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    SubjectRe: [PATCH] x86: OLPC: add OLPC device-tree support (v3)
    On Wed, 27 Oct 2010, Grant Likely wrote:

    > On Fri, Oct 22, 2010 at 03:58:46PM -0700, Andres Salomon 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.
    > >
    > > v3: rename olpc_prom to olpc_dt
    > > - rework Kconfig entries
    > > - drop devtree build hook from proc, instead adding a call to x86's
    > > paging_init (similarly to how sparc64 does it)
    > > - switch allocation from using slab to alloc_bootmem. this allows
    > > the DT to be built earlier during boot (during setup_arch); the
    > > downside is that there are some 1200 bootmem reservations that are
    > > done during boot. Not ideal..
    > > - add a helper olpc_ofw_is_installed function to test for the
    > > existence and successful detection of OLPC's OFW.
    > >
    > > Signed-off-by: Andres Salomon <dilinger@queued.net>
    >
    > Overall this patch looks fine, but it needs to be acked from the x86
    > maintainers, and I'd like it to have a cycle through linux-next before
    > it gets merged, so that means 2.6.38 because the 2.6.37 merge window
    > has already been open for almost a week.

    Fine with me. That's sufficiently self contained :) So

    Acked-by: Thomas Gleixner <tglx@linutronix.de>


    > The promtree patches have been merged though.
    >
    > Comments below.
    >
    > g.
    >
    > > ---
    > > arch/x86/Kconfig | 6 ++
    > > arch/x86/include/asm/olpc_ofw.h | 9 ++
    > > arch/x86/include/asm/prom.h | 1 +
    > > arch/x86/kernel/Makefile | 1 +
    > > arch/x86/kernel/olpc_dt.c | 165 +++++++++++++++++++++++++++++++++++++++
    > > arch/x86/kernel/olpc_ofw.c | 5 +
    > > arch/x86/mm/init_32.c | 2 +
    > > 7 files changed, 189 insertions(+), 0 deletions(-)
    > > create mode 100644 arch/x86/include/asm/prom.h
    > > create mode 100644 arch/x86/kernel/olpc_dt.c
    > >
    > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
    > > index cea0cd9..1d57e2b 100644
    > > --- a/arch/x86/Kconfig
    > > +++ b/arch/x86/Kconfig
    > > @@ -2069,11 +2069,17 @@ config OLPC_OPENFIRMWARE
    > > bool "Support for OLPC's Open Firmware"
    > > depends on !X86_64 && !X86_PAE
    > > default y if OLPC
    > > + select OF
    > > help
    > > This option adds support for the implementation of Open Firmware
    > > that is used on the OLPC XO-1 Children's Machine.
    > > If unsure, say N here.
    > >
    > > +config OLPC_OPENFIRMWARE_DT
    > > + bool
    > > + default y if OLPC_OPENFIRMWARE && PROC_DEVICETREE
    > > + select OF_PROMTREE
    > > +
    > > endif # X86_32
    > >
    > > config K8_NB
    > > diff --git a/arch/x86/include/asm/olpc_ofw.h b/arch/x86/include/asm/olpc_ofw.h
    > > index 08fde47..a41250e 100644
    > > --- a/arch/x86/include/asm/olpc_ofw.h
    > > +++ b/arch/x86/include/asm/olpc_ofw.h
    > > @@ -8,6 +8,8 @@
    > >
    > > #ifdef CONFIG_OLPC_OPENFIRMWARE
    > >
    > > +extern bool olpc_ofw_is_installed(void);
    > > +
    > > /* run an OFW command by calling into the firmware */
    > > #define olpc_ofw(name, args, res) \
    > > __olpc_ofw((name), ARRAY_SIZE(args), args, ARRAY_SIZE(res), res)
    > > @@ -23,9 +25,16 @@ extern void setup_olpc_ofw_pgd(void);
    > >
    > > #else /* !CONFIG_OLPC_OPENFIRMWARE */
    > >
    > > +static inline bool olpc_ofw_is_installed(void) { return false; }
    > > static inline void olpc_ofw_detect(void) { }
    > > static inline void setup_olpc_ofw_pgd(void) { }
    > >
    > > #endif /* !CONFIG_OLPC_OPENFIRMWARE */
    > >
    > > +#ifdef CONFIG_OLPC_OPENFIRMWARE_DT
    > > +extern void olpc_dt_build_devicetree(void);
