From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v7 44/50] drivers/of: Split unflatten_dt_node() Date: Wed, 4 Nov 2015 12:43:08 -0600 Message-ID: References: <1446642770-4681-1-git-send-email-gwshan@linux.vnet.ibm.com> <1446642770-4681-45-git-send-email-gwshan@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <1446642770-4681-45-git-send-email-gwshan@linux.vnet.ibm.com> Sender: linux-pci-owner@vger.kernel.org To: Gavin Shan Cc: linuxppc-dev , "linux-pci@vger.kernel.org" , "devicetree@vger.kernel.org" , Benjamin Herrenschmidt , Michael Ellerman , aik@ozlabs.ru, Bjorn Helgaas , Grant Likely , Pantelis Antoniou , Frank Rowand List-Id: devicetree@vger.kernel.org On Wed, Nov 4, 2015 at 7:12 AM, Gavin Shan wrote: > The function unflatten_dt_node() is called recursively to unflatten > device nodes and properties in the FDT blob. It looks complicated > and hard to be understood. > > This splits the function into 3 functions: populate_properties(), > populate_node() and unflatten_dt_node(). populate_properties(), > which is called by populate_node(), creates properties for the > indicated device node. The later one creates the device nodes > from FDT blob. populate_node() gets the offset in FDT blob for > next device nodes and then calls populate_node(). No logical > changes introduced. > > Signed-off-by: Gavin Shan > --- > drivers/of/fdt.c | 275 ++++++++++++++++++++++++++++++++----------------------- > 1 file changed, 160 insertions(+), 115 deletions(-) > > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > index 6e82bc42..173b036 100644 > --- a/drivers/of/fdt.c > +++ b/drivers/of/fdt.c > @@ -160,39 +160,127 @@ static void *unflatten_dt_alloc(void **mem, unsigned long size, > return res; > } > > -/** > - * unflatten_dt_node - Alloc and populate a device_node from the flat tree > - * @blob: The parent device tree blob > - * @mem: Memory chunk to use for allocating device nodes and properties > - * @poffset: pointer to node in flat tree > - * @dad: Parent struct device_node > - * @nodepp: The device_node tree created by the call > - * @fpsize: Size of the node path up at the current depth. > - * @dryrun: If true, do not allocate device nodes but still calculate needed > - * memory size > - */ > -static void * unflatten_dt_node(const void *blob, > - void *mem, > - int *poffset, > - struct device_node *dad, > - struct device_node **nodepp, > - unsigned long fpsize, > +static void populate_properties(const void *blob, > + int offset, > + void **mem, > + struct device_node *np, > + const char *nodename, > bool dryrun) I'd like to make dryrun implicit. It is basically a function of NULL or near NULL pointers. > { > - const __be32 *p; > + struct property *pp, **pprev = NULL; > + int cur; > + bool has_name = false; > + > + pprev = &np->properties; > + cur = fdt_first_property_offset(blob, offset); > + while (cur >= 0) { This could be better written as a for loop to avoid the gotos: for (cur = fdt_first_property_offset(blob, offset); cur >=0; cur = fdt_next_property_offset(blob, cur)) > + const __be32 *val; > + const char *pname; > + u32 sz; > + > + val = fdt_getprop_by_offset(blob, cur, &pname, &sz); > + if (!val) { > + pr_warn("%s: Cannot locate property at 0x%x\n", > + __func__, cur); > + goto next; > + } > + > + if (!pname) { > + pr_warn("%s: Cannot find property name at 0x%x\n", > + __func__, cur); > + goto next; > + } else if (!strcmp(pname, "name")) { > + has_name = true; > + } > + > + pp = unflatten_dt_alloc(mem, sizeof(struct property), > + __alignof__(struct property)); > + if (!dryrun) { Then: if (dryrun) continue; to save some indentation and vertical code. > + /* We accept flattened tree phandles either in > + * ePAPR-style "phandle" properties, or the > + * legacy "linux,phandle" properties. If both > + * appear and have different values, things > + * will get weird. Don't do that. > + */ > + if (!strcmp(pname, "phandle") || > + !strcmp(pname, "linux,phandle")) { > + if (!np->phandle) > + np->phandle = be32_to_cpup(val); > + } > + > + /* And we process the "ibm,phandle" property > + * used in pSeries dynamic device tree > + * stuff > + */ > + if (!strcmp(pname, "ibm,phandle")) > + np->phandle = be32_to_cpup(val); > + > + pp->name = (char *)pname; > + pp->length = sz; > + pp->value = (__be32 *)val; > + *pprev = pp; > + pprev = &pp->next; > + } > +next: > + cur = fdt_next_property_offset(blob, cur); > + } > + > + /* With version 0x10 we may not have the name property, > + * recreate it here from the unit name if absent > + */ > + if (!has_name) { > + const char *p = nodename, *ps = p, *pa = NULL; > + int len; > + > + while (*p) { > + if ((*p) == '@') > + pa = p; > + else if ((*p) == '/') > + ps = p + 1; > + p++; > + } > + > + if (pa < ps) > + pa = p; > + len = (pa - ps) + 1; > + pp = unflatten_dt_alloc(mem, sizeof(struct property) + len, > + __alignof__(struct property)); > + if (!dryrun) { > + pp->name = "name"; > + pp->length = len; > + pp->value = pp + 1; > + *pprev = pp; > + pprev = &pp->next; > + memcpy(pp->value, ps, len - 1); > + ((char *)pp->value)[len - 1] = 0; > + pr_debug("fixed up name for %s -> %s\n", > + nodename, (char *)pp->value); > + } > + } > + > + if (!dryrun) > + *pprev = NULL; > +} > + > +static unsigned long populate_node(const void *blob, > + int offset, > + void **mem, > + struct device_node *dad, > + unsigned long fpsize, > + struct device_node **pnp, > + bool dryrun) I think dryrun could be implied here too. > +{ > struct device_node *np; > - struct property *pp, **prev_pp = NULL; > const char *pathp; > unsigned int l, allocl; > - static int depth = 0; > - int old_depth; > - int offset; > - int has_name = 0; > - int new_format = 0; > + bool new_format = false; > + char *fname; > > - pathp = fdt_get_name(blob, *poffset, &l); > - if (!pathp) > - return mem; > + pathp = fdt_get_name(blob, offset, &l); > + if (!pathp) { > + *pnp = NULL; Can't pnp be NULL? > + return 0; > + } > > allocl = ++l; > > @@ -202,7 +290,7 @@ static void * unflatten_dt_node(const void *blob, > * not '/'. > */ > if ((*pathp) != '/') { > - new_format = 1; > + new_format = true; > if (fpsize == 0) { > /* root node: special case. fpsize accounts for path > * plus terminating zero. root node only has '/', so > @@ -222,112 +310,38 @@ static void * unflatten_dt_node(const void *blob, > } > } > > - np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl, > + np = unflatten_dt_alloc(mem, sizeof(struct device_node) + allocl, > __alignof__(struct device_node)); > if (!dryrun) { > - char *fn; > of_node_init(np); > - np->full_name = fn = ((char *)np) + sizeof(*np); > + np->full_name = fname = ((char *)np) + sizeof(*np); If you kept "fn" that would cut down the diff and make it a bit easier to review. > if (new_format) { > - /* rebuild full path for new format */ > + /* Rebuild full path for new format */ > if (dad && dad->parent) { > - strcpy(fn, dad->full_name); > + strcpy(fname, dad->full_name); > #ifdef DEBUG > - if ((strlen(fn) + l + 1) != allocl) { > + if ((strlen(fname) + l + 1) != allocl) { > pr_debug("%s: p: %d, l: %d, a: %d\n", > - pathp, (int)strlen(fn), > - l, allocl); > + pathp, (int)strlen(fn), This won't compile if enabled (should be fname). > + l, allocl); > } > #endif > - fn += strlen(fn); > + fname += strlen(fname); > } > - *(fn++) = '/'; > + *(fname++) = '/'; > } > - memcpy(fn, pathp, l); > + memcpy(fname, pathp, l); > > - prev_pp = &np->properties; > - if (dad != NULL) { > + if (dad) { > np->parent = dad; > np->sibling = dad->child; > dad->child = np; > } > } > - /* process properties */ > - for (offset = fdt_first_property_offset(blob, *poffset); > - (offset >= 0); > - (offset = fdt_next_property_offset(blob, offset))) { > - const char *pname; > - u32 sz; > > - if (!