Re: [PATCH 6/9] PCI: epf-mhi: Enable MHI async read/write support

From: Krishna Chaitanya Chundru
Date: Thu Dec 14 2023 - 05:14:46 EST



On 12/14/2023 3:39 PM, Manivannan Sadhasivam wrote:
On Thu, Dec 14, 2023 at 03:10:01PM +0530, Krishna Chaitanya Chundru wrote:
On 11/27/2023 6:15 PM, Manivannan Sadhasivam wrote:
Now that both eDMA and iATU are prepared to support async transfer, let's
enable MHI async read/write by supplying the relevant callbacks.

In the absence of eDMA, iATU will be used for both sync and async
operations.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
---
drivers/pci/endpoint/functions/pci-epf-mhi.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/endpoint/functions/pci-epf-mhi.c
index 3d09a37e5f7c..d3d6a1054036 100644
--- a/drivers/pci/endpoint/functions/pci-epf-mhi.c
+++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
@@ -766,12 +766,13 @@ static int pci_epf_mhi_link_up(struct pci_epf *epf)
mhi_cntrl->raise_irq = pci_epf_mhi_raise_irq;
mhi_cntrl->alloc_map = pci_epf_mhi_alloc_map;
mhi_cntrl->unmap_free = pci_epf_mhi_unmap_free;
+ mhi_cntrl->read_sync = mhi_cntrl->read_async = pci_epf_mhi_iatu_read;
+ mhi_cntrl->write_sync = mhi_cntrl->write_async = pci_epf_mhi_iatu_write;
if (info->flags & MHI_EPF_USE_DMA) {
mhi_cntrl->read_sync = pci_epf_mhi_edma_read;
mhi_cntrl->write_sync = pci_epf_mhi_edma_write;
- } else {
- mhi_cntrl->read_sync = pci_epf_mhi_iatu_read;
- mhi_cntrl->write_sync = pci_epf_mhi_iatu_write;
+ mhi_cntrl->read_async = pci_epf_mhi_edma_read_async;
+ mhi_cntrl->write_async = pci_epf_mhi_edma_write_async;
I think the read_async & write async should be updated inside the if
condition where MHI_EPF_USE_DMA flag is set.

That's what being done here. Am I missing anything?

- Mani

It should be like this as edma sync & aysnc read write should be update only if DMA is supported, in the patch I see async function pointers are being updated with the edma function pointers for IATU operations.

                if (info->flags & MHI_EPF_USE_DMA) {

mhi_cntrl->read_sync = pci_epf_mhi_edma_read;
mhi_cntrl->write_sync = pci_epf_mhi_edma_write;
mhi_cntrl->read_async = pci_epf_mhi_edma_read_async;
mhi_cntrl->write_async = pci_epf_mhi_edma_write_async;
}
- Krishna Chaitanya.

- Krishna Chaitanya.

}
/* Register the MHI EP controller */