Re: [PATCH v8 01/16] clk: generalize devm_clk_get() a bit

Jon Hunter
2022-06-21T19:57:26Z

Hi Uwe,

On 14/03/2022 14:16, Uwe Kleine-König wrote:
> Allow to add an exit hook to devm managed clocks. Also use
> clk_get_optional() in devm_clk_get_optional instead of open coding it.
> The generalisation will be used in the next commit to add some more
> devm_clk helpers.
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Alexandru Ardelean <aardelean@deviqon.com>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
> drivers/clk/clk-devres.c | 67 ++++++++++++++++++++++++++++++----------
> 1 file changed, 50 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
> index f9d5b7334341..fb7761888b30 100644
> --- a/drivers/clk/clk-devres.c
> +++ b/drivers/clk/clk-devres.c
> @@ -4,39 +4,72 @@
> #include <linux/export.h>
> #include <linux/gfp.h>
>
> +struct devm_clk_state {
> + struct clk *clk;
> + void (*exit)(struct clk *clk);
> +};
> +
> static void devm_clk_release(struct device *dev, void *res)
> {
> - clk_put(*(struct clk **)res);
> + struct devm_clk_state *state = *(struct devm_clk_state **)res;
> +
> + if (state->exit)
> + state->exit(state->clk);
> +
> + clk_put(state->clk);
> }
>
> -struct clk *devm_clk_get(struct device *dev, const char *id)
> +static struct clk *__devm_clk_get(struct device *dev, const char *id,
> + struct clk *(*get)(struct device *dev, const char *id),
> + int (*init)(struct clk *clk),
> + void (*exit)(struct clk *clk))
> {
> - struct clk **ptr, *clk;
> + struct devm_clk_state *state;
> + struct clk *clk;
> + int ret;
>
> - ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
> - if (!ptr)
> + state = devres_alloc(devm_clk_release, sizeof(*state), GFP_KERNEL);
> + if (!state)
> return ERR_PTR(-ENOMEM);
>
> - clk = clk_get(dev, id);
> - if (!IS_ERR(clk)) {
> - *ptr = clk;
> - devres_add(dev, ptr);
> - } else {
> - devres_free(ptr);
> + clk = get(dev, id);
> + if (IS_ERR(clk)) {
> + ret = PTR_ERR(clk);
> + goto err_clk_get;
> }
>
> + if (init) {
> + ret = init(clk);
> + if (ret)
> + goto err_clk_init;
> + }
> +
> + state->clk = clk;
> + state->exit = exit;
> +
> + devres_add(dev, state);
> +
> return clk;
> +
> +err_clk_init:
> +
> + clk_put(clk);
> +err_clk_get:
> +
> + devres_free(state);
> + return ERR_PTR(ret);
> }
> -EXPORT_SYMBOL(devm_clk_get);
>
> -struct clk *devm_clk_get_optional(struct device *dev, const char *id)
> +struct clk *devm_clk_get(struct device *dev, const char *id)
> {
> - struct clk *clk = devm_clk_get(dev, id);
> + return __devm_clk_get(dev, id, clk_get, NULL, NULL);
>
> - if (clk == ERR_PTR(-ENOENT))
> - return NULL;
> +}
> +EXPORT_SYMBOL(devm_clk_get);
>
> - return clk;
> +struct clk *devm_clk_get_optional(struct device *dev, const char *id)
> +{
> + return __devm_clk_get(dev, id, clk_get_optional, NULL, NULL);
> }
> EXPORT_SYMBOL(devm_clk_get_optional);
>

Some of our Tegra boards are not booting with the current -next and
bisect is pointing to this commit. Looking at the boot log I am
seeing the following panic ...

