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bus: mhi: host: Add a new API for getting channel doorbell offset

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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 <quic_qianyu@quicinc.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
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 <manivannan.sadhasivam@linaro.org>
This commit is contained in:
Qiang Yu 2024-04-24 11:21:54 +08:00 committed by Manivannan Sadhasivam
parent 17553ba8e1
commit 553f94fc76
3 changed files with 28 additions and 5 deletions
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8
drivers/bus/mhi/host/init.c
View File

@ -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",

16
drivers/bus/mhi/host/main.c
View File

@ -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);

9
include/linux/mhi.h
View File

@ -816,4 +816,13 @@ int mhi_queue_skb(struct mhi_device *mhi_dev, enum dma_data_direction dir,
*/
bool mhi_queue_is_full(struct mhi_device *mhi_dev, enum dma_data_direction dir);
/**
* mhi_get_channel_doorbell_offset - Get the channel doorbell offset
* @mhi_cntrl: MHI controller
* @chdb_offset: Read channel doorbell offset
*
* Return: 0 if the read succeeds, a negative error code otherwise
*/
int mhi_get_channel_doorbell_offset(struct mhi_controller *mhi_cntrl, u32 *chdb_offset);
#endif /* _MHI_H_ */