On Wed, Feb 05, 2014 at 08:15:46PM +0100, Stephen Warren wrote:
> On 01/28/2014 04:36 PM, Peter De Schrijver wrote:
> > Implement fuse driver for Tegra20, Tegra30, Tegra114 and Tegra124.
>
> I assume most of this code is simply cut/paste from the existing code in
> arch/arm/mach-tegra/? If so, "git format-patch -C" would have been
> useful to highlight what changed when duplicating the files.
>
It also has been rewritten slightly. Also the Tegra124 speedo file is new.
> > diff --git a/Documentation/ABI/testing/sysfs-driver-tegra-fuse b/Documentation/ABI/testing/sysfs-driver-tegra-fuse
> > +What: /sys/devices/*/<our-device>/fuse
> > +Date: December 2013
> > +Contact: Peter De Schrijver <pdeschrijver@xxxxxxxxxx>
> > +Description: read-only access to the efuses on Tegra20, Tegra30, Tegra114
> > + and Tegra124 SoC's from NVIDIA. The efuses contain write once
> > + data programmed at the factory.
> > +Users: any user space application which wants to read the efuses on
> > + Tegra SoC's
>
> Surely this file should describe the format of the file, since that's
> part of the ABI too, right?
>
Part of the fuse data is ODM defined so possibly board specific.
> > diff --git a/drivers/misc/fuse/tegra/fuse-tegra20.c b/drivers/misc/fuse/tegra/fuse-tegra20.c
>
> > +static int tegra20_fuse_probe(struct platform_device *pdev)
> ...
> > + sku_info.revision = tegra_revision;
> > + tegra20_init_speedo_data(&sku_info, &pdev->dev);
> ...
> > +}
> > +
> > +static struct platform_driver tegra20_fuse_driver = {
> > + .probe = tegra20_fuse_probe,
> > + .driver = {
> > + .name = "tegra20_fuse",
> > + .owner = THIS_MODULE,
> > + .of_match_table = tegra20_fuse_of_match,
> > + }
> > +};
> > +
> > +static int __init tegra20_fuse_init(void)
> > +{
> > + return platform_driver_register(&tegra20_fuse_driver);
> > +}
> > +postcore_initcall(tegra20_fuse_init);
>
> That call to tegra20_init_speedo_data() now happens much later in boot.
> Are you sure there's nothing that relies on data it sets up between when
> tegra_fuse_init() is called (which is where it happens before this
> series), and the somewhat arbitrary later time when this driver probes?
>
Will check.
> > diff --git a/drivers/misc/fuse/tegra/fuse-tegra30.c b/drivers/misc/fuse/tegra/fuse-tegra30.c
>
> > +postcore_initcall(tegra30_fuse_init);
> > +
>
> There's a blank line at the end of the file. I thought checkpatch warned
> about this? But actually it doesn't seem to at least in -f mode.
>
> > diff --git a/drivers/misc/fuse/tegra/fuse.h b/drivers/misc/fuse/tegra/fuse.h
>
> > +struct tegra_sku_info {
> > + int sku_id;
> > + int cpu_process_id;
> > + int cpu_speedo_id;
> > + int cpu_speedo_value;
> > + int cpu_iddq_value;
> > + int core_process_id;
> > + int soc_speedo_id;
> > + int gpu_speedo_id;
> > + int gpu_process_id;
> > + int gpu_speedo_value;
> > + enum tegra_revision revision;
> > +};
>
> The only use of this appears to be to pass to tegra_fuse_create_sysfs()
> which prints out the fields. Will there be more users in the future?
> Otherwise, I'd be tempted to just print it out outside/before-calling
> tegra_fuse_create_sysfs().
>
> That said, I wonder if these values could/should be exposed in the sysfs
> file to make it easier to interpret the fuses?
>
That could be done I think...
> > diff --git a/drivers/misc/fuse/tegra/tegra114_speedo.c b/drivers/misc/fuse/tegra/tegra114_speedo.c
>
> It might be nice to make these filenames consistent with the others,
> e.g. fuse-speedo-tegraNNN.c/speedo-tegraNNN.c, or wrap them into
> fuse-tegraNNN.c?
>
I expect 1 speedo file per new SoC, but at least every SoC since Tegra30 has
used the same way of reading the fuse data. Hence I think it's better to
keep them separate.
> > diff --git a/drivers/misc/fuse/tegra/tegra30_speedo.c b/drivers/misc/fuse/tegra/tegra30_speedo.c
>
> > +#define FUSE_SPEEDO_CALIB_0 0x14
> > +#define FUSE_PACKAGE_INFO 0XFC
> > +#define FUSE_TEST_PROG_VER 0X28
>
> In arch/arm/mach-tegra/tegra30_speedo.c, those values are different:
>
> #define FUSE_SPEEDO_CALIB_0 0x114
> #define FUSE_PACKAGE_INFO 0X1FC
> #define FUSE_TEST_PROG_VER 0X128
>
> Was this change intentional? Perhaps it should be in a separate patch to
> highlight the change, if it's an intentional bug-fix?
This is intentional. The old files used the offset from the fuse IP block base
address. The new files use the offset in the fuse array.
Cheers,
Peter.
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