sparc: break out some prom device-tree building code out into drivers/of
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From: Grant Likely on 29 Jun 2010 04:00 On Mon, Jun 28, 2010 at 7:00 PM, Andres Salomon <dilinger(a)queued.net> wrote: > > Stick code into drivers/of/pdt.c (Prom Device Tree) that other > architectures with OpenFirmware resident in memory can make use of. > > Signed-off-by: Andres Salomon <dilinger(a)queued.net> Hi Andres, The patch itself looks fine, but there are currently two methods for extracting the device tree from open firmware; one in arch/powerpc using the flattened format, and one in arch/sparc. I don't want to end up maintaining both methods in drivers/of, and there has also some discussions on moving the powerpc version into common code. I've been thinking about using the powerpc approach to support ARM platforms using both the flat tree and real OFW. Ben, what say you? Before I do anything I'd like to have your opinion. Cheers, g. > --- > �arch/sparc/Kconfig � � � � � � �| � �1 + > �arch/sparc/include/asm/prom.h � | � 15 +++- > �arch/sparc/kernel/prom.h � � � �| � 14 --- > �arch/sparc/kernel/prom_common.c | �173 +------------------------------ > �drivers/of/Kconfig � � � � � � �| � �4 + > �drivers/of/Makefile � � � � � � | � �1 + > �drivers/of/pdt.c � � � � � � � �| �225 +++++++++++++++++++++++++++++++++++++++ > �include/linux/of_pdt.h � � � � �| � 37 +++++++ > �8 files changed, 282 insertions(+), 188 deletions(-) > �create mode 100644 drivers/of/pdt.c > �create mode 100644 include/linux/of_pdt.h > > diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig > index 6f1470b..b4cb63b 100644 > --- a/arch/sparc/Kconfig > +++ b/arch/sparc/Kconfig > @@ -150,6 +150,7 @@ config ARCH_NO_VIRT_TO_BUS > > �config OF > � � � �def_bool y > + � � � select OF_PROMTREE > > �config ARCH_SUPPORTS_DEBUG_PAGEALLOC > � � � �def_bool y if SPARC64 > diff --git a/arch/sparc/include/asm/prom.h b/arch/sparc/include/asm/prom.h > index f845828..0834c2a 100644 > --- a/arch/sparc/include/asm/prom.h > +++ b/arch/sparc/include/asm/prom.h > @@ -18,6 +18,7 @@ > �* 2 of the License, or (at your option) any later version. > �*/ > �#include <linux/types.h> > +#include <linux/of_pdt.h> > �#include <linux/proc_fs.h> > �#include <linux/mutex.h> > �#include <asm/atomic.h> > @@ -65,8 +66,18 @@ extern struct device_node *of_console_device; > �extern char *of_console_path; > �extern char *of_console_options; > > -extern void (*prom_build_more)(struct device_node *dp, struct device_node ***nextp); > -extern char *build_full_name(struct device_node *dp); > +/* stuff used by of/pdt */ > +extern void * prom_early_alloc(unsigned long size); > +extern void irq_trans_init(struct device_node *dp); > +extern char *build_path_component(struct device_node *dp); > + > +extern char *prom_firstprop(int node, char *buffer); > +extern char *prom_nextprop(int node, const char *oprop, char *buffer); > +extern int prom_getproplen(int node, const char *prop); > +extern int prom_getproperty(int node, const char *prop, > + � � � � � � � � � � � � � char *buffer, int bufsize); > +extern int prom_getchild(int node); > +extern int prom_getsibling(int node); > > �#endif /* __KERNEL__ */ > �#endif /* _SPARC_PROM_H */ > diff --git a/arch/sparc/kernel/prom.h b/arch/sparc/kernel/prom.h > index a8591ef..cf5fe1c 100644 > --- a/arch/sparc/kernel/prom.h > +++ b/arch/sparc/kernel/prom.h > @@ -4,20 +4,6 @@ > �#include <linux/spinlock.h> > �#include <asm/prom.h> > > -extern void * prom_early_alloc(unsigned long size); > -extern void irq_trans_init(struct device_node *dp); > - > -extern unsigned int prom_unique_id; > - > -static inline int is_root_node(const struct device_node *dp) > -{ > - � � � if (!dp) > - � � � � � � � return 0; > - > - � � � return (dp->parent == NULL); > -} > - > -extern char *build_path_component(struct device_node *dp); > �extern void of_console_init(void); > > �extern unsigned int prom_early_allocated; > diff --git a/arch/sparc/kernel/prom_common.c b/arch/sparc/kernel/prom_common.c > index 57ac9e2..fc990e1 100644 > --- a/arch/sparc/kernel/prom_common.c > +++ b/arch/sparc/kernel/prom_common.c > @@ -20,14 +20,13 @@ > �#include <linux/mutex.h> > �#include <linux/slab.h> > �#include <linux/of.h> > +#include <linux/of_pdt.h> > �#include <asm/prom.h> > �#include <asm/oplib.h> > �#include <asm/leon.h> > > �#include "prom.h" > > -void (*prom_build_more)(struct device_node *dp, struct device_node ***nextp); > - > �struct device_node *of_console_device; > �EXPORT_SYMBOL(of_console_device); > > @@ -119,176 +118,6 @@ int of_find_in_proplist(const char *list, const char *match, int len) > �} > �EXPORT_SYMBOL(of_find_in_proplist); > > -unsigned int prom_unique_id; > - > -static struct property * __init build_one_prop(phandle node, char *prev, > - � � � � � � � � � � � � � � � � � � � � � � �char *special_name, > - � � � � � � � � � � � � � � � � � � � � � � �void *special_val, > - � � � � � � � � � � � � � � � � � � � � � � �int special_len) > -{ > - � � � static struct property *tmp = NULL; > - � � � struct property *p; > - � � � const char *name; > - > - � � � if (tmp) { > - � � � � � � � p = tmp; > - � � � � � � � memset(p, 0, sizeof(*p) + 32); > - � � � � � � � tmp = NULL; > - � � � } else { > - � � � � � � � p = prom_early_alloc(sizeof(struct property) + 32); > - � � � � � � � p->unique_id = prom_unique_id++; > - � � � } > - > - � � � p->name = (char *) (p + 1); > - � � � if (special_name) { > - � � � � � � � strcpy(p->name, special_name); > - � � � � � � � p->length = special_len; > - � � � � � � � p->value = prom_early_alloc(special_len); > - � � � � � � � memcpy(p->value, special_val, special_len); > - � � � } else { > - � � � � � � � if (prev == NULL) { > - � � � � � � � � � � � name = prom_firstprop(node, p->name); > - � � � � � � � } else { > - � � � � � � � � � � � name = prom_nextprop(node, prev, p->name); > - � � � � � � � } > - > - � � � � � � � if (!name || strlen(name) == 0) { > - � � � � � � � � � � � tmp = p; > - � � � � � � � � � � � return NULL; > - � � � � � � � } > -#ifdef CONFIG_SPARC32 > - � � � � � � � strcpy(p->name, name); > -#endif > - � � � � � � � p->length = prom_getproplen(node, p->name); > - � � � � � � � if (p->length <= 0) { > - � � � � � � � � � � � p->length = 0; > - � � � � � � � } else { > - � � � � � � � � � � � int len; > - > - � � � � � � � � � � � p->value = prom_early_alloc(p->length + 1); > - � � � � � � � � � � � len = prom_getproperty(node, p->name, p->value, > - � � � � � � � � � � � � � � � � � � � � � � �p->length); > - � � � � � � � � � � � if (len <= 0) > - � � � � � � � � � � � � � � � p->length = 0; > - � � � � � � � � � � � ((unsigned char *)p->value)[p->length] = '\0'; > - � � � � � � � } > - � � � } > - � � � return p; > -} > - > -static struct property * __init build_prop_list(phandle node) > -{ > - � � � struct property *head, *tail; > - > - � � � head = tail = build_one_prop(node, NULL, > - � � � � � � � � � � � � � � � � � �".node", &node, sizeof(node)); > - > - � � � tail->next = build_one_prop(node, NULL, NULL, NULL, 0); > - � � � tail = tail->next; > - � � � while(tail) { > - � � � � � � � tail->next = build_one_prop(node, tail->name, > - � � � � � � � � � � � � � � � � � � � � � NULL, NULL, 0); > - � � � � � � � tail = tail->next; > - � � � } > - > - � � � return head; > -} > - > -static char * __init get_one_property(phandle node, const char *name) > -{ > - � � � char *buf = "<NULL>"; > - � � � int len; > - > - � � � len = prom_getproplen(node, name); > - � � � if (len > 0) { > - � � � � � � � buf = prom_early_alloc(len); > - � � � � � � � len = prom_getproperty(node, name, buf, len); > - � � � } > - > - � � � return