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pci: msm: Add API to control pcie link state of NTN3 downstream port

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On CPE platform, there is ntn3 pcie switch locates between RC and
Wlan, so the wlan pcie link is separated two parts, RC<->USP and
DSP<->WLAN, when pcie link suspend/resume, the link status of these
two buses is different, when link suspend the RC<->USP is not powered
off due to the existence of Ethernet device under same pcie switch.
For the case of cnss driver to power on/off wlan soc when pcie link
is still turned on, to avoid AER issue, before power on wlan soc cnss
driver needs to disable DSP<->WLAN link and then enable the link and
wait for link training completion Before powering off wlan soc cnss
driver also needs to disable DSP<->WLAN link at first. Function
msm_pcie_ntn3_dsp_link_control() is called by cnss driver to
enable(with link train)/disable DSP<->WLAN link when RC<->USP is on.

Change-Id: I8236b0786a14d6fb6c11805f24407edaa24e9836
Signed-off-by: Harrison Meng <quic_hmeng@quicinc.com>
Signed-off-by: Yogesh Jadav <quic_yjadav@quicinc.com>
Signed-off-by: Joco Zhang <quic_pingshen@quicinc.com>
This commit is contained in:
Harrison Meng 2022-04-19 22:49:48 -07:00 committed by Joco Zhang
parent caf2e99f0c
commit 3fcfd9ecc2
2 changed files with 99 additions and 0 deletions
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82
drivers/pci/controller/pci-msm.c
View File

@ -8979,6 +8979,88 @@ static int msm_pcie_set_link_width(struct msm_pcie_dev_t *pcie_dev,
return -EINVAL;
}
int msm_pcie_dsp_link_control(struct pci_dev *pci_dev,
bool link_enable)
{
int ret = 0;
struct pci_dev *dsp_dev = NULL;
u16 link_control = 0;
u16 link_status = 0;
u32 link_capability = 0;
int link_check_count = 0;
bool link_trained = false;
struct msm_pcie_dev_t *pcie_dev = PCIE_BUS_PRIV_DATA(pci_dev->bus);
if (!pcie_dev->power_on)
return 0;
dsp_dev = pci_dev->bus->self;
if (pci_pcie_type(dsp_dev) != PCI_EXP_TYPE_DOWNSTREAM) {
PCIE_DBG(pcie_dev,
"PCIe: RC%d: no DSP<->EP link under this RC\n",
pcie_dev->rc_idx);
return 0;
}
pci_read_config_dword(dsp_dev, dsp_dev->pcie_cap + PCI_EXP_LNKCAP,
&link_capability);
pci_read_config_word(dsp_dev, dsp_dev->pcie_cap + PCI_EXP_LNKCTL,
&link_control);
if (link_enable) {
link_control &= ~PCI_EXP_LNKCTL_LD;
pci_write_config_word(dsp_dev,
dsp_dev->pcie_cap + PCI_EXP_LNKCTL,
link_control);
PCIE_DBG(pcie_dev,
"PCIe: RC%d: DSP<->EP Link is enabled\n",
pcie_dev->rc_idx);
/* Wait for up to 100ms for the link to come up */
do {
usleep_range(LINK_UP_TIMEOUT_US_MIN,
LINK_UP_TIMEOUT_US_MAX);
pci_read_config_word(dsp_dev,
dsp_dev->pcie_cap + PCI_EXP_LNKSTA,
&link_status);
if (link_capability & PCI_EXP_LNKCAP_DLLLARC)
link_trained = (!(link_status &
PCI_EXP_LNKSTA_LT)) &&
(link_status &
PCI_EXP_LNKSTA_DLLLA);
else
link_trained = !(link_status &
PCI_EXP_LNKSTA_LT);
if (link_trained)
break;
} while (link_check_count++ < LINK_UP_CHECK_MAX_COUNT);
if (link_trained) {
PCIE_DBG(pcie_dev,
"PCIe: RC%d: DSP<->EP link status: 0x%04x\n",
pcie_dev->rc_idx, link_status);
PCIE_DBG(pcie_dev,
"PCIe: RC%d: DSP<->EP Link is up after %d checkings\n",
pcie_dev->rc_idx, link_check_count);
} else {
PCIE_DBG(pcie_dev, "DSP<->EP link initialization failed\n");
ret = MSM_PCIE_ERROR;
}
} else {
link_control |= PCI_EXP_LNKCTL_LD;
pci_write_config_word(dsp_dev,
dsp_dev->pcie_cap + PCI_EXP_LNKCTL,
link_control);
PCIE_DBG(pcie_dev,
"PCIe: RC%d: DSP<->EP Link is disabled\n",
pcie_dev->rc_idx);
}
return ret;
}
EXPORT_SYMBOL_GPL(msm_pcie_dsp_link_control);
void msm_pcie_allow_l1(struct pci_dev *pci_dev)
{
struct pci_dev *root_pci_dev;

17
include/linux/msm_pcie.h
View File

@ -225,6 +225,17 @@ int msm_pcie_debug_info(struct pci_dev *dev, u32 option, u32 base,
*/
int msm_pcie_reg_dump(struct pci_dev *pci_dev, u8 *buff, u32 len);
/*
* msm_pcie_dsp_link_control - enable/disable DSP link
* @pci_dev: pci device structure, endpoint of this DSP
* @link_enable true to enable, false to disable
*
* This function enable(include training)/disable link between PCIe
* switch DSP and endpoint attached.
* Return: 0 on success, negative value on error
*/
int msm_pcie_dsp_link_control(struct pci_dev *pci_dev,
bool link_enable);
#else /* !CONFIG_PCI_MSM */
static inline int msm_pcie_pm_control(enum msm_pcie_pm_opt pm_opt, u32 busnr,
void *user, void *data, u32 options)
@ -287,6 +298,12 @@ static inline int msm_pcie_reg_dump(struct pci_dev *pci_dev, u8 *buff, u32 len)
{
return -ENODEV;
}
static inline int msm_pcie_dsp_link_control(struct pci_dev *pci_dev,
bool link_enable)
{
return -ENODEV;
}
#endif /* CONFIG_PCI_MSM */
#endif /* __MSM_PCIE_H */