[U-Boot] [PATCH 4/6] fdtdec: Implement fdtdec_add_reserved_memory()

[Thierry Reding <thierry.reding@gmail.com>]

On Sun, Mar 10, 2019 at 03:51:42PM -0600, Simon Glass wrote:
> On Fri, 8 Mar 2019 at 13:11, Thierry Reding <thierry.reding@gmail.com> wrote:
> >
> > From: Thierry Reding <treding@nvidia.com>
> >
> > This function can be used to add subnodes in the /reserved-memory node.
> >
> > Signed-off-by: Thierry Reding <treding@nvidia.com>
> > ---
> >  include/fdtdec.h |  17 +++++
> >  lib/fdtdec.c     | 158 +++++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 175 insertions(+)
> >
> 
> I think an example would be useful, or perhaps a pointer to some docs
> (perhaps DT spec?) showing how this function is used?

Yeah, I can add a pointer to the DT bindings. Do you want me to add a
copy of the DT bindings to the U-Boot source tree, or is it sufficient
to refer to the docs in Linux?

As for an example, patches 5 and 6 show how this should be used. Do you
want an additional example in the comment, or what did you have in mind?

Thierry

> Reviewed-by: Simon Glass <sjg@chromium.org>
> 
> 
> 
> > diff --git a/include/fdtdec.h b/include/fdtdec.h
> > index 997103a87cdf..5c9108ced571 100644
> > --- a/include/fdtdec.h
> > +++ b/include/fdtdec.h
> > @@ -979,6 +979,23 @@ int fdtdec_get_max_phandle(const void *blob, uint32_t *maxp);
> >   */
> >  int fdtdec_set_phandle(void *blob, int node, uint32_t phandle);
> >
> > +/**
> > + * fdtdec_add_reserved_memory() - add or find a reserved-memory node
> > + *
> > + * If a reserved-memory node already exists for the given carveout, a phandle
> > + * for that node will be returned. Otherwise a new node will be created and a
> > + * phandle corresponding to it will be returned.
> > + *
> > + * @param blob         FDT blob
> > + * @param basename     base name of the node to create
> > + * @param carveout     information about the carveout region
> > + * @param phandlep     return location for the phandle of the carveout region
> > + * @return 0 on success or a negative error code on failure
> > + */
> > +int fdtdec_add_reserved_memory(void *blob, const char *basename,
> > +                              const struct fdt_memory *carveout,
> > +                              uint32_t *phandlep);
> > +
> >  /**
> >   * Set up the device tree ready for use
> >   */
> > diff --git a/lib/fdtdec.c b/lib/fdtdec.c
> > index 9195a05d1129..a8b35c144ae0 100644
> > --- a/lib/fdtdec.c
> > +++ b/lib/fdtdec.c
> > @@ -1287,6 +1287,164 @@ int fdtdec_set_phandle(void *blob, int node, uint32_t phandle)
> >         return 0;
> >  }
> >
> > +static int fdtdec_init_reserved_memory(void *blob)
> > +{
> > +       int na, ns, node, err;
> > +       fdt32_t value;
> > +
> > +       /* inherit #address-cells and #size-cells from the root node */
> > +       na = fdt_address_cells(blob, 0);
> > +       ns = fdt_size_cells(blob, 0);
> > +
> > +       node = fdt_add_subnode(blob, 0, "reserved-memory");
> > +       if (node < 0)
> > +               return node;
> > +
> > +       err = fdt_setprop(blob, node, "ranges", NULL, 0);
> > +       if (err < 0)
> > +               return err;
> > +
> > +       value = cpu_to_fdt32(na);
> > +
> > +       err = fdt_setprop(blob, node, "#address-cells", &value, sizeof(value));
> > +       if (err < 0)
> > +               return err;
> > +
> > +       value = cpu_to_fdt32(ns);
> > +
> > +       err = fdt_setprop(blob, node, "#size-cells", &value, sizeof(value));
> > +       if (err < 0)
> > +               return err;
> > +
> > +       return node;
> > +}
> > +
> > +static void fdt_addr_unpack(fdt_addr_t addr, fdt32_t *upper, fdt32_t *lower)
> > +{
> > +#ifdef CONFIG_PHYS_64BIT
> > +       *upper = addr >> 32;
> > +#else
> > +       *upper = 0;
> > +#endif
> > +
> > +       *lower = addr;
> > +}
> > +
> > +static void fdt_size_unpack(fdt_size_t size, fdt32_t *upper, fdt32_t *lower)
> > +{
> > +#ifdef CONFIG_PHYS_64BIT
> > +       *upper = size >> 32;
> > +#else
> > +       *upper = 0;
> > +#endif
> > +
> > +       *lower = size;
