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Date: Mon, 2 Jan 2017 22:34:14 -0800
From: Rajat Jain <rajatja@...gle.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
Keith Busch <keith.busch@...el.com>,
Andreas Ziegler <andreas.ziegler@....de>,
Jonathan Yong <jonathan.yong@...el.com>,
Shawn Lin <shawn.lin@...k-chips.com>,
David Daney <david.daney@...ium.com>,
Julia Lawall <Julia.Lawall@...6.fr>,
Ram Amrani <Ram.Amrani@...ium.com>,
Doug Ledford <dledford@...hat.com>,
Wang Sheng-Hui <shhuiw@...mail.com>, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Rajat Jain <rajatja@...gle.com>, Rajat Jain <rajatxjain@...il.com>,
Brian Norris <briannorris@...gle.com>
Subject: [PATCH 5/6] PCI/ASPM: Actually configure the L1 substate settings to the device
Add code to actually configure the L1 substate settigns on the
upstream and downstream device, while taking care of the rules
dictated by the PCIe spec.
Signed-off-by: Rajat Jain <rajatja@...gle.com>
---
drivers/pci/pcie/aspm.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 104 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index a70afdf..6735f38 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -588,6 +588,92 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
}
}
+static inline void pci_clear_and_set_dword(struct pci_dev *pdev, int pos,
+ u32 clear, u32 set)
+{
+ u32 val;
+
+ pci_read_config_dword(pdev, pos, &val);
+ val &= ~clear;
+ val |= set;
+ pci_write_config_dword(pdev, pos, val);
+}
+
+/* Configure the ASPM L1 substates */
+static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state)
+{
+ u32 val, enable_req;
+ struct pci_dev *child = link->downstream, *parent = link->pdev;
+ u32 up_cap_ptr = link->l1ss.up_cap_ptr;
+ u32 dw_cap_ptr = link->l1ss.dw_cap_ptr;
+
+ enable_req = (link->aspm_enabled ^ state) & state;
+
+ /*
+ * Here are the rules specified in the PCIe spec for enabling L1SS:
+ * - When enabling L1.x, enable bit at parent first, then at child
+ * - When disabling L1.x, disable bit at child first, then at parent
+ * - When enabling ASPM L1.x, need to disable L1
+ * (at child followed by parent).
+ * - The ASPM/PCIPM L1.2 must be disabled while programming timin
+ * parameters
+ *
+ * To keep it simple, disable all L1SS bits first, and later enable
+ * what is needed.
+ */
+
+ /* Disable all L1 substates */
+ pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CTL1_L1SS_MASK, 0);
+ pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CTL1_L1SS_MASK, 0);
+ /*
+ * If needed, disable L1, and it gets enabled later
+ * in pcie_config_aspm_link().
+ */
+ if (enable_req & (ASPM_STATE_L1_1 | ASPM_STATE_L1_2)) {
+ pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_ASPM_L1, 0);
+ pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_ASPM_L1, 0);
+ }
+
+ if (enable_req & ASPM_STATE_L1_2_MASK) {
+
+ /* Program T_pwr_on in both ports */
+ pci_write_config_dword(parent, up_cap_ptr + PCI_L1SS_CTL2,
+ link->l1ss.ctl2);
+ pci_write_config_dword(child, dw_cap_ptr + PCI_L1SS_CTL2,
+ link->l1ss.ctl2);
+
+ /* Program T_cmn_mode in parent */
+ pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
+ 0xFF00, link->l1ss.ctl1);
+
+ /* Program LTR L1.2 threshold in both ports */
+ pci_clear_and_set_dword(parent, dw_cap_ptr + PCI_L1SS_CTL1,
+ 0xE3FF0000, link->l1ss.ctl1);
+ pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
+ 0xE3FF0000, link->l1ss.ctl1);
+ }
+
+ val = 0;
+ if (state & ASPM_STATE_L1_1)
+ val |= PCI_L1SS_CTL1_ASPM_L1_1;
+ if (state & ASPM_STATE_L1_2)
+ val |= PCI_L1SS_CTL1_ASPM_L1_2;
+ if (state & ASPM_STATE_L1_1_PCIPM)
+ val |= PCI_L1SS_CTL1_PCIPM_L1_1;
+ if (state & ASPM_STATE_L1_2_PCIPM)
+ val |= PCI_L1SS_CTL1_PCIPM_L1_2;
+
+ /* Enable what we need to enable */
+ pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CAP_L1_PM_SS, val);
+ pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CAP_L1_PM_SS, val);
+}
+
static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
{
pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
@@ -597,11 +683,23 @@ static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
{
u32 upstream = 0, dwstream = 0;
- struct pci_dev *child, *parent = link->pdev;
+ struct pci_dev *child = link->downstream, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
- /* Nothing to do if the link is already in the requested state */
+ /* Enable only the states that were not explicitly disabled */
state &= (link->aspm_capable & ~link->aspm_disable);
+
+ /* Can't enable any substates if L1 is not enabled */
+ if (!(state & ASPM_STATE_L1))
+ state &= ~ASPM_STATE_L1SS;
+
+ /* Spec says both ports must be in D0 before enabling PCI PM substates*/
+ if (parent->current_state != PCI_D0 || child->current_state != PCI_D0) {
+ state &= ~ASPM_STATE_L1_SS_PCIPM;
+ state |= (link->aspm_enabled & ASPM_STATE_L1_SS_PCIPM);
+ }
+
+ /* Nothing to do if the link is already in the requested state */
if (link->aspm_enabled == state)
return;
/* Convert ASPM state to upstream/downstream ASPM register state */
@@ -613,6 +711,10 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
upstream |= PCI_EXP_LNKCTL_ASPM_L1;
dwstream |= PCI_EXP_LNKCTL_ASPM_L1;
}
+
+ if (link->aspm_capable & ASPM_STATE_L1SS)
+ pcie_config_aspm_l1ss(link, state);
+
/*
* Spec 2.0 suggests all functions should be configured the
* same setting for ASPM. Enabling ASPM L1 should be done in
--
2.8.0.rc3.226.g39d4020
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