linux-kernel - Re: [PATCH v3 07/15] firmware: qcom: scm: make qcom_scm_assign

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Message-ID: <CAMRc=MdO3ctA-g=VVhXp9QKPdUT1XX0iEKTzEKzHjNzh_=-jPQ@mail.gmail.com>
Date:   Wed, 11 Oct 2023 16:33:53 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Andrew Halaney <ahalaney@...hat.com>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Elliot Berman <quic_eberman@...cinc.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Guru Das Srinagesh <quic_gurus@...cinc.com>,
        Maximilian Luz <luzmaximilian@...il.com>,
        Alex Elder <elder@...aro.org>,
        Srini Kandagatla <srinivas.kandagatla@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, kernel@...cinc.com,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH v3 07/15] firmware: qcom: scm: make qcom_scm_assign_mem()
 use the TZ allocator

On Wed, Oct 11, 2023 at 3:54 PM Andrew Halaney <ahalaney@...hat.com> wrote:
>
> On Wed, Oct 11, 2023 at 09:41:49AM +0200, Bartosz Golaszewski wrote:
> > On Wed, Oct 11, 2023 at 12:19 AM Andrew Halaney <ahalaney@...hat.com> wrote:
> > >
> > > On Mon, Oct 09, 2023 at 05:34:19PM +0200, Bartosz Golaszewski wrote:
> > > > From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> > > >
> > > > Let's use the new TZ memory allocator to obtain a buffer for this call
> > > > instead of using dma_alloc_coherent().
> > > >
> > > > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> > > > ---
> > > >  drivers/firmware/qcom/qcom_scm.c | 10 ++++++----
> > > >  1 file changed, 6 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
> > > > index 71e98b666391..754f6056b99f 100644
> > > > --- a/drivers/firmware/qcom/qcom_scm.c
> > > > +++ b/drivers/firmware/qcom/qcom_scm.c
> > > > @@ -4,6 +4,7 @@
> > > >   */
> > > >
> > > >  #include <linux/arm-smccc.h>
> > > > +#include <linux/cleanup.h>
> > > >  #include <linux/clk.h>
> > > >  #include <linux/completion.h>
> > > >  #include <linux/cpumask.h>
> > > > @@ -998,14 +999,13 @@ int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
> > > >       struct qcom_scm_mem_map_info *mem_to_map;
> > > >       phys_addr_t mem_to_map_phys;
> > > >       phys_addr_t dest_phys;
> > > > -     dma_addr_t ptr_phys;
> > > > +     phys_addr_t ptr_phys;
> > > >       size_t mem_to_map_sz;
> > > >       size_t dest_sz;
> > > >       size_t src_sz;
> > > >       size_t ptr_sz;
> > > >       int next_vm;
> > > >       __le32 *src;
> > > > -     void *ptr;
> > >
> > > nit: couldn't you keep this up here?
> > >
> >
> > This still needs to make its way into the coding style guide but I got
> > yelled at by Linus Torvalds personally for not declaring the managed
> > variables where they are initialized. So this is the correct approach.
>
> I'm being a stick in the mud, but couldn't you initialize to NULL and
> keep them all up top? That seems more in line with the current "declare
> all variables at the start of function" guideline the kernel follows.
>
> Not a big deal... yours call! but /me shrugs
>

I agree with you but it's not my call to make. Please see[1].

Bartosz

[1] https://lore.kernel.org/lkml/20230919193516.GA20937@noisy.programming.kicks-ass.net/T/#m7f97e10dbfde777f58493398a77933e6a2f3c15d

> >
> > Bart
> >
> > > Otherwise,
> > >
> > > Reviewed-by: Andrew Halaney <ahalaney@...hat.com>
> > >
> > > >       int ret, i, b;
> > > >       u64 srcvm_bits = *srcvm;
> > > >
> > > > @@ -1015,10 +1015,13 @@ int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
> > > >       ptr_sz = ALIGN(src_sz, SZ_64) + ALIGN(mem_to_map_sz, SZ_64) +
> > > >                       ALIGN(dest_sz, SZ_64);
> > > >
> > > > -     ptr = dma_alloc_coherent(__scm->dev, ptr_sz, &ptr_phys, GFP_KERNEL);
> > > > +     void *ptr __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
> > > > +                                                     ptr_sz, GFP_KERNEL);
> > > >       if (!ptr)
> > > >               return -ENOMEM;
> > > >
> > > > +     ptr_phys = qcom_tzmem_to_phys(ptr);
> > > > +
> > > >       /* Fill source vmid detail */
> > > >       src = ptr;
> > > >       i = 0;
> > > > @@ -1047,7 +1050,6 @@ int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
> > > >
> > > >       ret = __qcom_scm_assign_mem(__scm->dev, mem_to_map_phys, mem_to_map_sz,
> > > >                                   ptr_phys, src_sz, dest_phys, dest_sz);
> > > > -     dma_free_coherent(__scm->dev, ptr_sz, ptr, ptr_phys);
> > > >       if (ret) {
> > > >               dev_err(__scm->dev,
> > > >                       "Assign memory protection call failed %d\n", ret);
> > > > --
> > > > 2.39.2
> > > >
> > >
> >
>