buf; > -} > - > -static struct device_node * __init prom_create_node(phandle node, > - � � � � � � � � � � � � � � � � � � � � � � � � � struct device_node *parent) > -{ > - � � � struct device_node *dp; > - > - � � � if (!node) > - � � � � � � � return NULL; > - > - � � � dp = prom_early_alloc(sizeof(*dp)); > - � � � dp->unique_id = prom_unique_id++; > - � � � dp->parent = parent; > - > - � � � kref_init(&dp->kref); > - > - � � � dp->name = get_one_property(node, "name"); > - � � � dp->type = get_one_property(node, "device_type"); > - � � � dp->phandle = node; > - > - � � � dp->properties = build_prop_list(node); > - > - � � � irq_trans_init(dp); > - > - � � � return dp; > -} > - > -char * __init build_full_name(struct device_node *dp) > -{ > - � � � int len, ourlen, plen; > - � � � char *n; > - > - � � � plen = strlen(dp->parent->full_name); > - � � � ourlen = strlen(dp->path_component_name); > - � � � len = ourlen + plen + 2; > - > - � � � n = prom_early_alloc(len); > - � � � strcpy(n, dp->parent->full_name); > - � � � if (!is_root_node(dp->parent)) { > - � � � � � � � strcpy(n + plen, "/"); > - � � � � � � � plen++; > - � � � } > - � � � strcpy(n + plen, dp->path_component_name); > - > - � � � return n; > -} > - > -static struct device_node * __init prom_build_tree(struct device_node *parent, > - � � � � � � � � � � � � � � � � � � � � � � � � �phandle node, > - � � � � � � � � � � � � � � � � � � � � � � � � �struct device_node ***nextp) > -{ > - � � � struct device_node *ret = NULL, *prev_sibling = NULL; > - � � � struct device_node *dp; > - > - � � � while (1) { > - � � � � � � � dp = prom_create_node(node, parent); > - � � � � � � � if (!dp) > - � � � � � � � � � � � break; > - > - � � � � � � � if (prev_sibling) > - � � � � � � � � � � � prev_sibling->sibling = dp; > - > - � � � � � � � if (!ret) > - � � � � � � � � � � � ret = dp; > - � � � � � � � prev_sibling = dp; > - > - � � � � � � � *(*nextp) = dp; > - � � � � � � � *nextp = &dp->allnext; > - > - � � � � � � � dp->path_component_name = build_path_component(dp); > - � � � � � � � dp->full_name = build_full_name(dp); > - > - � � � � � � � dp->child = prom_build_tree(dp, prom_getchild(node), nextp); > - > - � � � � � � � if (prom_build_more) > - � � � � � � � � � � � prom_build_more(dp, nextp); > - > - � � � � � � � node = prom_getsibling(node); > - � � � } > - > - � � � return ret; > -} > - > �unsigned int prom_early_allocated __initdata; > > �void __init prom_build_devicetree(void) > diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig > index 7cecc8f..41921a8 100644 > --- a/drivers/of/Kconfig > +++ b/drivers/of/Kconfig > @@ -2,6 +2,10 @@ config OF_FLATTREE > � � � �bool > � � � �depends on OF > > +config OF_PROMTREE > + � � � bool > + � � � depends on OF > + > �config OF_DYNAMIC > � � � �def_bool y > � � � �depends on OF && PPC_OF > diff --git a/drivers/of/Makefile b/drivers/of/Makefile > index f232cc9..54e8517 100644 > --- a/drivers/of/Makefile > +++ b/drivers/of/Makefile > @@ -1,5 +1,6 @@ > �obj-y = base.o > �obj-$(CONFIG_OF_FLATTREE) += fdt.o > +obj-$(CONFIG_OF_PROMTREE) += pdt.o > �obj-$(CONFIG_OF_DEVICE) += device.o platform.o > �obj-$(CONFIG_OF_GPIO) � += gpio.o > �obj-$(CONFIG_OF_I2C) � += of_i2c.o > diff --git a/drivers/of/pdt.c b/drivers/of/pdt.c > new file mode 100644 > index 0000000..b24167f > --- /dev/null > +++ b/drivers/of/pdt.c > @@ -0,0 +1,225 @@ > +/* > + * Paul Mackerras � � �August 1996. > + * Copyright (C) 1996-2005 Paul Mackerras. > + * > + * �Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner. > + * � �{engebret|bergner}@us.ibm.com > + * > + * �Adapted for sparc by David S. Miller davem(a)davemloft.net > + * �Adapted for multiple architectures by Andres Salomon <dilinger(a)queued.net> > + * > + * � � �This program is free