From 553f94fc7667259e47a9318e9e5702c9a814d637 Mon Sep 17 00:00:00 2001 From: Qiang Yu Date: Wed, 24 Apr 2024 11:21:54 +0800 Subject: bus: mhi: host: Add a new API for getting channel doorbell offset Some controllers may want to access a specific doorbell register. Hence add a new API that reads the CHDBOFF register and returns the offset of the doorbell registers from MMIO base, so that the controller can calculate the address of the specific doorbell register by adding the register offset with doorbell offset and MMIO base address. Signed-off-by: Qiang Yu Reviewed-by: Jeffrey Hugo Link: https://lore.kernel.org/r/1713928915-18229-3-git-send-email-quic_qianyu@quicinc.com [mani: reworded commit message and Kdoc] Signed-off-by: Manivannan Sadhasivam --- drivers/bus/mhi/host/init.c | 8 +++----- drivers/bus/mhi/host/main.c | 16 ++++++++++++++++ 2 files changed, 19 insertions(+), 5 deletions(-) (limited to 'drivers/bus') diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c index 7104c1856987..173f79918741 100644 --- a/drivers/bus/mhi/host/init.c +++ b/drivers/bus/mhi/host/init.c @@ -541,11 +541,9 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl) dev_dbg(dev, "Initializing MHI registers\n"); /* Read channel db offset */ - ret = mhi_read_reg(mhi_cntrl, base, CHDBOFF, &val); - if (ret) { - dev_err(dev, "Unable to read CHDBOFF register\n"); - return -EIO; - } + ret = mhi_get_channel_doorbell_offset(mhi_cntrl, &val); + if (ret) + return ret; if (val >= mhi_cntrl->reg_len - (8 * MHI_DEV_WAKE_DB)) { dev_err(dev, "CHDB offset: 0x%x is out of range: 0x%zx\n", diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index 15d657af9b5b..4de75674f193 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -1691,3 +1691,19 @@ void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev) } } EXPORT_SYMBOL_GPL(mhi_unprepare_from_transfer); + +int mhi_get_channel_doorbell_offset(struct mhi_controller *mhi_cntrl, u32 *chdb_offset) +{ + struct device *dev = &mhi_cntrl->mhi_dev->dev; + void __iomem *base = mhi_cntrl->regs; + int ret; + + ret = mhi_read_reg(mhi_cntrl, base, CHDBOFF, chdb_offset); + if (ret) { + dev_err(dev, "Unable to read CHDBOFF register\n"); + return -EIO; + } + + return 0; +} +EXPORT_SYMBOL_GPL(mhi_get_channel_doorbell_offset); -- cgit v1.2.3