Previously, the driver has been introduced to support the Loongson 2K BMC running on the Loongson Servers, which is essential to prevent the system from hanging when the BMC is being reset and the default efi-framebuffer is being used. However, there are some drawbacks in the driver.
Firstly, the driver tries to read and write to the connected PCI-E host controller registers, assuming that the BMC is connected to LS7A PCI-E host controller. This assumption should be true for real products, but to prevent from accidentally reading and writing to the wrong PCI-E host controller, this driver should be modified to check this before accessing the registers. Secondly, the driver uses non-exported functions to tell the vt subsystem to redraw the screen, preventing the driver from being compiling as a module. This can be fixed by using the exported functions instead. Thirdly, the driver directly accesses the GPIO controller registers using hard-coded addresses, which might conflict with the loaded GPIO controller driver for the same GPIO controller. This is fixed in this series by using the GPIO subsystem APIs instead. However, legacy GPIO APIs have to be used in this fixed to correctly request a GPIO descriptor from the GPIO subsystem, which might be further discussed to find a better solution. Finally, there is a minor issue in the driver where it changes the mode string describing the screen resolution during probing, which prevents the device from being probed again if -EPROBE_DEFER is returned by the probe function. I have tested the changes in this series on a single-socket Loongson 3C6000 server with a Loongson 2K BMC, and the driver works as expected when the corresponding GPIO driver is additionally loaded. Signed-off-by: Miao Wang <[email protected]> --- Changes in v3: - Check the return value of devm_add_action_or_reset when registering the cleanup hook of the work queue - Use swnode to create the link between the device to the GPIO chip, and prevent borrowing the legacy GPIO APIs - Link to v2: https://lore.kernel.org/r/[email protected] Changes in v2: - Several fixes suggested by the Sashiko AI review bot - Add a cleanup function for the wq on removal of the device - Relax the reverse dependency from CONFIG_IPMI_LS2K to CONFIG_MFD_LS2K_BMC_CORE to allow the driver to be built as a module - Link to v1: https://lore.kernel.org/r/[email protected] --- Miao Wang (7): mfd: ls2kbmc: Make a copy when parsing mode string mfd: ls2kbmc: Sanity check for the connected pci port mfd: ls2kbmc: Redraw using exported functions mfd: ls2kbmc: Cancel the work queue on removal ipmi: ls2k: Relax the dependency to its mfd driver mfd: ls2kbmc: Able to be compiled as a module mfd: ls2kbmc: Capture the reset event of BMC through GPIO drivers/char/ipmi/Kconfig | 2 +- drivers/mfd/Kconfig | 2 +- drivers/mfd/ls2k-bmc-core.c | 235 ++++++++++++++++++++++++++++++++++---------- 3 files changed, 184 insertions(+), 55 deletions(-) --- base-commit: 0e35b9b6ec0ffcc5e23cbdec09f5c622ad532b53 change-id: 20260626-ls2kbmc-mod-5209193009b2 Best regards, -- Miao Wang <[email protected]> _______________________________________________ Openipmi-developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/openipmi-developer
