Commit Graph

3 Commits

Author SHA1 Message Date
Arnd Bergmann c7cefce03e hwmon: (xgene) access mailbox as RAM
The newly added hwmon driver fails to build in an allmodconfig
kernel:

      ERROR: "memblock_is_memory" [drivers/hwmon/xgene-hwmon.ko] undefined!

According to comments in the code, the mailbox is a shared memory region,
not a set of MMIO registers, so we should use memremap() for mapping it
instead of ioremap or acpi_os_ioremap, and pointer dereferences instead
of readl/writel.

The driver already uses plain kernel pointers, so it's a bit unusual
to work with functions that operate on __iomem pointers, and this
fixes that part too.

I'm using READ_ONCE/WRITE_ONCE here to keep the existing behavior
regarding the ordering of the accesses from the CPU, but note that
there are no barriers (also unchanged from before).

I'm also keeping the endianness behavior, though I'm unsure whether
the message data was supposed to be in LE32 format in the first
place, it's possible this was meant to be interpreted as a byte
stream instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hoan Tran <hotran@apm.com>
Tested-by: Hoan Tran <hotran@apm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-09-09 14:54:53 -07:00
hotran 2ca492e22c hwmon: (xgene) Fix crash when alarm occurs before driver probe
The system crashes during probing xgene-hwmon driver when temperature
alarm interrupt occurs before.
It's because
 - xgene_hwmon_probe() requests mailbox channel which also enables
   the mailbox interrupt.
 - As temperature alarm interrupt is pending, ISR runs and crashes when
   accesses into invalid resourse as unmapped PCC shared memory.

This patch fixes this issue by saving this alarm message and scheduling a
bottom handler after xgene_hwmon_probe() finish.

Signed-off-by: Hoan Tran <hotran@apm.com>
Reported-by: Itaru Kitayama <itaru.kitayama@riken.jp>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-09-08 21:34:17 -07:00
hotran ed42cfa881 hwmon: Add xgene hwmon driver
This patch adds hardware temperature and power reading support for
APM X-Gene SoC using the mailbox communication interface.

Signed-off-by: Hoan Tran <hotran@apm.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-09-08 21:34:16 -07:00