    > > +#else
    > > +static inline void olpc_dt_build_devicetree(void) { }
    > > +#endif /* CONFIG_OLPC_OPENFIRMWARE_DT */
    > > +
    > > #endif /* _ASM_X86_OLPC_OFW_H */
    > > diff --git a/arch/x86/include/asm/prom.h b/arch/x86/include/asm/prom.h
    > > new file mode 100644
    > > index 0000000..b4ec95f
    > > --- /dev/null
    > > +++ b/arch/x86/include/asm/prom.h
    > > @@ -0,0 +1 @@
    > > +/* dummy prom.h; here to make linux/of.h's #includes happy */
    > > diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
    > > index fedf32a..519539a 100644
    > > --- a/arch/x86/kernel/Makefile
    > > +++ b/arch/x86/kernel/Makefile
    > > @@ -107,6 +107,7 @@ scx200-y += scx200_32.o
    > >
    > > obj-$(CONFIG_OLPC) += olpc.o
    > > obj-$(CONFIG_OLPC_OPENFIRMWARE) += olpc_ofw.o
    > > +obj-$(CONFIG_OLPC_OPENFIRMWARE_DT) += olpc_dt.o
    >
    > olpc_ofw_dt.o perhaps?
    >
    > > obj-$(CONFIG_X86_MRST) += mrst.o
    > >
    > > microcode-y := microcode_core.o
    > > diff --git a/arch/x86/kernel/olpc_dt.c b/arch/x86/kernel/olpc_dt.c
    > > new file mode 100644
    > > index 0000000..f660a11
    > > --- /dev/null
    > > +++ b/arch/x86/kernel/olpc_dt.c
    > > @@ -0,0 +1,165 @@
    > > +/*
    > > + * olpc_dt.c: OLPC-specific OFW device tree support code.
    >
    > Nit: I personally prefer not to see the file name encoded in the
    > header block.
    >
    > > + *
    > > + * 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
    > > + * Adapted for x86/OLPC by Andres Salomon <dilinger@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/bootmem.h>
    > > +#include <linux/of.h>
    > > +#include <linux/of_pdt.h>
    > > +#include <asm/olpc_ofw.h>
    > > +
    > > +static phandle __init olpc_dt_getsibling(phandle node)
    > > +{
    > > + const void *args[] = { (void *)node };
    > > + void *res[] = { &node };
    > > +
    > > + if (node == -1)
    > > + return 0;
    >
    > phandle is a u32, so testing against a negative value is not sane.
    >
    > > +
    > > + if (olpc_ofw("peer", args, res) || node == -1)
    > > + return 0;
    > > +
    > > + return node;
    > > +}
    > > +
    > > +static phandle __init olpc_dt_getchild(phandle node)
    > > +{
    > > + const void *args[] = { (void *)node };
    > > + void *res[] = { &node };
    > > +
    > > + if (node == -1)
    > > + return 0;
    > > +
    > > + if (olpc_ofw("child", args, res) || node == -1) {
    > > + pr_err("PROM: %s: fetching child failed!\n", __func__);
    > > + return 0;
    > > + }
    > > +
    > > + return node;
    > > +}
    > > +
    > > +static int __init olpc_dt_getproplen(phandle node, const char *prop)
    > > +{
    > > + const void *args[] = { (void *)node, prop };
    > > + int len;
    > > + void *res[] = { &len };
    > > +
    > > + if (node == -1)
    > > + return -1;
    > > +
    > > + if (olpc_ofw("getproplen", args, res)) {
    > > + pr_err("PROM: %s: getproplen failed!\n", __func__);
    > > + return -1;
    > > + }
    > > +
    > > + return len;
    > > +}
    > > +
    > > +static int __init olpc_dt_getproperty(phandle node, const char *prop,
    > > + char *buf, int bufsize)
    > > +{
    > > + int plen;
    > > +
    > > + plen = olpc_dt_getproplen(node, prop);
    > > + if (plen > bufsize || plen < 1)
    > > + return -1;
    > > + else {
    >
    > Nit: If there are braces on the else clause, then please use them on
    > the if() clause also.
    >
    > > + const void *args[] = { (void *)node, prop, buf, (void *)plen };
    > > + void *res[] = { &plen };
    > > +
    > > + if (olpc_ofw("getprop", args, res)) {
    > > + pr_err("PROM: %s: getprop failed!\n", __func__);
