This is a note to let you know that I've just added the patch titled
PCI: qcom-ep: Add dedicated callback for writing to DBI2 registers
to the 6.1-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-add-dedicated-callback-for-writing-to-db.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9e558c21c1c826b108b76d4155de58b8f8ae3b5b
Author: Manivannan Sadhasivam <mani@xxxxxxxxxx>
Date: Wed Oct 25 18:30:29 2023 +0530
PCI: qcom-ep: Add dedicated callback for writing to DBI2 registers
[ Upstream commit a07d2497ed657eb2efeb967af47e22f573dcd1d6 ]
The DWC core driver exposes the write_dbi2() callback for writing to the
DBI2 registers in a vendor-specific way.
On the Qcom EP platforms, the DBI_CS2 bit in the ELBI region needs to be
asserted before writing to any DBI2 registers and deasserted once done.
So, let's implement the callback for the Qcom PCIe EP driver so that the
DBI2 writes are correctly handled in the hardware.
Without this callback, the DBI2 register writes like BAR size won't go
through and as a result, the default BAR size is set for all BARs.
[kwilczynski: commit log, renamed function to match the DWC convention]
Fixes: f55fee56a631 ("PCI: qcom-ep: Add Qualcomm PCIe Endpoint controller driver")
Suggested-by: Serge Semin <fancer.lancer@xxxxxxxxx>
Link: https://lore.kernel.org/linux-pci/20231025130029.74693-2-manivannan.sadhasivam@xxxxxxxxxx
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@xxxxxxxxxx>
Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 5.16+
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 d4c566c1c8725..1c7fd05ce0280 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -120,6 +120,7 @@
/* ELBI registers */
#define ELBI_SYS_STTS 0x08
+#define ELBI_CS2_ENABLE 0xa4
/* DBI registers */
#define DBI_CON_STATUS 0x44
@@ -252,6 +253,21 @@ static void qcom_pcie_dw_stop_link(struct dw_pcie *pci)
disable_irq(pcie_ep->perst_irq);
}
+static void qcom_pcie_dw_write_dbi2(struct dw_pcie *pci, void __iomem *base,
+ u32 reg, size_t size, u32 val)
+{
+ struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
+ int ret;
+
+ writel(1, pcie_ep->elbi + ELBI_CS2_ENABLE);
+
+ ret = dw_pcie_write(pci->dbi_base2 + reg, size, val);
+ if (ret)
+ dev_err(pci->dev, "Failed to write DBI2 register (0x%x): %d\n", reg, ret);
+
+ writel(0, pcie_ep->elbi + ELBI_CS2_ENABLE);
+}
+
static int qcom_pcie_enable_resources(struct qcom_pcie_ep *pcie_ep)
{
int ret;
@@ -446,6 +462,7 @@ static const struct dw_pcie_ops pci_ops = {
.link_up = qcom_pcie_dw_link_up,
.start_link = qcom_pcie_dw_start_link,
.stop_link = qcom_pcie_dw_stop_link,
+ .write_dbi2 = qcom_pcie_dw_write_dbi2,
};
static int qcom_pcie_ep_get_io_resources(struct platform_device *pdev,