software; you can redistribute it and/or > + * � � �modify it under the terms of the GNU General Public License > + * � � �as published by the Free Software Foundation; either version > + * � � �2 of the License, or (at your option) any later version. > + */ > + > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/errno.h> > +#include <linux/mutex.h> > +#include <linux/slab.h> > +#include <linux/of.h> > +#include <linux/of_pdt.h> > +#include <asm/prom.h> > + > +/* TODO: mark this stuff as __initdata */ > +void (*prom_build_more)(struct device_node *dp, struct device_node ***nextp); > + > +#if defined(CONFIG_SPARC) > +static unsigned int prom_unique_id; > + > +#define inc_unique_id(p) do { \ > + � � � (p)->unique_id = prom_unique_id++; \ > +} while (0) > + > +static inline const char *fetch_node_name(struct device_node *dp) > +{ > + � � � return dp->path_component_name; > +} > + > +#else > + > +#define inc_unique_id(p) � � � do { } while(0) > + > +static inline const char *fetch_node_name(struct device_node *dp) > +{ > + � � � return dp->name; > +} > + > +static inline void irq_trans_init(struct device_node *dp) > +{ > + � � � /* unused on non-SPARC architectures */ > +} > + > +#endif /* !CONFIG_SPARC */ > + > +static struct property * __init build_one_prop(phandle node, char *prev, > + � � � � � � � � � � � � � � � � � � � � � � �char *special_name, > + � � � � � � � � � � � � � � � � � � � � � � �void *special_val, > + � � � � � � � � � � � � � � � � � � � � � � �int special_len) > +{ > + � � � static struct property *tmp = NULL; > + � � � struct property *p; > + � � � const char *name; > + > + � � � if (tmp) { > + � � � � � � � p = tmp; > + � � � � � � � memset(p, 0, sizeof(*p) + 32); > + � � � � � � � tmp = NULL; > + � � � } else { > + � � � � � � � p = prom_early_alloc(sizeof(struct property) + 32); > + � � � � � � � inc_unique_id(p); > + � � � } > + > + � � � p->name = (char *) (p + 1); > + � � � if (special_name) { > + � � � � � � � strcpy(p->name, special_name); > + � � � � � � � p->length = special_len; > + � � � � � � � p->value = prom_early_alloc(special_len); > + � � � � � � � memcpy(p->value, special_val, special_len); > + � � � } else { > + � � � � � � � if (prev == NULL) { > + � � � � � � � � � � � name = prom_firstprop(node, p->name); > + � � � � � � � } else { > + � � � � � � � � � � � name = prom_nextprop(node, prev, p->name); > + � � � � � � � } > + > + � � � � � � � if (!name || strlen(name) == 0) { > + � � � � � � � � � � � tmp = p; > + � � � � � � � � � � � return NULL; > + � � � � � � � } > +#ifdef CONFIG_SPARC32 > + � � � � � � � strcpy(p->name, name); > +#endif > + � � � � � � � p->length = prom_getproplen(node, p->name); > + � � � � � � � if (p->length <= 0) { > + � � � � � � � � � � � p->length = 0; > + � � � � � � � } else { > + � � � � � � � � � � � int len; > + > + � � � � � � � � � � � p->value = prom_early_alloc(p->length + 1); > + � � � � � � � � � � � len = prom_getproperty(node, p->name, p->value, > + � � � � � � � � � � � � � � � � � � � � � � �p->length); > + � � � � � � � � � � � if (len <= 0) > + � � � � � � � � � � � � � � � p->length = 0; > + � � � � � � � � � � � ((unsigned char *)p->value)[p->length] = '\0'; > + � � � � � � � } > + � � � } > + � � � return p; > +} > + > +static struct property * __init build_prop_list(phandle node) > +{ > + � � � struct property *head, *tail; > + > + � � � head = tail = build_one_prop(node, NULL, > + � � � � � � � � � � � � � � � � � �".node", &node, sizeof(node)); > + > + � � � tail->next = build_one_prop(node, NULL, NULL, NULL, 0); > + � � � tail = tail->next; > + � � � while(tail) { > + � � � � � � � tail->next = build_one_prop(node, tail->name, > + � � � � � � � � � � � � � � � � � � � � � NULL, NULL, 0); > + � � � � � � � tail = tail->next; > + � � � } > + > + � � � return