Re: [PATCH] PCI: qcom: configure the parf halt window size to 1GB

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On 6/24/2023 11:53 AM, Manivannan Sadhasivam wrote:
On Fri, Jun 23, 2023 at 10:27:31AM +0530, Devi Priya wrote:
Configure the ADDR_BIT_INDEX of PARF_AXI_MSTR_WR_ADDR_HALT_V2 register with
0x1E to increase the halt window size to 1GB so that, when new inbound
posted write transactions whose address crosses 1G address range, the
controller would halt all the incoming writes until all the previous AXI
responses are received.


Can you explain how the value of 0x1e corresponds to 1GB window size?
2^30 (0x1e) = 1G

Signed-off-by: Devi Priya <quic_devipriy@xxxxxxxxxxx>
---
  This patch depends on the below series which adds support for PCIe
  controllers in IPQ9574
  https://lore.kernel.org/linux-arm-msm/20230519090219.15925-1-quic_devipriy@xxxxxxxxxxx/

  drivers/pci/controller/dwc/pcie-qcom.c | 9 +++++++++
  1 file changed, 9 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index c7579dfa5b1c..26c40e006120 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -116,6 +116,8 @@
/* PARF_AXI_MSTR_WR_ADDR_HALT register fields */
  #define EN					BIT(31)
+#define ADDR_BIT_INDEX				(BIT(0) | BIT(1) | BIT(2) | \
+						BIT(3) | BIT(4) | BIT(5))

GENMASK(5, 0)
okay

/* PARF_LTSSM register fields */
  #define LTSSM_EN				BIT(8)
@@ -154,6 +156,8 @@
#define QCOM_PCIE_CRC8_POLYNOMIAL (BIT(2) | BIT(1) | BIT(0)) +#define PARF_AXI_MSTR_WR_ADDR_HALT_WINDOW_SIZE 0x1e

GENMASK(4, 1) as these are address bits.
okay

Thanks,
Devi Priya

- Mani

+
  #define QCOM_PCIE_1_0_0_MAX_CLOCKS		4
  struct qcom_pcie_resources_1_0_0 {
  	struct clk_bulk_data clks[QCOM_PCIE_1_0_0_MAX_CLOCKS];
@@ -1126,6 +1130,11 @@ static int qcom_pcie_post_init(struct qcom_pcie *pcie)
writel(0, pcie->parf + PARF_Q2A_FLUSH); + val = readl(pcie->parf + PARF_AXI_MSTR_WR_ADDR_HALT_V2);
+	val &= ~ADDR_BIT_INDEX;
+	writel(val | PARF_AXI_MSTR_WR_ADDR_HALT_WINDOW_SIZE, pcie->parf +
+			PARF_AXI_MSTR_WR_ADDR_HALT_V2);
+
  	dw_pcie_dbi_ro_wr_en(pci);
  	writel(PCIE_CAP_SLOT_VAL, pci->dbi_base + offset + PCI_EXP_SLTCAP);
--
2.17.1





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