[RFC 5/8] lib: add small API for handling register snapshots

[Rob Clark]

On Fri, May 28, 2021 at 5:25 PM Dmitry Baryshkov
<dmitry.baryshkov at linaro.org> wrote:
>
> Add small API covering lists of register dumps. Currently this is a part
> of MSM DRM driver, but is extracted as it might be usefull to other
> drivers too.
>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> ---
>  include/linux/dump_state.h | 78 ++++++++++++++++++++++++++++++++++++++
>  lib/Kconfig                |  3 ++
>  lib/Makefile               |  1 +
>  lib/dump_state.c           | 51 +++++++++++++++++++++++++
>  4 files changed, 133 insertions(+)
>  create mode 100644 include/linux/dump_state.h
>  create mode 100644 lib/dump_state.c
>
[snip]
> diff --git a/lib/dump_state.c b/lib/dump_state.c
> new file mode 100644
> index 000000000000..58d88be65c0a
> --- /dev/null
> +++ b/lib/dump_state.c
> @@ -0,0 +1,51 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2020-2021, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2021, Linaro Ltd
> + */
> +
> +#include <linux/dump_state.h>
> +#include <linux/slab.h>
> +
> +void dump_state_free_blocks(struct dump_state *state)
> +{
> +       struct dump_state_block *block, *tmp;
> +
> +       list_for_each_entry_safe(block, tmp, &state->blocks, node) {
> +               list_del(&block->node);
> +               kfree(block);
> +       }
> +}
> +EXPORT_SYMBOL(dump_state_free_blocks);

nit, perhaps EXPORT_SYMBOL_GPL()?

BR,
-R

> +
> +struct dump_state_block *dump_state_allocate_block_va(void __iomem *base_addr, size_t len, gfp_t gfp, const char *fmt, va_list args)
> +{
> +       struct dump_state_block *block = kzalloc(sizeof(*block) + len, gfp);
> +
> +       if (!block)
> +               return ERR_PTR(-ENOMEM);
> +
> +       vsnprintf(block->name, sizeof(block->name), fmt, args);
> +
> +       INIT_LIST_HEAD(&block->node);
> +       block->size = len;
> +       block->base_addr = base_addr;
> +
> +       return block;
> +}
> +EXPORT_SYMBOL(dump_state_allocate_block);
> +
> +struct dump_state_block *dump_state_allocate_block(void __iomem *base_addr, size_t len, gfp_t gfp, const char *fmt, ...)
> +{
> +       struct dump_state_block *block;
> +       va_list va;
> +
> +       va_start(va, fmt);
> +
> +       block = dump_state_allocate_block_va(base_addr, len, gfp, fmt, va);
> +
> +       va_end(va);
> +
> +       return block;
> +}
> +EXPORT_SYMBOL(dump_state_allocate_block_va);
> --
> 2.30.2
>