On 9/23/24 21:27, Wei Huang wrote:
On 9/23/24 7:07 AM, Alejandro Lucero Palau wrote:
...
+/**
+ * pcie_enable_tph - Enable TPH support for device using a specific
ST mode
+ * @pdev: PCI device
+ * @mode: ST mode to enable. Current supported modes include:
+ *
+ * - PCI_TPH_ST_NS_MODE: NO ST Mode
+ * - PCI_TPH_ST_IV_MODE: Interrupt Vector Mode
+ * - PCI_TPH_ST_DS_MODE: Device Specific Mode
+ *
+ * Checks whether the mode is actually supported by the device
before enabling
+ * and returns an error if not. Additionally determines what types
of requests,
+ * TPH or extended TPH, can be issued by the device based on its
TPH requester
+ * capability and the Root Port's completer capability.
+ *
+ * Return: 0 on success, otherwise negative value (-errno)
+ */
+int pcie_enable_tph(struct pci_dev *pdev, int mode)
+{
+ u32 reg;
+ u8 dev_modes;
+ u8 rp_req_type;
+
+ /* Honor "notph" kernel parameter */
+ if (pci_tph_disabled)
+ return -EINVAL;
+
+ if (!pdev->tph_cap)
+ return -EINVAL;
+
+ if (pdev->tph_enabled)
+ return -EBUSY;
+
+ /* Sanitize and check ST mode comptability */
+ mode &= PCI_TPH_CTRL_MODE_SEL_MASK;
+ dev_modes = get_st_modes(pdev);
+ if (!((1 << mode) & dev_modes))
This is wrong. The mode definition is about the bit on and not about bit
position. You got this right in v4 ...
This code is correct. In V5, I changed the "mode" parameter to the
following values, as defined in TPH Ctrl register. These values are
defined as bit positions:
PCI_TPH_ST_NS_MODE: NO ST Mode
PCI_TPH_ST_IV_MODE: Interrupt Vector Mode
PCI_TPH_ST_DS_MODE: Device Specific Mode
OK. I found the issue. I was using PCI_TPH_CAP_ST_DS for the mode
instead of PCI_TPH_ST_DS_MODE.
That change confused me.
Apologies.
In V4, "mode" is defined as masks of TPH Cap register. I felt that V5
looks more straightforward:
V4: pcie_enable_tph(dev, PCI_TPH_CAP_ST_IV)
vs.
V5: pcie_enable_tph(dev, PCI_TPH_ST_IV_MODE)
+ return -EINVAL;
