From b5a8d233a588b3acf2a7a3a8da30f8f68f376626 Mon Sep 17 00:00:00 2001 From: Loic Poulain Date: Mon, 4 Jan 2021 17:14:50 +0100 Subject: [PATCH] bus: mhi: core: Add device hardware reset support The MHI specification allows to perform a hard reset of the device when writing to the SOC_RESET register. It can be used to completely restart the device (e.g. in case of unrecoverable MHI error). This is up to the MHI controller driver to determine when this hard reset should be used, and in case of MHI errors, should be used as a reset of last resort (after standard MHI stack reset). This function is a stateless function, the MHI layer do nothing except triggering the reset by writing into the right register(s), this is up to the caller to ensure right mhi_controller state (e.g. unregister the controller if necessary). Signed-off-by: Loic Poulain Reviewed-by: Manivannan Sadhasivam Signed-off-by: Manivannan Sadhasivam --- drivers/bus/mhi/core/main.c | 13 +++++++++++++ include/linux/mhi.h | 9 +++++++++ 2 files changed, 22 insertions(+) diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c index d34d7e9..9b42540 100644 --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -135,6 +135,19 @@ enum mhi_state mhi_get_mhi_state(struct mhi_controller *mhi_cntrl) } EXPORT_SYMBOL_GPL(mhi_get_mhi_state); +void mhi_soc_reset(struct mhi_controller *mhi_cntrl) +{ + if (mhi_cntrl->reset) { + mhi_cntrl->reset(mhi_cntrl); + return; + } + + /* Generic MHI SoC reset */ + mhi_write_reg(mhi_cntrl, mhi_cntrl->regs, MHI_SOC_RESET_REQ_OFFSET, + MHI_SOC_RESET_REQ); +} +EXPORT_SYMBOL_GPL(mhi_soc_reset); + int mhi_map_single_no_bb(struct mhi_controller *mhi_cntrl, struct mhi_buf_info *buf_info) { diff --git a/include/linux/mhi.h b/include/linux/mhi.h index 562862f..54afcae 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -347,6 +347,7 @@ struct mhi_controller_config { * @unmap_single: CB function to destroy TRE buffer * @read_reg: Read a MHI register via the physical link (required) * @write_reg: Write a MHI register via the physical link (required) + * @reset: Controller specific reset function (optional) * @buffer_len: Bounce buffer length * @index: Index of the MHI controller instance * @bounce_buf: Use of bounce buffer @@ -437,6 +438,7 @@ struct mhi_controller { u32 *out); void (*write_reg)(struct mhi_controller *mhi_cntrl, void __iomem *addr, u32 val); + void (*reset)(struct mhi_controller *mhi_cntrl); size_t buffer_len; int index; @@ -673,6 +675,13 @@ enum mhi_ee_type mhi_get_exec_env(struct mhi_controller *mhi_cntrl); enum mhi_state mhi_get_mhi_state(struct mhi_controller *mhi_cntrl); /** + * mhi_soc_reset - Trigger a device reset. This can be used as a last resort + * to reset and recover a device. + * @mhi_cntrl: MHI controller + */ +void mhi_soc_reset(struct mhi_controller *mhi_cntrl); + +/** * mhi_device_get - Disable device low power mode * @mhi_dev: Device associated with the channel */ -- 2.7.4