can: sja1000: fix isr hang when hw is unplugged under load
can: sja1000: fix isr hang when hw is unplugged under load

In the case of hotplug enabled devices (PCMCIA/PCIeC) the removal of the
hardware can cause an infinite loop in the common sja1000 isr.

Use the already retrieved status register to indicate a possible hardware
removal and double check by reading the mode register in sja1000_is_absent.

Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@kernel.org [3.2+]
Signed-off-by: Oliver Hartkopp <06a38fb2ed1a2d0a17f4f06761ac2e5ace5a31ab@hartkopp.net>
Acked-by: Wolfgang Grandegger <5aa1976eca1fee4e35c7b71ec8e8a0ebad9da3d1@grandegger.com>
Signed-off-by: Marc Kleine-Budde <4a0ea1158d3cc63151119c05b1bff00c0bdbf421@pengutronix.de>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas