On Wed, Jun 07, 2017 at 12:50:48PM -0500, Dave Gerlach wrote: > From: Benjamin Fair <b-fair@xxxxxx> > > This patch extends the capability of libfdt to parse the contents of device > trees in a similar manner to fdt_address_cells and fdt_size_cells. > > It adds a helper function which reads the address and size of a device from > the reg property and performs basic sanity checks. > > It does not perform translation to a physical address using the ranges > properties of parents, but this enhancement may be added as a separate > function in the future. > > Signed-off-by: Benjamin Fair <b-fair@xxxxxx> > Reviewed-by: Simon Glass <sjg@xxxxxxxxxxxx> > Signed-off-by: Dave Gerlach <d-gerlach@xxxxxx> Good in concept, but some flaws in implementation; see below. > --- > > This is a rebase and resend of v2 found here [1] which never received > any comments. v2 was resent rather than v3 because of this comment [2] > from David Gibson. Sorry, I've been really busy and didn't get around to review. > > [1] https://www.spinics.net/lists/devicetree-compiler/msg00970.html > [2] https://www.spinics.net/lists/devicetree-compiler/msg01067.html > > libfdt/fdt_addresses.c | 62 ++++++++++++++++++++++++++++++++++++++++++ > libfdt/libfdt.h | 33 ++++++++++++++++++++++ > libfdt/version.lds | 1 + > tests/.gitignore | 1 + > tests/Makefile.tests | 2 +- > tests/addr_size.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++ > tests/addresses.dts | 11 ++++++++ > tests/run_tests.sh | 1 + > 8 files changed, 184 insertions(+), 1 deletion(-) > create mode 100644 tests/addr_size.c > > diff --git a/libfdt/fdt_addresses.c b/libfdt/fdt_addresses.c > index eff4dbcc729d..92cbed95f8ba 100644 > --- a/libfdt/fdt_addresses.c > +++ b/libfdt/fdt_addresses.c > @@ -55,6 +55,9 @@ > > #include "libfdt_internal.h" > > +#define BYTES_PER_CELL 4 > +#define BITS_PER_CELL 32 We've generally used sizeof(fdt32_t) rather than having a define for this. BITS_PER_CELL can be derived. > int fdt_address_cells(const void *fdt, int nodeoffset) > { > const fdt32_t *ac; > @@ -94,3 +97,62 @@ int fdt_size_cells(const void *fdt, int nodeoffset) > > return val; > } > + > +static uint64_t _fdt_read_cells(const fdt32_t *cells, int n) > +{ > + int i; > + uint64_t res; > + > + /* TODO: Support values larger than 2 cells */ > + if (n > 2) > + return -FDT_ERR_BADNELLS; This isn't safe: -FDT_ERR_BADNCELLS will be come a valid uint64_t value. You'll need a return value for just the error and a reference parameter for the value. > + > + res = 0; > + for (i = 0; i < n; i++) { > + res <<= BITS_PER_CELL; > + res |= fdt32_to_cpu(cells[i]); > + } > + > + return res; > +} > + > +int fdt_simple_addr_size(const void *fdt, int nodeoffset, int idx, > + uintptr_t *addr, size_t *size) I don't think uintptr_t is right. There's no reason an address space somewhere in the DT couldn't have bigger addresses than the C environment where libfdt is running. uint64_t would be better. Same argument for size_t, I think. > +{ > + int parent; > + int ac, sc, reg_stride; > + int res; > + const fdt32_t *reg; > + > + reg = fdt_getprop(fdt, nodeoffset, "reg", &res); > + if (res < 0) > + return res; > + > + parent = fdt_parent_offset(fdt, nodeoffset); > + if (parent < 0) > + return res; The error codes from fdt_parent_offset() won't necessarily make sense returned directly in this context. e.g. if you pass the root node here, you'll get a NOTFOUND from parent_offset() which is a bit weird, since the root node definitely exists. You probably want some error translation