Re: mtd: Use mtd device name instead of mtd->name when registering nvmem device

[Christophe Kerello <christophe.kerello@st.com>]

Hi Miquel,

On 11/25/19 4:37 PM, Miquel Raynal wrote:
> Miquel Raynal <miquel.raynal@bootlin.com> wrote on Mon, 25 Nov 2019
> 16:05:03 +0100:
> 
>> Hi Christophe,
>>
>> Christophe Kerello <christophe.kerello@st.com> wrote on Fri, 22 Nov
>> 2019 18:03:42 +0100:
>>
>>> MTD currently allows to have same partition name on different devices.
>>> Since nvmen device registration has been added, it is not more possible
>>> to have same partition name on different devices. We get following
>>> logs:
>>> sysfs: cannot create duplicate filename XXX
>>> Failed to register NVMEM device
>>>
>>> To avoid such issue, the proposed patch uses the mtd device name instead of
>>> the partition name.
>>>
>>> Fixes: c4dfa25ab307 ("mtd: add support for reading MTD devices via the nvmem API")
>>> Signed-off-by: Christophe Kerello <christophe.kerello@st.com>
>>> ---
>>> Hi,
>>>
>>> With latest mtd-next branch, we get following logs on our STM32MP1 eval board.
>>>
>>> [    1.979089] nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xd3
>>> [    1.984055] nand: Micron MT29F8G08ABACAH4
>>> [    1.988000] nand: 1024 MiB, SLC, erase size: 256 KiB, page size: 4096, OOB size: 224
>>> [    1.996378] Bad block table found at page 262080, version 0x01
>>> [    2.001945] Bad block table found at page 262016, version 0x01
>>> [    2.008002] 4 fixed-partitions partitions found on MTD device 58002000.nand-controller
>>> [    2.015398] Creating 4 MTD partitions on "58002000.nand-controller":
>>> [    2.021751] 0x000000000000-0x000000200000 : "fsbl"
>>> [    2.028506] 0x000000200000-0x000000400000 : "ssbl1"
>>> [    2.033741] 0x000000400000-0x000000600000 : "ssbl2"
>>> [    2.038924] 0x000000600000-0x000040000000 : "UBI"
>>> [    2.051336] spi-nor spi0.0: mx66l51235l (65536 Kbytes)
>>> [    2.055123] 4 fixed-partitions partitions found on MTD device spi0.0
>>> [    2.061378] Creating 4 MTD partitions on "spi0.0":
>>> [    2.066243] 0x000000000000-0x000000040000 : "fsbl"
>>> [    2.071429] sysfs: cannot create duplicate filename '/bus/nvmem/devices/fsbl'
>>> [    2.078157] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc4-00031-g589e1b6 #176
>>> [    2.085781] Hardware name: STM32 (Device Tree Support)
>>> [    2.090957] [<c0312830>] (unwind_backtrace) from [<c030cbe4>] (show_stack+0x10/0x14)
>>> [    2.098693] [<c030cbe4>] (show_stack) from [<c0e8d340>] (dump_stack+0xb4/0xc8)
>>> [    2.105929] [<c0e8d340>] (dump_stack) from [<c050fcdc>] (sysfs_warn_dup+0x58/0x64)
>>> [    2.113509] [<c050fcdc>] (sysfs_warn_dup) from [<c0510010>] (sysfs_do_create_link_sd+0xe4/0xe8)
>>> [    2.122224] [<c0510010>] (sysfs_do_create_link_sd) from [<c0956f60>] (bus_add_device+0x80/0xfc)
>>> [    2.130938] [<c0956f60>] (bus_add_device) from [<c0953f54>] (device_add+0x35c/0x608)
>>> [    2.138697] [<c0953f54>] (device_add) from [<c0d12e0c>] (nvmem_register.part.2+0x180/0x624)
>>> [    2.147065] [<c0d12e0c>] (nvmem_register.part.2) from [<c09ea5c8>] (add_mtd_device+0x2d8/0x4b8)
>>> [    2.155776] [<c09ea5c8>] (add_mtd_device) from [<c09edbd4>] (add_mtd_partitions+0x84/0x16c)
>>> [    2.164140] [<c09edbd4>] (add_mtd_partitions) from [<c09ed9ac>] (parse_mtd_partitions+0x220/0x3c4)
>>> [    2.173118] [<c09ed9ac>] (parse_mtd_partitions) from [<c09ea8d4>] (mtd_device_parse_register+0x40/0x164)
>>> [    2.182622] [<c09ea8d4>] (mtd_device_parse_register) from [<c0a22dfc>] (spi_nor_probe+0xd0/0x190)
>>> [    2.191513] [<c0a22dfc>] (spi_nor_probe) from [<c0a370a0>] (spi_drv_probe+0x80/0xa4)
>>> [    2.199268] [<c0a370a0>] (spi_drv_probe) from [<c0957f8c>] (really_probe+0x234/0x34c)