head; > +} > + > +static char * __init get_one_property(phandle node, const char *name) > +{ > + � � � char *buf = "<NULL>"; > + � � � int len; > + > + � � � len = prom_getproplen(node, name); > + � � � if (len > 0) { > + � � � � � � � buf = prom_early_alloc(len); > + � � � � � � � len = prom_getproperty(node, name, buf, len); > + � � � } > + > + � � � return buf; > +} > + > +struct device_node * __init prom_create_node(phandle node, > + � � � � � � � � � � � � � � � � � � � � � �struct device_node *parent) > +{ > + � � � struct device_node *dp; > + > + � � � if (!node) > + � � � � � � � return NULL; > + > + � � � dp = prom_early_alloc(sizeof(*dp)); > + � � � inc_unique_id(dp); > + � � � dp->parent = parent; > + > + � � � kref_init(&dp->kref); > + > + � � � dp->name = get_one_property(node, "name"); > + � � � dp->type = get_one_property(node, "device_type"); > + � � � dp->phandle = node; > + > + � � � dp->properties = build_prop_list(node); > + > + � � � irq_trans_init(dp); > + > + � � � return dp; > +} > + > +static char * __init build_full_name(struct device_node *dp) > +{ > + � � � int len, ourlen, plen; > + � � � char *n; > + > + � � � plen = strlen(dp->parent->full_name); > + � � � ourlen = strlen(fetch_node_name(dp)); > + � � � len = ourlen + plen + 2; > + > + � � � n = prom_early_alloc(len); > + � � � strcpy(n, dp->parent->full_name); > + � � � if (!is_root_node(dp->parent)) { > + � � � � � � � strcpy(n + plen, "/"); > + � � � � � � � plen++; > + � � � } > + � � � strcpy(n + plen, fetch_node_name(dp)); > + > + � � � return n; > +} > + > +struct device_node * __init prom_build_tree(struct device_node *parent, > + � � � � � � � � � � � � � � � � � � � � � phandle node, > + � � � � � � � � � � � � � � � � � � � � � struct device_node ***nextp) > +{ > + � � � struct device_node *ret = NULL, *prev_sibling = NULL; > + � � � struct device_node *dp; > + > + � � � while (1) { > + � � � � � � � dp = prom_create_node(node, parent); > + � � � � � � � if (!dp) > + � � � � � � � � � � � break; > + > + � � � � � � � if (prev_sibling) > + � � � � � � � � � � � prev_sibling->sibling = dp; > + > + � � � � � � � if (!ret) > + � � � � � � � � � � � ret = dp; > + � � � � � � � prev_sibling = dp; > + > + � � � � � � � *(*nextp) = dp; > + � � � � � � � *nextp = &dp->allnext; > + > +#if defined(CONFIG_SPARC) > + � � � � � � � dp->path_component_name = build_path_component(dp); > +#endif > + � � � � � � � dp->full_name = build_full_name(dp); > + > + � � � � � � � dp->child = prom_build_tree(dp, prom_getchild(node), nextp); > + > + � � � � � � � if (prom_build_more) > + � � � � � � � � � � � prom_build_more(dp, nextp); > + > + � � � � � � � node = prom_getsibling(node); > + � � � } > + > + � � � return ret; > +} > diff --git a/include/linux/of_pdt.h b/include/linux/of_pdt.h > new file mode 100644 > index 0000000..f62616e > --- /dev/null > +++ b/include/linux/of_pdt.h > @@ -0,0 +1,37 @@ > +#include <linux/of.h> �/* linux/of.h gets to determine #include ordering */ > +/* > + * Definitions for building a device tree by calling into the > + * Open Firmware PROM. > + * > + * Copyright (C) 1996-2005 Paul Mackerras. > + * Copyright (C) 2010 �Andres Salomon <dilinger(a)queued.net> > + * > + * Updates for PPC64 by Peter Bergner & David Engebretsen, IBM Corp. > + * Updates for SPARC by David S. Miller > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * as published by the Free Software Foundation; either version > + * 2 of the License, or (at your option) any later version. > + */ > + > +#ifndef _LINUX_OF_PDT_H > +#define _LINUX_OF_PDT_H > + > +extern struct device_node *prom_create_node(phandle node, > + � � � � � � � � � � � � � � � � � � � � � struct device_node *parent); > +extern struct device_node *prom_build_tree(struct device_node *parent, > + � � � � � � � � � � � � � � � � � � � � �phandle