diff mbox series

[5/7] xen/arm: rcar4: add delay after programming ATU

Message ID 5837e6b60b413a3ea137fed1a59003bf2e2fb336.1740382735.git.mykyta_poturai@epam.com (mailing list archive)
State New
Headers show
Series Add support for R-Car Gen4 PCI host controller | expand

Commit Message

Mykyta Poturai Feb. 24, 2025, 9:18 a.m. UTC 
From: Volodymyr Babchuk <volodymyr_babchuk@epam.com>

For some reason, we need a delay before accessing ATU region after
we programmed it. Otherwise, we'll get erroneous TLP.

There is a code below, which should do this in proper way, by polling
CTRL2 register, but according to documentation, hardware does not
change this ATU_ENABLE bit at all.

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Signed-off-by: Mykyta Poturai <mykyta_poturai@epam.com>
---
 xen/arch/arm/pci/pci-host-rcar4.c | 5 +++++
 1 file changed, 5 insertions(+)
diff mbox series

Patch

diff --git a/xen/arch/arm/pci/pci-host-rcar4.c b/xen/arch/arm/pci/pci-host-rcar4.c
index df337e3159..3b97bf138a 100644
--- a/xen/arch/arm/pci/pci-host-rcar4.c
+++ b/xen/arch/arm/pci/pci-host-rcar4.c
@@ -289,6 +289,11 @@  static void dw_pcie_prog_outbound_atu_unroll(struct pci_host_bridge *pci,
     dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_REGION_CTRL2,
                              PCIE_ATU_ENABLE);
 
+    /*
+     * HACK: We need to delay there, because the next code does not
+     * work as expected on S4
+     */
+    mdelay(1);
     /*
      * Make sure ATU enable takes effect before any subsequent config
      * and I/O accesses.