From: Lucas Tanure <tanure@linux.com>
To: Linux Kernel List <kernelnewbies@kernelnewbies.org>
Subject: Questions about mfd_add_devices and platform_data
Date: Thu, 1 Aug 2019 17:05:21 +0100 [thread overview]
Message-ID: <CAJX_Q+2OmPa0jNG135z4zUCet=jVXnoaEQereT1oYcFPoWaWDg@mail.gmail.com> (raw)
In-Reply-To: <CACYKDtghiTsv8zGgoVvuQHqo=dmt_22GrK9xie-Y-3sNkiFfrw@mail.gmail.com>
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Hi,
I would like to understand mfd_add_devices call and platform_data section.
All the drivers I read the platform_data is static, but mfd_add_devices
will call platform_device_add_data which duplicates that memory and frees
the first pointer given.
But the first pointer is static and kfrees says:
"Don't free memory not originally allocated by kmalloc() or you will run
into trouble."
So, my questions is : Should my driver kmalloc platform_data first and then
call mfd_add_devices ? Or it's fine to give static memory to it ?
Example driver:
drivers/mfd/vexpress-sysreg.c:
static struct syscon_platform_data vexpress_sysreg_sys_id_pdata = {
.label = "sys_id",
};
static struct mfd_cell vexpress_sysreg_cells[] = {
{
.name = "syscon",
.num_resources = 1,
.resources = (struct resource []) {
DEFINE_RES_MEM(SYS_ID, 0x4),
},
.platform_data = &vexpress_sysreg_sys_id_pdata,
.pdata_size = sizeof(vexpress_sysreg_sys_id_pdata),
},
For this case mfd_add_devices will free vexpress_sysreg_sys_id_pdata, but
it's static.
Thanks
Lucas
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prev parent reply other threads:[~2019-08-01 16:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-26 23:56 WOL from S5 (shutdown) Abu Rasheda
2019-07-31 19:32 ` Abu Rasheda
2019-08-01 16:05 ` Lucas Tanure [this message]
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