> > +}
> > +
> > +int fdtdec_add_reserved_memory(void *blob, const char *basename,
> > +                              const struct fdt_memory *carveout,
> > +                              uint32_t *phandlep)
> > +{
> > +       fdt32_t cells[4] = {}, *ptr = cells;
> > +       uint32_t upper, lower, phandle;
> > +       int parent, node, na, ns, err;
> > +       char name[64];
> > +
> > +       /* create an empty /reserved-memory node if one doesn't exist */
> > +       parent = fdt_path_offset(blob, "/reserved-memory");
> > +       if (parent < 0) {
> > +               parent = fdtdec_init_reserved_memory(blob);
> > +               if (parent < 0)
> > +                       return parent;
> > +       }
> > +
> > +       /* only 1 or 2 #address-cells and #size-cells are supported */
> > +       na = fdt_address_cells(blob, parent);
> > +       if (na < 1 || na > 2)
> > +               return -FDT_ERR_BADNCELLS;
> > +
> > +       ns = fdt_address_cells(blob, parent);
> > +       if (ns < 1 || ns > 2)
> > +               return -FDT_ERR_BADNCELLS;
> > +
> > +       /* find a matching node and return the phandle to that */
> > +       fdt_for_each_subnode(node, blob, parent) {
> > +               const char *name = fdt_get_name(blob, node, NULL);
> > +               phys_addr_t addr, size;
> > +
> > +               addr = fdtdec_get_addr_size(blob, node, "reg", &size);
> > +               if (addr == FDT_ADDR_T_NONE) {
> > +                       printf("failed to read address/size for %s\n", name);
> > +                       continue;
> > +               }
> > +
> > +               if (addr == carveout->start && (addr + size) == carveout->end) {
> > +                       *phandlep = fdt_get_phandle(blob, node);
> > +                       return 0;
> > +               }
> > +       }
> > +
> > +       /*
> > +        * Unpack the start address and generate the name of the new node
> > +        * base on the basename and the unit-address.
> > +        */
> > +       fdt_addr_unpack(carveout->start, &upper, &lower);
> > +
> > +       if (na > 1)
> > +               snprintf(name, sizeof(name), "%s@%x,%x", basename, upper,
> > +                        lower);
> > +       else {
> > +               if (upper) {
> > +                       printf("address %08x:%08x exceeds addressable space\n",
> > +                              upper, lower);
> > +                       return -FDT_ERR_BADVALUE;
> > +               }
> > +
> > +               snprintf(name, sizeof(name), "%s@%x", basename, lower);
> > +       }
> > +
> > +       node = fdt_add_subnode(blob, parent, name);
> > +       if (node < 0)
> > +               return node;
> > +
> > +       /*
> > +        * Generate a new phandle for the reserved-memory node. Look up the
> > +        * highest phandle number currently in used and use the next higher
> > +        * one.
> > +        */
> > +       err = fdtdec_get_max_phandle(blob, &phandle);
> > +       if (err < 0)
> > +               return err;
> > +
> > +       err = fdtdec_set_phandle(blob, node, phandle + 1);
> > +       if (err < 0)
> > +               return err;
> > +
> > +       /* store one or two address cells */
> > +       if (na > 1)
> > +               *ptr++ = cpu_to_fdt32(upper);
> > +
> > +       *ptr++ = cpu_to_fdt32(lower);
> > +
> > +       /* store one or two size cells */
> > +       fdt_size_unpack(carveout->end - carveout->start, &upper, &lower);
> > +
> > +       if (ns > 1)
> > +               *ptr++ = cpu_to_fdt32(upper);
> > +
> > +       *ptr++ = cpu_to_fdt32(lower);
> > +
> > +       err = fdt_setprop(blob, node, "reg", cells, ptr - cells);
> > +       if (err < 0)
> > +               return err;
> > +
> > +       /* return the phandle for the new node for the caller to use */
> > +       if (phandlep)
> > +               *phandlep = phandle + 1;
> > +
> > +       return 0;
> > +}
> > +
> >  int fdtdec_setup(void)
> >  {
> >  #if CONFIG_IS_ENABLED(OF_CONTROL)
> > --
> > 2.20.1
> >
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