node, > + � � � � � � � � � � � � � � � � � � � � �struct device_node ***nextp); > + > +extern void (*prom_build_more)(struct device_node *dp, struct device_node ***nextp); > + > +static inline int is_root_node(const struct device_node *dp) > +{ > + � � � if (!dp) > + � � � � � � � return 0; > + > + � � � return (dp->parent == NULL); > +} > + > +#endif /* _LINUX_OF_PDT_H */ > -- > 1.5.6.5 > > -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Grant Likely on 29 Jun 2010 17:50 On Tue, Jun 29, 2010 at 9:03 AM, Andres Salomon <dilinger(a)queued.net> wrote: > On Tue, 29 Jun 2010 00:50:08 -0700 > Grant Likely <grant.likely(a)secretlab.ca> wrote: > >> On Mon, Jun 28, 2010 at 7:00 PM, Andres Salomon <dilinger(a)queued.net> wrote: >> > >> > Stick code into drivers/of/pdt.c (Prom Device Tree) that other >> > architectures with OpenFirmware resident in memory can make use of. >> > >> > Signed-off-by: Andres Salomon <dilinger(a)queued.net> >> >> Hi Andres, >> >> The patch itself looks fine, but there are currently two methods for >> extracting the device tree from open firmware; one in arch/powerpc >> using the flattened format, and one in arch/sparc. �I don't want to >> end up maintaining both methods in drivers/of, and there has also some >> discussions on moving the powerpc version into common code. �I've been >> thinking about using the powerpc approach to support ARM platforms >> using both the flat tree and real OFW. >> >> Ben, what say you? �Before I do anything I'd like to have your opinion. >> > > So you're saying that you want ARM (and sparc, and OLPC) to generate a > flat tree by calling into OFW? ARM: yes, it will use the same mechanism as powerpc and microblaze. Direct usage of the flat representation will be more common that machines with real OFW. I'm following the powerpc lead here because the powerpc approach already supports both the flat tree and OFW in the same kernel. Sparc: I don't have a strong opinion. Sparc and PowerPC have a lot of shared code, but they've diverged quite a bit. I have no intention to force a model changes onto sparc. For a lot of the merge work that I'm doing I'm leaving the sparc code as-is in the arch/sparc tree with the assumption that support for new architectures will use the common code in drivers/of. There of course is a gap when it comes to talking to OFW in that both the current powerpc and sparc variants still remain in arch code. x86: I've also just received patches that make use of the flattened representation on x86 for FPGA add in boards. It is conceivable that a single kernel will want support for both OFW and FDT. Since PowerPC already supports this use case, my preference is for the powerpc implementation of OFW. I'm squeamish about having both the powerpc and sparc methods in common drivers/of code, but I'm not saying no. I want to hear from Ben and David who are more familiar with the history before I make a decision. I do know that Ben has been talking about generalizing the powerpc version of the code, and I definitely don't want two methods for extracting the OFW device tree in drivers/of. > Sparc and OLPC have very similar > mechanisms for getting device tree info from OFW, so it makes sense to > share code between them. Other than the flattened tree step; is the powerpc method dissimilar from the Sparc and OLPC method for talking to OFW? (This is not a rhetorical question, I'm want to know if I'm missing some details). The main difference I know about is that OFW can still kept alive at runtime for sparc, which powerpc does not do. However, keeping OFW callable is a separate issue from how to extract the device tree. g. