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[v6,4/5] PCI: epf-mhi: Add wakeup host op

Message ID 20240710-wakeup_host-v6-4-ef00f31ea38d@quicinc.com (mailing list archive)
State New
Delegated to: Manivannan Sadhasivam
Headers show
Series PCI: EPC: Add support to wake up host from D3 states | expand

Commit Message

Krishna Chaitanya Chundru July 10, 2024, 11:16 a.m. UTC 
Add wakeup host op for MHI EPF.
If the D-state is in D3cold toggle wake signal, otherwise send PME.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
 drivers/pci/endpoint/functions/pci-epf-mhi.c | 11 +++++++++++
 include/linux/mhi_ep.h                       |  1 +
 2 files changed, 12 insertions(+)

Comments

Bjorn Helgaas July 11, 2024, 4:56 p.m. UTC | #1 
On Wed, Jul 10, 2024 at 04:46:11PM +0530, Krishna chaitanya chundru wrote:
> Add wakeup host op for MHI EPF.
> If the D-state is in D3cold toggle wake signal, otherwise send PME.

Feels racy.  Maybe it doesn't matter?  I guess it's unavoidable that
we could be in D3hot, commit to sending PME, and then main power goes
away so we're now in D3cold and the PME is not delivered?  Is there a
way to recover from that?

s/D-state is in D3cold/D-state is D3cold/
s/toggle wake/assert WAKE#/

Rewrap into single paragraph or add blank line between.
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Patch

diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/endpoint/functions/pci-epf-mhi.c
index 6de9014e6e53..82fc52490324 100644
--- a/drivers/pci/endpoint/functions/pci-epf-mhi.c
+++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
@@ -708,6 +708,16 @@  static int pci_epf_mhi_dma_init(struct pci_epf_mhi *epf_mhi)
 	return ret;
 }
 
+static int pci_epf_mhi_wakeup_host(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	struct pci_epf *epf = epf_mhi->epf;
+	struct pci_epc *epc = epf->epc;
+
+	return pci_epc_wakeup_host(epc, epf->func_no, epf->vfunc_no,
+			(mhi_cntrl->dstate == PCI_D3cold) ? false : true);
+}
+
 static void pci_epf_mhi_dma_deinit(struct pci_epf_mhi *epf_mhi)
 {
 	destroy_workqueue(epf_mhi->dma_wq);
@@ -803,6 +813,7 @@  static int pci_epf_mhi_link_up(struct pci_epf *epf)
 	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;
+	mhi_cntrl->wakeup_host = pci_epf_mhi_wakeup_host;
 	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;
diff --git a/include/linux/mhi_ep.h b/include/linux/mhi_ep.h
index 7c9e5895ea2c..04646cf7782b 100644
--- a/include/linux/mhi_ep.h
+++ b/include/linux/mhi_ep.h
@@ -165,6 +165,7 @@  struct mhi_ep_cntrl {
 	int (*write_sync)(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_buf_info *buf_info);
 	int (*read_async)(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_buf_info *buf_info);
 	int (*write_async)(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_buf_info *buf_info);
+	int (*wakeup_host)(struct mhi_ep_cntrl *mhi_cntrl);
 
 	enum mhi_state mhi_state;