here. > + ac = fdt_address_cells(fdt, parent); > + if (ac < 0) > + return ac; > + > + sc = fdt_size_cells(fdt, parent); > + if (sc < 0) > + return sc; > + > + reg_stride = ac + sc; > + /* > + * res is the number of bytes read and must be an even multiple of the > + * sum of ac and sc. > + */ > + if ((res % (reg_stride * BYTES_PER_CELL)) != 0) > + return -FDT_ERR_BADVALUE; > + > + if (addr) > + *addr = (uintptr_t) _fdt_read_cells(®[reg_stride * idx], ac); > + if (size) > + *size = (size_t) _fdt_read_cells(®[ac + reg_stride * idx], > + sc); You don't check for errors returned by _fdt_read_cells(), or for ac/sc bigger than sizeof(uinptr_t)/sizeof(size_t). > + return 0; > +} > diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h > index a248b1b57a97..60da2b97d048 100644 > --- a/libfdt/libfdt.h > +++ b/libfdt/libfdt.h > @@ -1098,6 +1098,39 @@ int fdt_address_cells(const void *fdt, int nodeoffset); > */ > int fdt_size_cells(const void *fdt, int nodeoffset); > > +/** > + * > + * fdt_simple_addr_size - read address and/or size from the reg property of a > + * device node. > + * @fdt: pointer to the device tree blob > + * @nodeoffset: offset of the node to find the address and/or size from > + * @idx: which address/size pair to read > + * @addrp: pointer to where address will be stored (will be overwritten) or NULL > + * @sizep: pointer to where size will be stored (will be overwritten) or NULL > + * > + * When the node has a valid reg property, returns the address and/or size > + * values stored there. It does not perform any type of translation based on > + * the parent bus(es). > + * > + * NOTE: This function is expensive, as it must scan the device tree > + * structure from the start to nodeoffset, *twice*, with fdt_parent_offset. > + * > + * returns: > + * 0, on success > + * -FDT_ERR_BADVALUE, if there is an unexpected number of entries in the > + * reg property > + * -FDT_ERR_NOTFOUND, if the node does not have a reg property > + * -FDT_ERR_BADNCELLS, if the number of address or size cells is invalid > + * or greater than 2 (which is the maximum currently supported) > + * -FDT_ERR_BADMAGIC, > + * -FDT_ERR_BADSTATE, > + * -FDT_ERR_BADSTRUCTURE, > + * -FDT_ERR_BADVERSION, > + * -FDT_ERR_TRUNCATED, standard meanings > + */ > + > +int fdt_simple_addr_size(const void *fdt, int nodeoffset, int idx, > + uintptr_t *addrp, size_t *sizep); > > /**********************************************************************/ > /* Write-in-place functions */ > diff --git a/libfdt/version.lds b/libfdt/version.lds > index cff0358f2314..075ffab44ef3 100644 > --- a/libfdt/version.lds > +++ b/libfdt/version.lds > @@ -59,6 +59,7 @@ LIBFDT_1.2 { > fdt_next_subnode; > fdt_address_cells; > fdt_size_cells; > + fdt_simple_addr_size; > fdt_stringlist_contains; > fdt_resize; > fdt_overlay_apply; > diff --git a/tests/.gitignore b/tests/.gitignore > index 9e209d5cbe6b..acb9335e16c8 100644 > --- a/tests/.gitignore > +++ b/tests/.gitignore > @@ -43,6 +43,7 @@ tmp.* > /path_offset > /path_offset_aliases > /phandle_format > +/addr_size > /property_iterate > /propname_escapes > /references > diff --git a/tests/Makefile.tests b/tests/Makefile.tests > index 22581359623c..71a5807baf62 100644 > --- a/tests/Makefile.tests > +++ b/tests/Makefile.tests > @@ -8,7 +8,7 @@ LIB_TESTS_L = get_mem_rsv \ > char_literal \ > sized_cells \ > notfound \ > - addr_size_cells \ > + addr_size_cells addr_size \ > stringlist \ > setprop_inplace nop_property nop_node \ > sw_tree1 \ > diff --git a/tests/addr_size.c b/tests/addr_size.c > new file mode 100644 > index 000000000000..8463efc416c4 > --- /dev/null > +++ b/tests/addr_size.c > @@ -0,0 +1,74 @@ > +/* > + * libfdt - Flat Device Tree manipulation > + * Testcase for address and size handling > + * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/ > + * > + * Based on addr_size_cells.c by David Gibson, <david@xxxxxxxxxxxxxxxxxxxxx> > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU Lesser General Public License as published by > + * the Free Software Foundation; either version 2.1 of the License, or (at > + * your option) any later version. > + * > + * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind, > + * whether express or implied; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * Lesser General Public License for more details. > + */ > + > +#include <stdlib.h> > +#include <stdio.h> > +#include <string.h> > +#include <stdint.h> > + > +#include <libfdt.h> > + > +#include "tests.h" > +#include "testdata.h" > + > +static void check_node(const void *fdt, const char *path, int idx, > + uintptr_t addr, size_t size) > +{ > + int offset, res; > + uintptr_t xaddr; > + uintptr_t xsize; > + > + offset = fdt_path_offset(fdt, path); > + if (offset < 0) > + FAIL("Couldn't find path %s", path); > + > + res = fdt_simple_addr_size(fdt, offset, idx, &xaddr, &xsize); > + if (res < 0) > + FAIL("fdt_simple_addr_size gave error: %s", fdt_strerror(res)); > + > + if (xaddr != addr) > + FAIL("Physical address for %s is %p instead of %p\n", > + path, (void *) xaddr, (void *) addr); > + > + if (xsize != size) > + FAIL("Size for %s is %zx instead of %zx\n", > + path, xsize, size); > +} > + > +int main(int argc, char *argv[]) > +{ > + void *fdt; > + > + if (argc != 2) > + CONFIG("Usage: %s <dtb file>\n", argv[0]); > + > + test_init(argc, argv); > + fdt = load_blob(argv[1]); > + > + check_node(fdt, "/identity-bus@0/id-device@400", 0, > + 0x400, 0x100); > + check_node(fdt, "/simple-bus@1000000/sb-device@8000000800", 0, > + 0x8000000800, 0x200); > + check_node(fdt, "/identity-bus@0/id-device@400", 1, > + 0x400000000, 0x100000030); > + check_node(fdt, "/simple-bus@1000000/sb-device@8000000800", 1, > + 0x70000000, 0x700); > + check_node(fdt, "/simple-bus@1000000/sb-device@8000000800", 2, > + 0x1050000000, 0x20); > + PASS(); > +} Would probably be good to have some tests for graceful behaviour in error cases as well. > diff --git a/tests/addresses.dts b/tests/addresses.dts > index a2faaf59fd7a..32c43795d67d 100644 > --- a/tests/addresses.dts > +++ b/tests/addresses.dts > @@ -6,10 +6,21 @@ > #size-cells = <2>; > > identity-bus@0 { > + #address-cells = <2>; > + #size-cells = <2>; > + id-device@400 { > + reg = <0x0 0x00000400 0x0 0x00000100>, > + <0x4 0x00000000 0x1 0x00000030>; > + }; > }; > > simple-bus@1000000 { > #address-cells = <2>; > #size-cells = <1>; > + sb-device@8000000800 { > + reg = <0x80 0x00000800 0x200>, > + <0x00 0x70000000 0x700>, > + <0x10 0x50000000 0x020>; > + }; > }; > }; > diff --git a/tests/run_tests.sh b/tests/run_tests.sh > index 5df148048758..924db6adfb5a 100755 > --- a/tests/run_tests.sh > +++ b/tests/run_tests.sh > @@ -285,6 +285,7 @@ libfdt_tests () { > > run_dtc_test -I dts -O dtb -o addresses.test.dtb addresses.dts > run_test addr_size_cells addresses.test.dtb > + run_test addr_size addresses.test.dtb > > run_dtc_test -I dts -O dtb -o stringlist.test.dtb stringlist.dts > run_test stringlist stringlist.test.dtb -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
Attachment:
signature.asc
Description: PGP signature