(p = fdt_getprop_by_offset(blob, offset, &pname, &sz))) { > - offset = -FDT_ERR_INTERNAL; > - break; > - } > - > - if (pname == NULL) { > - pr_info("Can't find property name in list !\n"); > - break; > - } > - if (strcmp(pname, "name") == 0) > - has_name = 1; > - pp = unflatten_dt_alloc(&mem, sizeof(struct property), > - __alignof__(struct property)); > - if (!dryrun) { > - /* We accept flattened tree phandles either in > - * ePAPR-style "phandle" properties, or the > - * legacy "linux,phandle" properties. If both > - * appear and have different values, things > - * will get weird. Don't do that. */ > - if ((strcmp(pname, "phandle") == 0) || > - (strcmp(pname, "linux,phandle") == 0)) { > - if (np->phandle == 0) > - np->phandle = be32_to_cpup(p); > - } > - /* And we process the "ibm,phandle" property > - * used in pSeries dynamic device tree > - * stuff */ > - if (strcmp(pname, "ibm,phandle") == 0) > - np->phandle = be32_to_cpup(p); > - pp->name = (char *)pname; > - pp->length = sz; > - pp->value = (__be32 *)p; > - *prev_pp = pp; > - prev_pp = &pp->next; > - } > - } > - /* with version 0x10 we may not have the name property, recreate > - * it here from the unit name if absent > - */ > - if (!has_name) { > - const char *p1 = pathp, *ps = pathp, *pa = NULL; > - int sz; > - > - while (*p1) { > - if ((*p1) == '@') > - pa = p1; > - if ((*p1) == '/') > - ps = p1 + 1; > - p1++; > - } > - if (pa < ps) > - pa = p1; > - sz = (pa - ps) + 1; > - pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz, > - __alignof__(struct property)); > - if (!dryrun) { > - pp->name = "name"; > - pp->length = sz; > - pp->value = pp + 1; > - *prev_pp = pp; > - prev_pp = &pp->next; > - memcpy(pp->value, ps, sz - 1); > - ((char *)pp->value)[sz - 1] = 0; > - pr_debug("fixed up name for %s -> %s\n", pathp, > - (char *)pp->value); > - } > - } > + /* Populate the properties */ Kind of a useless comment. > + populate_properties(blob, offset, mem, np, pathp, dryrun); > if (!dryrun) { > - *prev_pp = NULL; > np->name = of_get_property(np, "name", NULL); > np->type = of_get_property(np, "device_type", NULL); > > @@ -337,6 +351,37 @@ static void * unflatten_dt_node(const void *blob, > np->type = ""; > } > > + *pnp = np; > + return fpsize; > +} > + > +/** > + * unflatten_dt_node - Alloc and populate a device_node from the flat tree > + * @blob: The parent device tree blob > + * @mem: Memory chunk to use for allocating device nodes and properties > + * @poffset: pointer to node in flat tree > + * @dad: Parent struct device_node > + * @nodepp: The device_node tree created by the call > + * @fpsize: Size of the node path up at the current depth. > + * @dryrun: If true, do not allocate device nodes but still calculate needed > + * memory size > + */ > +static void *unflatten_dt_node(const void *blob, > + void *mem, > + int *poffset, > + struct device_node *dad, > + struct device_node **nodepp, > + unsigned long fpsize, > + bool dryrun) > +{ > + struct device_node *np; > + static int depth; > + int old_depth; > + > + fpsize = populate_node(blob, *poffset, &mem, dad, fpsize, &np, dryrun); Doesn't this give a warning assigning a ptr to long? Looks like np can be moved internal to populate_node. > + if (!fpsize) > + return mem; > + > old_depth = depth; > *poffset = fdt_next_node(blob, *poffset, &depth); > if (depth < 0) > -- > 2.1.0 >