    > > + return -1;
    > > + }
    > > + }
    > > +
    > > + return plen;
    > > +}
    > > +
    > > +static int __init olpc_dt_nextprop(phandle node, char *prev, char *buf)
    > > +{
    > > + const void *args[] = { (void *)node, prev, buf };
    >
    > This looks wrong. It does not look sane to cast node as a pointer
    > (which won't be the same size on x86_64), and then recast it to an int
    > inside __olpc_ofw(). Do you know why the api is implemented in this
    > way?
    >
    > > + int success;
    > > + void *res[] = { &success };
    > > +
    > > + buf[0] = '\0';
    > > +
    > > + if (node == -1)
    > > + return -1;
    > > +
    > > + if (olpc_ofw("nextprop", args, res) || success != 1)
    > > + return -1;
    > > +
    > > + return 0;
    > > +}
    > > +
    > > +static int __init olpc_dt_pkg2path(phandle node, char *buf,
    > > + const int buflen, int *len)
    > > +{
    > > + const void *args[] = { (void *)node, buf, (void *)buflen };
    > > + void *res[] = { len };
    > > +
    > > + if (node == -1)
    > > + return -1;
    > > +
    > > + if (olpc_ofw("package-to-path", args, res) || *len < 1)
    > > + return -1;
    > > +
    > > + return 0;
    > > +}
    > > +
    > > +static unsigned int prom_early_allocated __initdata;
    > > +
    > > +void * __init prom_early_alloc(unsigned long size)
    > > +{
    > > + void *res;
    > > +
    > > + res = alloc_bootmem(size);
    > > + if (res)
    > > + memset(res, 0, size);
    > > +
    > > + prom_early_allocated += size;
    > > +
    > > + return res;
    > > +}
    > > +
    > > +static struct of_pdt_ops prom_olpc_ops __initdata = {
    > > + .nextprop = olpc_dt_nextprop,
    > > + .getproplen = olpc_dt_getproplen,
    > > + .getproperty = olpc_dt_getproperty,
    > > + .getchild = olpc_dt_getchild,
    > > + .getsibling = olpc_dt_getsibling,
    > > + .pkg2path = olpc_dt_pkg2path,
    > > +};
    > > +
    > > +void __init olpc_dt_build_devicetree(void)
    > > +{
    > > + phandle root;
    > > +
    > > + if (!olpc_ofw_is_installed())
    > > + return;
    > > +
    > > + root = olpc_dt_getsibling(0);
    > > + if (root < 0) {
    > > + pr_err("PROM: unable to get root node from OFW!\n");
    > > + return;
    > > + }
    > > + of_pdt_build_devicetree(root, &prom_olpc_ops);
    > > +
    > > + pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
    > > + prom_early_allocated);
    > > +}
    > > diff --git a/arch/x86/kernel/olpc_ofw.c b/arch/x86/kernel/olpc_ofw.c
    > > index 3218aa7..2176048 100644
    > > --- a/arch/x86/kernel/olpc_ofw.c
    > > +++ b/arch/x86/kernel/olpc_ofw.c
    > > @@ -104,3 +104,8 @@ void __init olpc_ofw_detect(void)
    > > (unsigned long)olpc_ofw_cif, (-start) >> 20);
    > > reserve_top_address(-start);
    > > }
    > > +
    > > +bool __init olpc_ofw_is_installed(void)
    > > +{
    > > + return olpc_ofw_cif != NULL;
    > > +}
    > > diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
    > > index bca7909..41bf85f 100644
    > > --- a/arch/x86/mm/init_32.c
    > > +++ b/arch/x86/mm/init_32.c
    > > @@ -44,6 +44,7 @@
    > > #include <asm/bugs.h>
    > > #include <asm/tlb.h>
    > > #include <asm/tlbflush.h>
    > > +#include <asm/olpc_ofw.h>
    > > #include <asm/pgalloc.h>
    > > #include <asm/sections.h>
    > > #include <asm/paravirt.h>
    > > @@ -833,6 +834,7 @@ void __init paging_init(void)
    > > /*
    > > * NOTE: at this point the bootmem allocator is fully available.
    > > */
    > > + olpc_dt_build_devicetree();
    > > sparse_init();
    > > zone_sizes_init();
    > > }
    > > --
    > > 1.5.6.5
    > >
    >


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