>>> [    2.207111] [<c0957f8c>] (really_probe) from [<c095821c>] (driver_probe_device+0x60/0x174)
>>> [    2.215391] [<c095821c>] (driver_probe_device) from [<c0956378>] (bus_for_each_drv+0x58/0xb8)
>>> [    2.223932] [<c0956378>] (bus_for_each_drv) from [<c0957ce4>] (__device_attach+0xd0/0x13c)
>>> [    2.232212] [<c0957ce4>] (__device_attach) from [<c0957060>] (bus_probe_device+0x84/0x8c)
>>> [    2.240404] [<c0957060>] (bus_probe_device) from [<c0953fb4>] (device_add+0x3bc/0x608)
>>> [    2.248334] [<c0953fb4>] (device_add) from [<c0a377b4>] (spi_add_device+0x9c/0x14c)
>>> [    2.256003] [<c0a377b4>] (spi_add_device) from [<c0a37b98>] (of_register_spi_device+0x234/0x370)
>>> [    2.264807] [<c0a37b98>] (of_register_spi_device) from [<c0a384ec>] (spi_register_controller+0x578/0x734)
>>> [    2.274394] [<c0a384ec>] (spi_register_controller) from [<c0a386dc>] (devm_spi_register_controller+0x34/0x6c)
>>> [    2.284331] [<c0a386dc>] (devm_spi_register_controller) from [<c0a4d0b8>] (stm32_qspi_probe+0x338/0x3bc)
>>> [    2.293831] [<c0a4d0b8>] (stm32_qspi_probe) from [<c0959ee0>] (platform_drv_probe+0x48/0x98)
>>> [    2.302285] [<c0959ee0>] (platform_drv_probe) from [<c0957f8c>] (really_probe+0x234/0x34c)
>>> [    2.310566] [<c0957f8c>] (really_probe) from [<c095821c>] (driver_probe_device+0x60/0x174)
>>> [    2.318847] [<c095821c>] (driver_probe_device) from [<c09584d8>] (device_driver_attach+0x58/0x60)
>>> [    2.327735] [<c09584d8>] (device_driver_attach) from [<c0958560>] (__driver_attach+0x80/0xbc)
>>> [    2.336276] [<c0958560>] (__driver_attach) from [<c09562cc>] (bus_for_each_dev+0x74/0xb4)
>>> [    2.344469] [<c09562cc>] (bus_for_each_dev) from [<c09572c4>] (bus_add_driver+0x164/0x1e8)
>>> [    2.352749] [<c09572c4>] (bus_add_driver) from [<c0958fd8>] (driver_register+0x74/0x108)
>>> [    2.360854] [<c0958fd8>] (driver_register) from [<c0302ec8>] (do_one_initcall+0x54/0x22c)
>>> [    2.369047] [<c0302ec8>] (do_one_initcall) from [<c1501024>] (kernel_init_freeable+0x150/0x1ec)
>>> [    2.377762] [<c1501024>] (kernel_init_freeable) from [<c0ea5e74>] (kernel_init+0x8/0x114)
>>> [    2.385951] [<c0ea5e74>] (kernel_init) from [<c03010e8>] (ret_from_fork+0x14/0x2c)
>>> [    2.393525] Exception stack(0xe68c1fb0 to 0xe68c1ff8)
>>> [    2.398583] 1fa0:                                     00000000 00000000 00000000 00000000
>>> [    2.406777] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
>>> [    2.414967] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
>>> [    2.421879] mtd mtd4: Failed to register NVMEM device
>>>
>>> Before nvmen device registration was added, it was possible to have same partition name on different devices.
>>> Instead of using the partition name, this patch proposes to use the MTD device name (mtdX).
>>>
>>> Regards,
>>> Christophe Kerello.
>>>
>>>   drivers/mtd/mtdcore.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
>>> index 5fac435..559b693 100644
>>> --- a/drivers/mtd/mtdcore.c
>>> +++ b/drivers/mtd/mtdcore.c
>>> @@ -551,7 +551,7 @@ static int mtd_nvmem_add(struct mtd_info *mtd)
>>>   
>>>   	config.id = -1;
>>>   	config.dev = &mtd->dev;
>>> -	config.name = mtd->name;
>>> +	config.name = dev_name(&mtd->dev);
>>
>> What about creating an mtd->fullname field which would be, for
>> partitions: mtdX:<partition-name> and would be unique?
> 
> The actual mtd->name (driver name or label if given) instead of the mtd
> number would be better. That would give things like "nand0:mypart".

Based on Steve's comment, it seems better to abandon this proposed fix. 
We will use unique partition names on our side.

Regards,
Christophe Kerello.

> 
>>
>>>   	config.owner = THIS_MODULE;
>>>   	config.reg_read = mtd_nvmem_reg_read;
>>>   	config.size = mtd->size;
>>
>> Thanks,
>> Miquèl
> 
> Thanks,
> Miquèl
>