[PATCH 30/40] sandbox: iommu: remove lmb allocation in the driver

[Sughosh Ganu]

On Fri, 26 Jul 2024 at 05:02, Simon Glass <sjg at chromium.org> wrote:
>
> Hi Sughosh,
>
> On Wed, 24 Jul 2024 at 00:05, Sughosh Ganu <sughosh.ganu at linaro.org> wrote:
> >
> > The sandbox iommu driver uses the LMB module to allocate a particular
> > range of memory for the device virtual address(DVA). This used to work
> > earlier since the LMB memory map was caller specific and not
> > global. But with the change to make the LMB allocations global and
> > persistent, adding this memory range has other side effects. On the
> > other hand, the sandbox iommu test expects to see this particular
> > value of the DVA. Use the DVA address directly, instead of mapping it
> > in the LMB memory map, and then have it allocated.
> >
> > Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> > ---
> > Changes since rfc: None
> >
> >  drivers/iommu/sandbox_iommu.c | 9 ++-------
> >  1 file changed, 2 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/iommu/sandbox_iommu.c b/drivers/iommu/sandbox_iommu.c
> > index 505f2c3250..15ecaacbb3 100644
> > --- a/drivers/iommu/sandbox_iommu.c
> > +++ b/drivers/iommu/sandbox_iommu.c
> > @@ -5,10 +5,10 @@
> >
> >  #include <dm.h>
> >  #include <iommu.h>
> > -#include <lmb.h>
> >  #include <asm/io.h>
> >  #include <linux/sizes.h>
> >
> > +#define DVA_ADDR               0x89abc000
>
> This is a very strange address. You can put this in
> arch/sandbox/include/asm/test.h and check it in the test. I suggest
> using something like 0x12345678 so it is obviously meaningless.

You will see that I am using the same address that is being used
currently. I did not want to make any changes to what is working, nor
did I want to spend time debugging if this logic can be improved --
that is not the purpose of this series.

>
> >  #define IOMMU_PAGE_SIZE                SZ_4K
> >
> >  static dma_addr_t sandbox_iommu_map(struct udevice *dev, void *addr,
> > @@ -20,8 +20,7 @@ static dma_addr_t sandbox_iommu_map(struct udevice *dev, void *addr,
> >         paddr = ALIGN_DOWN(virt_to_phys(addr), IOMMU_PAGE_SIZE);
> >         off = virt_to_phys(addr) - paddr;
> >         psize = ALIGN(size + off, IOMMU_PAGE_SIZE);
> > -
> > -       dva = lmb_alloc(psize, IOMMU_PAGE_SIZE, LMB_NONE);
> > +       dva = (phys_addr_t)DVA_ADDR;
> >
> >         return dva + off;
> >  }
> > @@ -35,8 +34,6 @@ static void sandbox_iommu_unmap(struct udevice *dev, dma_addr_t addr,
> >         dva = ALIGN_DOWN(addr, IOMMU_PAGE_SIZE);
> >         psize = size + (addr - dva);
> >         psize = ALIGN(psize, IOMMU_PAGE_SIZE);
> > -
> > -       lmb_free(dva, psize, LMB_NONE);
> >  }
> >
> >  static struct iommu_ops sandbox_iommu_ops = {
> > @@ -46,8 +43,6 @@ static struct iommu_ops sandbox_iommu_ops = {
> >
> >  static int sandbox_iommu_probe(struct udevice *dev)
> >  {
> > -       lmb_add(0x89abc000, SZ_16K, LMB_NONE);
> > -
> >         return 0;
> >  }
>
> If this function is empty, you should remove it.

Okay.

-sughosh

>
> >
> > --
> > 2.34.1
> >
>
> Regards,
> Simon