This is a note to let you know that I've just added the patch titled
PCI: qcom-ep: Switch MHI bus master clock off during L1SS
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-qcom-ep-switch-mhi-bus-master-clock-off-during-l.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit facd24254a780a16455e714389e83fad5e305ed9
Author: Manivannan Sadhasivam <mani@xxxxxxxxxx>
Date: Tue Jun 27 19:40:36 2023 +0530
PCI: qcom-ep: Switch MHI bus master clock off during L1SS
[ Upstream commit b9cbc06049cb6b7a322d708c2098195fb9fdcc4c ]
Currently, as part of the qcom_pcie_perst_deassert() function, instead
of writing the updated value to clear PARF_MSTR_AXI_CLK_EN, the variable
"val" is re-read.
This must be fixed to ensure that the master clock supplied to the MHI
bus is correctly gated during L1.1/L1.2 to save power.
Thus, replace the line that re-reads "val" with a line that writes the
updated value to the register to clear PARF_MSTR_AXI_CLK_EN.
[kwilczynski: commit log]
Fixes: c457ac029e44 ("PCI: qcom-ep: Gate Master AXI clock to MHI bus during L1SS")
Link: https://lore.kernel.org/linux-pci/20230627141036.11600-1-manivannan.sadhasivam@xxxxxxxxxx
Reported-by: Krzysztof Wilczyński <kwilczynski@xxxxxxxxxx>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
index 19b32839ea261..043b356d7d72d 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -415,7 +415,7 @@ static int qcom_pcie_perst_deassert(struct dw_pcie *pci)
/* Gate Master AXI clock to MHI bus during L1SS */
val = readl_relaxed(pcie_ep->parf + PARF_MHI_CLOCK_RESET_CTRL);
val &= ~PARF_MSTR_AXI_CLK_EN;
- val = readl_relaxed(pcie_ep->parf + PARF_MHI_CLOCK_RESET_CTRL);
+ writel_relaxed(val, pcie_ep->parf + PARF_MHI_CLOCK_RESET_CTRL);
dw_pcie_ep_init_notify(&pcie_ep->pci.ep);
