[PATCH 2/6] ARM: introduce machine description
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Mon Dec 2 06:04:52 EST 2013
On 10:01 Mon 02 Dec , Sascha Hauer wrote:
> On Thu, Nov 28, 2013 at 07:06:43PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > This will allow to do not check in each board which machine we are running
> > from. This work on DT & non-DT board.
> >
> > If only one board is enable autoselect it
> >
> > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> > ---
> > arch/arm/cpu/Makefile | 2 +-
> > arch/arm/cpu/dtb.c | 8 +-
> > arch/arm/cpu/machine.c | 188 +++++++++++++++++++++++++++++++++++++
> > arch/arm/include/asm/barebox-arm.h | 8 ++
> > arch/arm/include/asm/mach/arch.h | 68 ++++++++++++++
> > arch/arm/lib/barebox.lds.S | 6 ++
> > 6 files changed, 277 insertions(+), 3 deletions(-)
> > create mode 100644 arch/arm/cpu/machine.c
> > create mode 100644 arch/arm/include/asm/mach/arch.h
> >
> > diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile
> > index aba201b..78532da 100644
> > --- a/arch/arm/cpu/Makefile
> > +++ b/arch/arm/cpu/Makefile
> > @@ -1,7 +1,7 @@
> > obj-y += cpu.o
> > obj-$(CONFIG_ARM_EXCEPTIONS) += exceptions.o
> > obj-$(CONFIG_ARM_EXCEPTIONS) += interrupts.o
> > -obj-y += start.o setupc.o
> > +obj-y += machine.o start.o setupc.o
> >
> > #
> > # Any variants can be called as start-armxyz.S
> > diff --git a/arch/arm/cpu/dtb.c b/arch/arm/cpu/dtb.c
> > index a5881dd..ee7006e 100644
> > --- a/arch/arm/cpu/dtb.c
> > +++ b/arch/arm/cpu/dtb.c
> > @@ -18,10 +18,11 @@
> > #include <init.h>
> > #include <of.h>
> > #include <asm/barebox-arm.h>
> > +#include <asm/mach/arch.h>
> >
> > extern char __dtb_start[];
> >
> > -static int of_arm_init(void)
> > +int of_arm_init(void)
> > {
> > struct device_node *root;
> > void *fdt;
> > @@ -48,6 +49,10 @@ static int of_arm_init(void)
> > }
> >
> > root = of_unflatten_dtb(NULL, fdt);
> > +
> > + if (arm_set_dt_machine(NULL))
> > + pr_debug("No compatible machine found\n");
>
> Why call this with NULL and not the compatible string found in the just
> unflattened dt?
if NULL the code check for the compatible node
otherwise for a specific compatible passs as arg
>
> > +
> > if (root) {
> > of_set_root_node(root);
> > if (IS_ENABLED(CONFIG_OFDEVICE))
> > @@ -56,4 +61,3 @@ static int of_arm_init(void)
> >
> > return 0;
> > }
> > -core_initcall(of_arm_init);
> > diff --git a/arch/arm/cpu/machine.c b/arch/arm/cpu/machine.c
> > new file mode 100644
> > index 0000000..ad0d8cb
> > --- /dev/null
> > +++ b/arch/arm/cpu/machine.c
> > @@ -0,0 +1,188 @@
> > +/*
> > + * Copyright (C) 2013 Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> > + *
> > + * Under GPLv2 Only
> > + */
> > +
> > +#include <common.h>
> > +#include <asm/mach/arch.h>
> > +#include <asm/barebox-arm.h>
> > +#include <asm/armlinux.h>
> > +#include <generated/mach-types.h>
> > +#include <init.h>
> > +#include <string.h>
> > +#include <debug_ll.h>
> > +
> > +const struct machine_desc *machine_desc;
> > +unsigned int __machine_arch_type = ~0;
> > +
> > +int arm_set_machine(const unsigned int type)
> > +{
> > + const struct machine_desc *m;
> > +
> > + puts_ll("type ");
> > + puthex_ll(type);
> > + puts_ll("\n");
> > +
> > + if (type == ~0)
> > + return -ENOENT;
> > +
> > + for_each_machine_desc(m) {
> > + puts_ll("machine ");
> > + if (m->name)
> > + puts_ll(m->name);
> > + puts_ll("\n");
> > + if (m->nr == type) {
> > + machine_desc = (const struct machine_desc *)m;
> > + __machine_arch_type = type;
> > + armlinux_set_architecture(__machine_arch_type);
> > + return 0;
> > + }
> > + }
> > +
> > + return -ENOENT;
> > +}
> > +
> > +int is_dt_compatible(const struct machine_desc *m, const char* dt_compat)
> > +{
> > + const char *const *dtc = m->dt_compat;
> > +
> > + while (dtc) {
> > + const char *s = *dtc;
> > + if (dt_compat && !of_compat_cmp(s, dt_compat, strlen(dt_compat)))
> > + return 1;
> > + else if (of_machine_is_compatible(s))
> > + return 1;
> > + dtc++;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +int arm_set_dt_machine(const char* dt_compat)
>
> I don't really understand how this function behaves. It should set the
> machine desc based on dt_compat, but seems to fall back to some other
> mechanism when dt_compat is NULL. Looking at it this function is only
simple 2 case
1 check the compatible node
1 check a specific comp if pas as arg
> called with NULL argument in your code, so it seems like it depends on
> of_machine_is_compatible(), but this can only return something valid
> when the root_node has been set. You call arm_set_dt_machine() before
> of_set_root_node() so this can't work.
>
> Matching a machine_desc to a devicetree is more complicated. You can't
> return the first match, but instead have to find the best match. If you
> have multiple i.MX6 machines, then all will match to fsl,imx6. You have
> to find the correct board though.
no they will have their own compatible in the DT_MACHINE_DESC
so fsl,imx6 execpt if all the board use the same c board file
as we have on the kernel for at91
>
> If you don't have a dt machine to test this on atm I think it's better
> if you just drop dt support from this patchset.
I test the function and use it on some at91 board
and it does work
>
> Sascha
>
> --
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