[PATCH RESEND v2] ARM: dt: Use the 'model' field for printing the hardware revision

[PATCH RESEND v2] ARM: dt: Use the 'model' field for printing the hardware revision

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam@freescale.com>

When booting a device tree kernel, we get the following output from 
'cat /proc/cpuinfo': 

$ cat /proc/cpuinfo 
processor       : 0
model name      : ARMv7 Processor rev 5 (v7l)
BogoMIPS        : 531.66
Features        : swp half thumb fastmult vfp edsp neon vfpv3 tls 
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x2
CPU part        : 0xc08
CPU revision    : 5

Hardware        : Freescale i.MX51 (Device Tree Support)
Revision        : 0000
Serial          : 0000000000000000

The Hardware line does not really describe the hardware type, as it is reading
the information from the dt 'machine' field.

In the dt case, read the 'model' field instead, so that we can have a better
description output as follows:

Hardware        : Freescale i.MX51 Babbage Board

The hardware output string is unchanged for the non-dt kernel case.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
Changes since v1:
- Fix typo in 'architecture'
 arch/arm/include/asm/mach/arch.h |  1 +
 arch/arm/kernel/devtree.c        | 15 ++++++++-------
 arch/arm/kernel/setup.c          |  7 ++++++-
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h
index 308ad7d..113d4af 100644
--- a/arch/arm/include/asm/mach/arch.h
+++ b/arch/arm/include/asm/mach/arch.h
@@ -23,6 +23,7 @@ struct smp_operations;
 struct machine_desc {
 	unsigned int		nr;		/* architecture number	*/
 	const char		*name;		/* architecture name	*/
+	const char		*model;		/* architecture model */
 	unsigned long		atag_offset;	/* tagged list (relative) */
 	const char *const 	*dt_compat;	/* array of device tree
 						 * 'compatible' strings	*/
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index 5af04f6..90d541a 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -178,7 +178,6 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
 	struct machine_desc *mdesc, *mdesc_best = NULL;
 	unsigned int score, mdesc_score = ~1;
 	unsigned long dt_root;
-	const char *model;
 
 #ifdef CONFIG_ARCH_MULTIPLATFORM
 	DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
@@ -224,12 +223,14 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
 		dump_machine_table(); /* does not return */
 	}
 
-	model = of_get_flat_dt_prop(dt_root, "model", NULL);
-	if (!model)
-		model = of_get_flat_dt_prop(dt_root, "compatible", NULL);
-	if (!model)
-		model = "<unknown>";
-	pr_info("Machine: %s, model: %s\n", mdesc_best->name, model);
+	mdesc_best->model = of_get_flat_dt_prop(dt_root, "model", NULL);
+	if (!mdesc_best->model)
+		mdesc_best->model = of_get_flat_dt_prop(dt_root, "compatible",
+							NULL);
+	if (!mdesc_best->model)
+		mdesc_best->model = "<unknown>";
+	pr_info("Machine: %s, model: %s\n", mdesc_best->name,
+		mdesc_best->model);
 
 	/* Retrieve various information from the /chosen node */
 	of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 79e8d2f..d22f24b 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -137,6 +137,7 @@ EXPORT_SYMBOL(elf_platform);
 
 static const char *cpu_name;
 static const char *machine_name;
+static const char *model_name;
 static char __initdata cmd_line[COMMAND_LINE_SIZE];
 struct machine_desc *machine_desc __initdata;
 
@@ -786,6 +787,7 @@ void __init setup_arch(char **cmdline_p)
 		mdesc = setup_machine_tags(__atags_pointer, __machine_arch_type);
 	machine_desc = mdesc;
 	machine_name = mdesc->name;
+	model_name = mdesc->model;
 
 	setup_dma_zone(mdesc);
 
@@ -950,7 +952,10 @@ static int c_show(struct seq_file *m, void *v)
 		seq_printf(m, "CPU revision\t: %d\n\n", cpuid & 15);
 	}
 
-	seq_printf(m, "Hardware\t: %s\n", machine_name);
+	if (model_name)
+		seq_printf(m, "Hardware\t: %s\n", model_name);
+	else
+		seq_printf(m, "Hardware\t: %s\n", machine_name);
 	seq_printf(m, "Revision\t: %04x\n", system_rev);
 	seq_printf(m, "Serial\t\t: %08x%08x\n",
 		   system_serial_high, system_serial_low);
-- 
1.8.1.2

[PATCH RESEND v2] ARM: dt: Use the 'model' field for printing the hardware revision

[Russell King - ARM Linux]