[ 2.097048] 8<--- cut here ---
[ 2.097053] Unable to handle kernel paging request at virtual address c216c810
[ 2.097060] [c216c810] *pgd=0201141e(bad)
[ 2.097079] Internal error: Oops: 8000000d [#1] SMP ARM
[ 2.097088] Modules linked in:
[ 2.097097] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc3-next-20220621-g34d1d36073ea #1
[ 2.097107] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
[ 2.097113] PC is at 0xc216c810
[ 2.097123] LR is at devm_clk_release+0x18/0x24
[ 2.097150] pc : [<c216c810>] lr : [<c088cb04>] psr: a0000013
[ 2.097155] sp : f080dde8 ip : 000006cf fp : c18d4854
[ 2.097161] r10: c1501850 r9 : c1a04d10 r8 : c1c4efa0
[ 2.097166] r7 : c216c810 r6 : f080de1c r5 : c2737680 r4 : c26a9680
[ 2.097172] r3 : c216c810 r2 : 00000000 r1 : c2737840 r0 : c2082840
[ 2.097179] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
[ 2.097187] Control: 10c5387d Table: 0020404a DAC: 00000051
[ 2.097191] Register r0 information: slab kmalloc-192 start c2082840 pointer offset 0 size 192
[ 2.097216] Register r1 information: slab kmalloc-128 start c2737800 pointer offset 64 size 128
[ 2.097236] Register r2 information: NULL pointer
[ 2.097244] Register r3 information: slab kmalloc-1k start c216c800 pointer offset 16 size 1024
[ 2.097263] Register r4 information: slab kmalloc-64 start c26a9680 pointer offset 0 size 64
[ 2.097282] Register r5 information: slab kmalloc-128 start c2737680 pointer offset 0 size 128
[ 2.097301] Register r6 information: 2-page vmalloc region starting at 0xf080c000 allocated at kernel_clone+0xb4/0x3e8
[ 2.097321] Register r7 information: slab kmalloc-1k start c216c800 pointer offset 16 size 1024
[ 2.097341] Register r8 information: non-slab/vmalloc memory
[ 2.097348] Register r9 information: non-slab/vmalloc memory
[ 2.097355] Register r10 information: non-slab/vmalloc memory
[ 2.097362] Register r11 information: non-slab/vmalloc memory
[ 2.097369] Register r12 information: non-paged memory
[ 2.097375] Process swapper/0 (pid: 1, stack limit = 0x(ptrval))
[ 2.097384] Stack: (0xf080dde8 to 0xf080e000)
[ 2.097394] dde0: c2737800 c0a72d38 c18d4854 c0530490 c216c810 f080de1c
[ 2.097404] de00: c2120000 00000005 c216c9c0 80000013 0000017e c0a73d68 00000008 c2629e00
[ 2.097413] de20: c2737880 5640e141 c216c810 c216c810 00000205 c1c09dd4 00000000 c27375b8
[ 2.097422] de40: c2091700 c0a6e9a0 c216c810 c0a6f288 c216c810 c1c09dd4 c216c810 00000000
[ 2.097430] de60: c27375b8 c0a6f3c0 c1caa8e0 c216c810 c216c810 c0a6f450 00000000 c216c810
[ 2.097439] de80: c1c09dd4 c2120000 c27375b8 c0a6f850 00000000 c1c09dd4 c0a6f7c4 c0a6d4c0
[ 2.097447] dea0: 00000000 c2091458 c2286434 5640e141 c1be7f08 c1c09dd4 c2737580 c1be7f08
[ 2.097455] dec0: 00000000 c0a6e484 c1615714 c1be7c50 c1c09dd4 c2120000 c189a99c 00000000
[ 2.097464] dee0: c2120000 c0a701a0 c1c494e0 c2120000 c189a99c c0302144 0000017d c0364438
[ 2.097472] df00: c16da8bc c1626700 00000000 00000006 00000006 c16554c8 00000000 c2120000
[ 2.097480] df20: c15105bc c14f9778 c2091700 c20917d9 00000000 5640e141 c1a88930 c16da8bc
[ 2.097488] df40: c1c59000 5640e141 c16da8bc c1c59000 c1953b4c c18d4834 00000007 c1801340
[ 2.097497] df60: 00000006 00000006 00000000 c18004dc c2120000 c18004dc f080df74 c1a04cc0
[ 2.097505] df80: c106bbf0 00000000 00000000 00000000 00000000 00000000 00000000 c106bc08
[ 2.097513] dfa0: 00000000 c106bbf0 00000000 c03001a8 00000000 00000000 00000000 00000000
[ 2.097520] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 2.097528] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[ 2.097542] devm_clk_release from release_nodes+0x58/0xc0
[ 2.097575] release_nodes from devres_release_all+0x7c/0xc0
[ 2.097596] devres_release_all from device_unbind_cleanup+0xc/0x60
[ 2.097626] device_unbind_cleanup from really_probe+0x1f4/0x2a8
[ 2.097650] really_probe from __driver_probe_device+0x84/0xe4
[ 2.097673] __driver_probe_device from driver_probe_device+0x30/0xd0
[ 2.097696] driver_probe_device from __driver_attach+0x8c/0xf0
[ 2.097713] __driver_attach from bus_for_each_dev+0x70/0xb0
[ 2.097729] bus_for_each_dev from bus_add_driver+0x168/0x1f4
[ 2.097749] bus_add_driver from driver_register+0x7c/0x118
[ 2.097766] driver_register from do_one_initcall+0x44/0x1ec
[ 2.097784] do_one_initcall from kernel_init_freeable+0x1d4/0x224
[ 2.097803] kernel_init_freeable from kernel_init+0x18/0x12c
[ 2.097820] kernel_init from ret_from_fork+0x14/0x2c
[ 2.097831] Exception stack(0xf080dfb0 to 0xf080dff8)
[ 2.097839] dfa0: 00000000 00000000 00000000 00000000
[ 2.097847] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 2.097854] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000
[ 2.097862] Code: c2288680 ffffffff 00000000 00000000 (c2288680)
[ 2.097872] ---[ end trace 0000000000000000 ]---

Let me know if you have any thoughts.

Cheers
Jon

--
nvpublic