From 8286ae03308c6f97f346f9f8cb9174b04969add5 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Wed, 25 Mar 2015 15:39:50 +0000 Subject: MIPS: Add CDMM bus support Add MIPS Common Device Memory Map (CDMM) support in the form of a bus in the standard Linux device model. Each device attached via CDMM is discoverable via an 8-bit type identifier and may contain a number of blocks of memory mapped registers in the CDMM region. IRQs are expected to be handled separately. Due to the per-cpu (per-VPE for MT cores) nature of the CDMM devices, all the driver callbacks take place from workqueues which are run on the right CPU for the device in question, so that the driver doesn't need to be as concerned about which CPU it is running on. Callbacks also exist for when CPUs are taken offline, so that any per-CPU resources used by the driver can be disabled so they don't get forcefully migrated. CDMM devices are created as children of the CPU device they are attached to. Any existing CDMM configuration by the bootloader will be inherited, however platforms wishing to enable CDMM should implement the weak mips_cdmm_phys_base() function (see asm/cdmm.h) so that the bus driver knows where it should put the CDMM region in the physical address space if the bootloader hasn't already enabled it. A mips_cdmm_early_probe() function is also provided to allow early boot or particularly low level code to set up the CDMM region and probe for a specific device type, for example early console or KGDB IO drivers for the EJTAG Fast Debug Channel (FDC) CDMM device. Signed-off-by: James Hogan Cc: Greg Kroah-Hartman Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/9599/ Signed-off-by: Ralf Baechle --- drivers/bus/Kconfig | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/bus/Kconfig') diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig index b99729e36860..cbddbaddb347 100644 --- a/drivers/bus/Kconfig +++ b/drivers/bus/Kconfig @@ -20,6 +20,19 @@ config IMX_WEIM The WEIM(Wireless External Interface Module) works like a bus. You can attach many different devices on it, such as NOR, onenand. +config MIPS_CDMM + bool "MIPS Common Device Memory Map (CDMM) Driver" + depends on CPU_MIPSR2 + help + Driver needed for the MIPS Common Device Memory Map bus in MIPS + cores. This bus is for per-CPU tightly coupled devices such as the + Fast Debug Channel (FDC). + + For this to work, either your bootloader needs to enable the CDMM + region at an unused physical address on the boot CPU, or else your + platform code needs to implement mips_cdmm_phys_base() (see + asm/cdmm.h). + config MVEBU_MBUS bool depends on PLAT_ORION -- cgit v1.2.3