Hi Michael, On Mon, 24 Feb 2020 at 22:10, Michael Trimarchi <mich...@amarulasolutions.com> wrote: > > The intent is to reserve memory _and_ prevent it from being included > in the kernel's linear map. For thos reason it is also necessary to include > the > 'no-map' property for this reserved-mem node. > > From Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt: > > no-map (optional) - empty property > - Indicates the operating system must not create a virtual mapping > of the region as part of its standard mapping of system memory, > nor permit speculative access to it under any circumstances other > than under the control of the device driver using the region. > > Signed-off-by: Michael Trimarchi <mich...@amarulasolutions.com> > --- > Changes: RFC->v1 > - Add a better commit message > --- > common/fdt_support.c | 40 ++++++++++++++++++++++++++++++++++++++++ > include/fdt_support.h | 11 +++++++++++ > 2 files changed, 51 insertions(+) > > diff --git a/common/fdt_support.c b/common/fdt_support.c > index 02cf5c6241..a3662f4358 100644 > --- a/common/fdt_support.c > +++ b/common/fdt_support.c > @@ -410,6 +410,46 @@ static int fdt_pack_reg(const void *fdt, void *buf, u64 > *address, u64 *size, > return p - (char *)buf; > } > > +int fdt_fixup_reserved_memory(void *blob, const char *area, u64 start[], u64 > size[]) > +{ > + int offs, len; > + const char *subpath; > + const char *path = "/reserved-memory"; > + fdt32_t address_cells = cpu_to_fdt32(fdt_address_cells(blob, 0)); > + fdt32_t size_cells = cpu_to_fdt32(fdt_size_cells(blob, 0)); > + u8 temp[16]; /* Up to 64-bit address + 64-bit size */ > + > + offs = fdt_path_offset(blob, path); > + if (offs < 0) { > + debug("Node %s not found\n", path); > + path = "/"; > + subpath = "reserved-memory"; > + offs = fdt_path_offset(blob, path);
Error check > + offs = fdt_add_subnode(blob, offs, subpath); > + if (offs < 0) { > + printf("Could not create %s%s node.\n", path, > subpath); > + return -1; > + } > + path = "/reserved-memory"; > + offs = fdt_path_offset(blob, path); > + > + fdt_setprop(blob, offs, "#address-cells", &address_cells, > sizeof(address_cells)); > + fdt_setprop(blob, offs, "#size-cells", &size_cells, > sizeof(size_cells)); > + fdt_setprop(blob, offs, "ranges", NULL, 0); Need error-checking on these three > + } > + > + offs = fdt_add_subnode(blob, offs, area ? : "private"); Is this in a binding file somewhere? > + if (offs < 0) { > + printf("Could not create %s%s node.\n", path, subpath); > + return -1; return offs > + } > + > + fdt_setprop(blob, offs, "no-map", NULL, 0); and this? Also needs error check > + len = fdt_pack_reg(blob, temp, start, size, 1); > + fdt_setprop(blob, offs, "reg", temp, len); blank line before return > + return 0; > +} > + > #if CONFIG_NR_DRAM_BANKS > 4 > #define MEMORY_BANKS_MAX CONFIG_NR_DRAM_BANKS > #else > diff --git a/include/fdt_support.h b/include/fdt_support.h > index ba14acd7f6..7c8a280f53 100644 > --- a/include/fdt_support.h > +++ b/include/fdt_support.h > @@ -93,6 +93,17 @@ void do_fixup_by_compat_u32(void *fdt, const char *compat, > */ > int fdt_fixup_memory(void *blob, u64 start, u64 size); > > +/** > + * Setup the memory reserved node in the DT. Creates one if none was > existing before. > + * > + * @param blob FDT blob to update > + * @param area Reserved area name > + * @param start Begin of DRAM mapping in physical memory > + * @param size Size of the single memory bank > + * @return 0 if ok, or -1 or -FDT_ERR_... on error Really we should return an FDT_ERR always. -1 is not a good idea and in fact is an FDT_ERR > + */ > +int fdt_fixup_reserved_memory(void *blob, const char *area, u64 start[], u64 > size[]); > + > /** > * Fill the DT memory node with multiple memory banks. > * Creates the node if none was existing before. > -- > 2.17.1 > Regards, Simon