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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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