhold <stephan@...hold.net>
> > ---
> > See e.g. [1] for an example of dynamically allocated reserved memory.
> > (This patch does *not* depend on [1] and is useful without as well...)
> > 
> > NOTE: Changes in qcom_q6v5_adsp.c and qcom_q6v5_pas.c are untested,
> > I only checked qcom_q6v5_mss.c and qcom_wcnss.c on MSM8916/DB410c.
> > The code changes are pretty similar for all of those though.
> > 
> > [1]: https://lore.kernel.org/linux-arm-msm/20230510-dt-resv-bottom-up-v1-5-3bf68873dbed@gerhold.net/
> > ---
> >  drivers/remoteproc/qcom_q6v5_adsp.c | 22 ++++++++--------
> >  drivers/remoteproc/qcom_q6v5_mss.c  | 35 +++++++++++++++----------
> >  drivers/remoteproc/qcom_q6v5_pas.c  | 51 ++++++++++++++++++++-----------------
> >  drivers/remoteproc/qcom_wcnss.c     | 24 ++++++++---------
> >  4 files changed, 69 insertions(+), 63 deletions(-)
> > 
> > diff --git a/drivers/remoteproc/qcom_q6v5_adsp.c b/drivers/remoteproc/qcom_q6v5_adsp.c
> > index 6777a3bd6226..948b3d00a564 100644
> > --- a/drivers/remoteproc/qcom_q6v5_adsp.c
> > +++ b/drivers/remoteproc/qcom_q6v5_adsp.c
> > @@ -14,8 +14,8 @@
> >  #include <linux/kernel.h>
> >  #include <linux/mfd/syscon.h>
> >  #include <linux/module.h>
> > -#include <linux/of_address.h>
> >  #include <linux/of_device.h>
> > +#include <linux/of_reserved_mem.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/pm_domain.h>
> >  #include <linux/pm_runtime.h>
> > @@ -637,28 +637,26 @@ static int adsp_init_mmio(struct qcom_adsp *adsp,
> >  
> >  static int adsp_alloc_memory_region(struct qcom_adsp *adsp)
> >  {
> > +	struct reserved_mem *rmem = NULL;
> >  	struct device_node *node;
> > -	struct resource r;
> > -	int ret;
> >  
> >  	node = of_parse_phandle(adsp->dev->of_node, "memory-region", 0);
> > +	if (node)
> > +		rmem = of_reserved_mem_lookup(node);
> > +	of_node_put(node);
> > +
> >  	if (!node) {
> > -		dev_err(adsp->dev, "no memory-region specified\n");
> > +		dev_err(adsp->dev, "unable to resolve memory-region\n");
> >  		return -EINVAL;
> >  	}
> >  
> > -	ret = of_address_to_resource(node, 0, &r);
> > -	of_node_put(node);
> > -	if (ret)
> > -		return ret;
> > -
> > -	adsp->mem_phys = adsp->mem_reloc = r.start;
> > -	adsp->mem_size = resource_size(&r);
> 
> Aren't you missing a check for !rmem here? (The others has it)
> 

Indeed, thanks for spotting this! Will send a v2.

Stephan