On 5/15/2023 5:06 PM, Manivannan Sadhasivam wrote:
Hi Kishon,
On Mon, May 15, 2023 at 01:37:28PM +0530, Kishon VijayAbraham I wrote:
Hi Manivannan,
On 3/14/2023 10:16 AM, Manivannan Sadhasivam wrote:
Add PCI Endpoint driver for the Qualcomm MHI (Modem Host Interface) bus.
The driver implements the MHI function over PCI in the endpoint device
such as SDX55 modem. The MHI endpoint function driver acts as a
controller driver for the MHI Endpoint stack and carries out all PCI
related activities like mapping the host memory using iATU, triggering
MSIs etc...
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
---
drivers/pci/endpoint/functions/Kconfig | 10 +
drivers/pci/endpoint/functions/Makefile | 1 +
drivers/pci/endpoint/functions/pci-epf-mhi.c | 454 +++++++++++++++++++
3 files changed, 465 insertions(+)
create mode 100644 drivers/pci/endpoint/functions/pci-epf-mhi.c
diff --git a/drivers/pci/endpoint/functions/Kconfig b/drivers/pci/endpoint/functions/Kconfig
index 9fd560886871..f5171b4fabbe 100644
--- a/drivers/pci/endpoint/functions/Kconfig
+++ b/drivers/pci/endpoint/functions/Kconfig
@@ -37,3 +37,13 @@ config PCI_EPF_VNTB
between PCI Root Port and PCIe Endpoint.
If in doubt, say "N" to disable Endpoint NTB driver.
+
+config PCI_EPF_MHI
+ tristate "PCI Endpoint driver for MHI bus"
+ depends on PCI_ENDPOINT && MHI_BUS_EP
+ help
+ Enable this configuration option to enable the PCI Endpoint
+ driver for Modem Host Interface (MHI) bus in Qualcomm Endpoint
+ devices such as SDX55.
+
+ If in doubt, say "N" to disable Endpoint driver for MHI bus.
diff --git a/drivers/pci/endpoint/functions/Makefile b/drivers/pci/endpoint/functions/Makefile
index 5c13001deaba..696473fce50e 100644
--- a/drivers/pci/endpoint/functions/Makefile
+++ b/drivers/pci/endpoint/functions/Makefile
@@ -6,3 +6,4 @@
obj-$(CONFIG_PCI_EPF_TEST) += pci-epf-test.o
obj-$(CONFIG_PCI_EPF_NTB) += pci-epf-ntb.o
obj-$(CONFIG_PCI_EPF_VNTB) += pci-epf-vntb.o
+obj-$(CONFIG_PCI_EPF_MHI) += pci-epf-mhi.o
diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/endpoint/functions/pci-epf-mhi.c
new file mode 100644
index 000000000000..03e7f42663b3
--- /dev/null
+++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
.
.
<snip>
.
.
+static int pci_epf_mhi_link_up(struct pci_epf *epf)
+{
+ struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
+ const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
+ struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
+ struct pci_epc *epc = epf->epc;
+ struct device *dev = &epf->dev;
+ int ret;
+
+ mhi_cntrl->mmio = epf_mhi->mmio;
+ mhi_cntrl->irq = epf_mhi->irq;
+ mhi_cntrl->mru = info->mru;
+
+ /* Assign the struct dev of PCI EP as MHI controller device */
+ mhi_cntrl->cntrl_dev = epc->dev.parent;
+ 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_from_host = pci_epf_mhi_read_from_host;
+ mhi_cntrl->write_to_host = pci_epf_mhi_write_to_host;
+
+ /* Register the MHI EP controller */
+ ret = mhi_ep_register_controller(mhi_cntrl, info->config);
+ if (ret) {
+ dev_err(dev, "Failed to register MHI EP controller: %d\n", ret);
+ return ret;
+ }
Any reason for delaying registration with MHI bus till link up? Since after
linkup, the host can start using the device, this should be doing minimal
stuff IMHO. Or is there further handshake between the host side MHI driver
and the endpoint side MHI driver?
Yes, there are further handshakes required between ep and host before the host
can start using MHI and this is done during mhi_ep_power_up(). Moreover,
registering the controller during link_up event allows us to do cleanup properly
when the link goes down.
Thank you for clarifying!
For the entire series:
Reviewed-by: Kishon Vijay Abraham I <kishon@xxxxxxxxxx>
- Mani
Thanks,
Kishon