On Fri, Jul 26, 2013 at 10:19:44AM -0300, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@freescale.com>
> 
> When booting a device tree kernel, we get the following output from 
> 'cat /proc/cpuinfo': 
> 
> $ cat /proc/cpuinfo 
> processor       : 0
> model name      : ARMv7 Processor rev 5 (v7l)
> BogoMIPS        : 531.66
> Features        : swp half thumb fastmult vfp edsp neon vfpv3 tls 
> CPU implementer : 0x41
> CPU architecture: 7
> CPU variant     : 0x2
> CPU part        : 0xc08
> CPU revision    : 5
> 
> Hardware        : Freescale i.MX51 (Device Tree Support)
> Revision        : 0000
> Serial          : 0000000000000000
> 
> The Hardware line does not really describe the hardware type, as it is reading
> the information from the dt 'machine' field.
> 
> In the dt case, read the 'model' field instead, so that we can have a better
> description output as follows:
> 
> Hardware        : Freescale i.MX51 Babbage Board
> 
> The hardware output string is unchanged for the non-dt kernel case.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

While I can see the advantage of preserving old ways to do things, that's
not always the best option.

If userspace wants to get at the DT information about a platform, we already
have ways that can happen already - we export the DT stuff so that kexec's
tools can get at it.

And... as the long term goal is to get rid of the individual machine_type
structures for DT, there's no point introducing the new "model" field in
that struct.

And no, you're not supposed to write to mdesc structures.  Thanks for
being the one to point out that they aren't const, I'll make them so now.

[PATCH RESEND v2] ARM: dt: Use the 'model' field for printing the hardware revision

[Rob Herring]

On Fri, Jul 26, 2013 at 8:19 AM, Fabio Estevam <festevam@gmail.com> wrote:
> From: Fabio Estevam <fabio.estevam@freescale.com>
>
> When booting a device tree kernel, we get the following output from
> 'cat /proc/cpuinfo':
>
> $ cat /proc/cpuinfo
> processor       : 0
> model name      : ARMv7 Processor rev 5 (v7l)
> BogoMIPS        : 531.66
> Features        : swp half thumb fastmult vfp edsp neon vfpv3 tls
> CPU implementer : 0x41
> CPU architecture: 7
> CPU variant     : 0x2
> CPU part        : 0xc08
> CPU revision    : 5
>
> Hardware        : Freescale i.MX51 (Device Tree Support)
> Revision        : 0000
> Serial          : 0000000000000000
>
> The Hardware line does not really describe the hardware type, as it is reading
> the information from the dt 'machine' field.
>
> In the dt case, read the 'model' field instead, so that we can have a better
> description output as follows:
>
> Hardware        : Freescale i.MX51 Babbage Board
>
> The hardware output string is unchanged for the non-dt kernel case.
>
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
> Changes since v1:
> - Fix typo in 'architecture'
>  arch/arm/include/asm/mach/arch.h |  1 +
>  arch/arm/kernel/devtree.c        | 15 ++++++++-------
>  arch/arm/kernel/setup.c          |  7 ++++++-
>  3 files changed, 15 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h
> index 308ad7d..113d4af 100644
> --- a/arch/arm/include/asm/mach/arch.h
> +++ b/arch/arm/include/asm/mach/arch.h
> @@ -23,6 +23,7 @@ struct smp_operations;
>  struct machine_desc {
>         unsigned int            nr;             /* architecture number  */
>         const char              *name;          /* architecture name    */
> +       const char              *model;         /* architecture model */

As Russell said, we want to get rid of machine_desc at some point. So
I think a better approach is to remove the .name field (i.e. make it
NULL for now) for the DT case.

>         unsigned long           atag_offset;    /* tagged list (relative) */
>         const char *const       *dt_compat;     /* array of device tree
>                                                  * 'compatible' strings */
> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
> index 5af04f6..90d541a 100644
> --- a/arch/arm/kernel/devtree.c
> +++ b/arch/arm/kernel/devtree.c
> @@ -178,7 +178,6 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
>         struct machine_desc *mdesc, *mdesc_best = NULL;
>         unsigned int score, mdesc_score = ~1;
>         unsigned long dt_root;
> -       const char *model;
>
>  #ifdef CONFIG_ARCH_MULTIPLATFORM
>         DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
> @@ -224,12 +223,14 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
>                 dump_machine_table(); /* does not return */
>         }
>
> -       model = of_get_flat_dt_prop(dt_root, "model", NULL);
> -       if (!model)
> -               model = of_get_flat_dt_prop(dt_root, "compatible", NULL);
> -       if (!model)
> -               model = "<unknown>";
> -       pr_info("Machine: %s, model: %s\n", mdesc_best->name, model);
> +       mdesc_best->model = of_get_flat_dt_prop(dt_root, "model", NULL);

This won't work with Russell's constifying of machine_desc patch.

Rob