Re: [PATCH 4/4] x86: OLPC: add OLPC device-tree support

Grant Likely
2010-06-29T08:13:04Z

Hi Andres, comments below....

On Mon, Jun 28, 2010 at 7:00 PM, Andres Salomon <dilinger@queued.net> wrote:
>
> Make use of PROC_DEVICETREE to export the tree, and sparc's PROMTREE code to
> call into OLPC's Open Firmware to build the tree.
>
> (Yes, I know this leaks memory by simply using kmalloc)
>
> Signed-off-by: Andres Salomon <dilinger@queued.net>
> ---
>  arch/x86/Kconfig                 |    5 ++
>  arch/x86/include/asm/olpc_prom.h |   42 +++++++++++
>  arch/x86/include/asm/prom.h      |    5 ++
>  arch/x86/kernel/Makefile         |    1 +
>  arch/x86/kernel/olpc_ofw.c       |   13 ++++
>  arch/x86/kernel/olpc_prom.c      |  148 ++++++++++++++++++++++++++++++++++++++
>  fs/proc/Kconfig                  |    2 +-
>  7 files changed, 215 insertions(+), 1 deletions(-)
>  create mode 100644 arch/x86/include/asm/olpc_prom.h
>  create mode 100644 arch/x86/include/asm/prom.h
>  create mode 100644 arch/x86/kernel/olpc_prom.c
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 71c194d..7aea004 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2071,6 +2071,11 @@ config OLPC_OPENFIRMWARE
>          that is used on the OLPC XO-1 Children's Machine.
>          If unsure, say N here.
>
> +config OF
> +       def_bool y
> +       depends on OLPC_OPENFIRMWARE
> +       select OF_PROMTREE
> +

This hunk will need to be respun on top of Stephen's CONFIG_OF change.
It's currently in my test-devicetree branch on
git://git.secretlab.ca/git/linux-2.6

>  endif # X86_32
>
>  config K8_NB
> diff --git a/arch/x86/include/asm/olpc_prom.h b/arch/x86/include/asm/olpc_prom.h
> new file mode 100644
> index 0000000..96cdcee
> --- /dev/null
> +++ b/arch/x86/include/asm/olpc_prom.h
> @@ -0,0 +1,42 @@
> +#include <linux/of.h>  /* linux/of.h gets to determine #include ordering */
> +/*
> + * Definitions for talking to the Open Firmware PROM on
> + * Power Macintosh computers.
> + *
> + * Copyright (C) 1996-2005 Paul Mackerras.
> + *
> + * Updates for PPC64 by Peter Bergner & David Engebretsen, IBM Corp.
> + * Updates for SPARC by David S. Miller
> + * Updates for x86/OLPC by Andres Salomon
> + *
> + * 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 _X86_PROM_OLPC_H
> +#define _X86_PROM_OLPC_H
> +#ifdef __KERNEL__
> +
> +#define OF_ROOT_NODE_ADDR_CELLS_DEFAULT 2
> +#define OF_ROOT_NODE_SIZE_CELLS_DEFAULT 1

Do you really need to override these from the default?

> +#define of_compat_cmp(s1, s2, l)       strncmp((s1), (s2), (l))
> +#define of_prop_cmp(s1, s2)            strcasecmp((s1), (s2))
> +#define of_node_cmp(s1, s2)            strcmp((s1), (s2))

Ditto here?

> +extern void prom_build_devicetree(void);
> +
> +extern void *prom_early_alloc(unsigned long size);
> +
> +extern char *prom_firstprop(phandle node, char *buf);
> +extern char *prom_nextprop(phandle node, const char *prev, char *buf);
> +extern int prom_getproplen(phandle node, const char *prop);
> +extern int prom_getproperty(phandle node, const char *prop,
> +                            char *buffer, int bufsize);
> +extern phandle prom_getchild(phandle node);
> +extern phandle prom_getsibling(phandle node);
> +
> +#endif /* __KERNEL__ */
> +#endif /* _X86_PROM_OLPC_H */
> diff --git a/arch/x86/include/asm/prom.h b/arch/x86/include/asm/prom.h
> new file mode 100644
> index 0000000..7b561b2
> --- /dev/null
> +++ b/arch/x86/include/asm/prom.h
> @@ -0,0 +1,5 @@
> +#ifdef CONFIG_OLPC_OPENFIRMWARE
> +# include <asm/olpc_prom.h>
> +#else
> +# error "No OFW prom defined for x86!"
> +#endif

Personally, I wouldn't bother with the header file redirection.

> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 0925676..3d7e535 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -105,6 +105,7 @@ scx200-y                    += scx200_32.o
>
>  obj-$(CONFIG_OLPC)             += olpc.o
>  obj-$(CONFIG_OLPC_OPENFIRMWARE)        += olpc_ofw.o
> +obj-$(CONFIG_PROC_DEVICETREE)  += olpc_prom.o
>  obj-$(CONFIG_X86_MRST)         += mrst.o
>
>  microcode-y                            := microcode_core.o
> diff --git a/arch/x86/kernel/olpc_ofw.c b/arch/x86/kernel/olpc_ofw.c
> index 3e13a4b..8838edb 100644
> --- a/arch/x86/kernel/olpc_ofw.c
> +++ b/arch/x86/kernel/olpc_ofw.c
> @@ -6,6 +6,7 @@
>  #include <asm/io.h>
>  #include <asm/pgtable.h>
>  #include <asm/olpc_ofw.h>
> +#include <asm/prom.h>
>
>  /* address of OFW callback interface; will be NULL if OFW isn't found */
>  static int (*olpc_ofw_cif)(int *);
> @@ -103,3 +104,15 @@ void __init olpc_ofw_detect(void)
>                        (unsigned long)olpc_ofw_cif, (-start) >> 20);
>        reserve_top_address(-start);
>  }
> +
> +#ifdef CONFIG_PROC_DEVICETREE
> +static int __init olpc_ofw_build_devicetree(void)
> +{
> +       /* initialize the device-tree that proc uses */
> +       if (olpc_ofw_cif)
> +               prom_build_devicetree();
> +
> +       return 0;
> +}
> +arch_initcall(olpc_ofw_build_devicetree);
> +#endif /* CONFIG_PROC_DEVICETREE */
> diff --git a/arch/x86/kernel/olpc_prom.c b/arch/x86/kernel/olpc_prom.c
> new file mode 100644
> index 0000000..1128f3f
> --- /dev/null
> +++ b/arch/x86/kernel/olpc_prom.c
> @@ -0,0 +1,148 @@
> +/*
> + * olpc_prom.c: OLPC-specific OFW device tree support code.
> + *
> + * 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@davemloft.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/slab.h>
> +#include <linux/of.h>
> +#include <linux/of_pdt.h>
> +#include <asm/olpc_ofw.h>
> +#include <asm/prom.h>
> +
> +phandle prom_getsibling(phandle node)
> +{
> +       const void *args[] = { (void *)node };
> +       void *res[] = { &node };
> +
> +       if (node == -1)
> +               return -1;
> +
> +       if (olpc_ofw("peer", args, res) || node == -1)
> +               return -1;
> +
> +       return node;
> +}
> +
> +phandle prom_getchild(phandle node)
> +{
> +       const void *args[] = { (void *)node };
> +       void *res[] = { &node };
> +
> +       if (node == -1)
> +               return 0;
> +
> +       if (olpc_ofw("child", args, res) || node == -1) {
> +               printk(KERN_ERR "PROM: %s: fetching child failed!\n", __func__);
> +               return 0;
> +       }
> +
> +       return node;
> +}
> +
> +int prom_getproplen(phandle node, const char *prop)
> +{
> +       const void *args[] = { (void *)node, prop };
> +       int len;
> +       void *res[] = { &len };
> +
> +       if (node == -1)
> +               return 0;
> +
> +       if (olpc_ofw("getproplen", args, res)) {
> +               printk(KERN_ERR "PROM: %s: getproplen failed!\n", __func__);
> +               return 0;
> +       }
> +
> +       return len;
> +}
> +
> +int prom_getproperty(phandle node, const char *prop, char *buf,
> +               int bufsize)
> +{
> +       int plen;
> +
> +       plen = prom_getproplen(node, prop);
> +       if (plen > bufsize || plen < 1)
> +               return -1;
> +       else {
> +               const void *args[] = { (void *)node, prop, buf, (void *)plen };
> +               void *res[] = { &plen };
> +
> +               if (olpc_ofw("getprop", args, res)) {
> +                       printk(KERN_ERR "PROM: %s: getprop failed!\n", __func__);
> +                       return -1;
> +               }
> +               //((unsigned char *)buf)[plen] = '\0';
> +       }
> +
> +       return 0;
> +}
> +
> +char *prom_firstprop(phandle node, char *buf)
> +{
> +       buf[0] = '\0';
> +
> +       if (node == -1)
> +               return NULL;
> +
> +       return prom_nextprop(node, "", buf);
> +}
> +
> +char *prom_nextprop(phandle node, const char *prev, char *buf)
> +{
> +       const void *args[] = { (void *)node, prev, buf };
> +       int success;
> +       void *res[] = { &success };
> +
> +       buf[0] = '\0';
> +
> +       if (node == -1)
> +               return NULL;
> +
> +       if (olpc_ofw("nextprop", args, res) || success != 1) {
> +               printk(KERN_ERR "PROM: %s: nextprop failed!\n", __func__);
> +               return NULL;
> +       }
> +
> +       return buf;
> +}
> +
> +void * __init prom_early_alloc(unsigned long size)
> +{
> +       /* unlike SPARC, we don't bother keeping track of prom memory */
> +       return kzalloc(size, GFP_KERNEL);
> +}
> +
> +void __init prom_build_devicetree(void)
> +{
> +       struct device_node **nextp;
> +       phandle root;
> +
> +       root = prom_getsibling(0);
> +       if (root < 0) {
> +               printk(KERN_ERR "PROM: unable to get root node from OFW!\n");
> +               return;
> +       }
> +
> +       allnodes = prom_create_node(root, NULL);
> +       allnodes->full_name = "/";
> +
> +       nextp = &allnodes->allnext;
> +       allnodes->child = prom_build_tree(allnodes,
> +                       prom_getchild(allnodes->phandle), &nextp);
> +}
> diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig
> index 858a859..86f67ce 100644
> --- a/fs/proc/Kconfig
> +++ b/fs/proc/Kconfig
> @@ -41,7 +41,7 @@ config PROC_VMCORE
>
>  config PROC_DEVICETREE
>        bool "Support for device tree in /proc"
> -       depends on PROC_FS && (PPC || MICROBLAZE)
> +       depends on PROC_FS && (PPC || MICROBLAZE || OLPC_OPENFIRMWARE)

This change should no longer be necessary with the way I've modified patch 3/4.

Cheers,
g.