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Grant Likely on 30 Jun 2010 18:00 On Tue, Jun 29, 2010 at 5:36 PM, Andres Salomon <dilinger(a)queued.net> wrote: > On Tue, 29 Jun 2010 15:42:54 -0600 > Grant Likely <grant.likely(a)secretlab.ca> wrote: > >> On Tue, Jun 29, 2010 at 9:03 AM, Andres Salomon <dilinger(a)queued.net> >> wrote: > [...] >> >> > �Sparc and OLPC have very similar >> > mechanisms for getting device tree info from OFW, so it makes sense >> > to share code between them. >> >> Other than the flattened tree step; is the powerpc method dissimilar >> from the Sparc and OLPC method for talking to OFW? �(This is not a >> rhetorical question, I'm want to know if I'm missing some details). >> The main difference I know about is that OFW can still kept alive at >> runtime for sparc, which powerpc does not do. �However, keeping OFW >> callable is a separate issue from how to extract the device tree. >> > > After having a look at powerpc's flatten_device_tree, I don't see any > obvious reason why OLPC couldn't use this Okay. >(though it still strikes me > as weird to go from prom->fdt->dt when the option of prom->dt is > available and less complex). Which is why I didn't simply NACK it out of hand. It is a valid point. I'd probably be happier if both fdt and pdt used a shared set of utility functions for allocating and tying together the device_node data structures. Then at least there would be only one instance of code to deal with the fiddly data structure interconnections. The nice thing about the powerpc version is that the tree can be extracted really early in the boot process, before any of the core kernel infrastructure or memory management is initialized. > Do you already have the patches that put > this into drivers/of/? No. g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Grant Likely on 6 Jul 2010 03:10 On Mon, Jul 5, 2010 at 8:22 PM, David Miller <davem(a)davemloft.net> wrote: > From: Andres Salomon <dilinger(a)queued.net> > Date: Wed, 7 Jul 2010 04:07:34 +0000 > >> �- For the pdt, calling into the prom once for each property/node to >> � �create a fdt, and then unflattening it. �This is better than the >> � �previous option, but I don't think the prom->fdt code will be very >> � �nice. > > I'll need this on sparc64 at some point to support kexec() anyways. > > So at least for sparc you can assume that a something-->fdt translator > is going to exist at some point in the future regardless of what > happens here. Hi David, I'm curious... what are your plans here? Will you be keeping OF alive between kexec()? Will the new kernel get the entire device tree from fdt, or will it still be talking to OF? How will the fdt fragments as Andres described above fit into sparc kexec (as opposed to generating one big tree as in his first option)? Cheers, g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Grant Likely on 6 Jul 2010 04:20
On Tue, Jul 6, 2010 at 1:16 AM, David Miller <davem(a)davemloft.net> wrote: > From: Grant Likely <grant.likely(a)secretlab.ca> > Date: Tue, 6 Jul 2010 01:00:06 -0600 > >> I'm curious... what are your plans here? �Will you be keeping OF alive >> between kexec()? �Will the new kernel get the entire device tree from >> fdt, or will it still be talking to OF? �How will the fdt fragments as >> Andres described above fit into sparc kexec (as opposed to generating >> one big tree as in his first option)? > > On certain sparc64 systems, I have to stop making PROM calls early > in the boot right after I fetch the device tree into the kernel. > > So yes for a kexec() I'll have to pass an fdt or similar to the > child kernel. > > It could be a big linear fdt buffer, or fragments, it really doesn't > matter all that much actually. Okay. There is already support for getting the tree out of the kernel and into fdt form via procfs. Userspace can also modify it before sending it back to kexec(). This will be easy no matter which approach Andres uses. g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |