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PCI: rockchip: dw: Adding a retry mechanism to the enumeration process

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When there is a small probability of signal abnormality, try resetting
and enumerating again.

Change-Id: Id37950dc62a497dd1c4703c42de036ce50aaec68
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
This commit is contained in:
Jon Lin
2023-12-17 14:50:26 +08:00
committed by Tao Huang
parent 3932baf684
commit c45a42bc15
1 changed files with 82 additions and 62 deletions
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144
drivers/pci/controller/dwc/pcie-dw-rockchip.c
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@@ -109,6 +109,7 @@
#define RK_PCIE_HOTRESET_TMOUT_US 10000
#define PORT_LOGIC_LTSSM_STATE_L2(ltssm) \
((ltssm & PORT_LOGIC_LTSSM_STATE_MASK) == 0x15)
#define RK_PCIE_ENUM_HW_RETRYIES 2
#define PORT_LOGIC_LTSSM_L2
@@ -165,6 +166,8 @@ struct rk_pcie_of_data {
};
#define to_rk_pcie(x) dev_get_drvdata((x)->dev)
static int rk_pcie_disable_power(struct rk_pcie *rk_pcie);
static int rk_pcie_enable_power(struct rk_pcie *rk_pcie);
static int rk_pcie_read(void __iomem *addr, int size, u32 *val)
{
@@ -695,6 +698,8 @@ static int rk_pcie_establish_link(struct dw_pcie *pci)
int retries, power;
struct rk_pcie *rk_pcie = to_rk_pcie(pci);
bool std_rc = rk_pcie->mode == DW_PCIE_RC_TYPE && !rk_pcie->dma_obj;
int hw_retries = 0;
u32 ltssm;
/*
* For standard RC, even if the link has been setup by firmware,
@@ -706,77 +711,92 @@ static int rk_pcie_establish_link(struct dw_pcie *pci)
return 0;
}
/* Rest the device */
gpiod_set_value_cansleep(rk_pcie->rst_gpio, 0);
for (hw_retries = 0; hw_retries < RK_PCIE_ENUM_HW_RETRYIES; hw_retries++) {
/* Rest the device */
gpiod_set_value_cansleep(rk_pcie->rst_gpio, 0);
rk_pcie_disable_ltssm(rk_pcie);
rk_pcie_link_status_clear(rk_pcie);
rk_pcie_enable_debug(rk_pcie);
rk_pcie_disable_ltssm(rk_pcie);
rk_pcie_link_status_clear(rk_pcie);
rk_pcie_enable_debug(rk_pcie);
/* Enable client reset or link down interrupt */
rk_pcie_writel_apb(rk_pcie, PCIE_CLIENT_INTR_MASK, 0x40000);
/* Enable client reset or link down interrupt */
rk_pcie_writel_apb(rk_pcie, PCIE_CLIENT_INTR_MASK, 0x40000);
/* Enable LTSSM */
rk_pcie_enable_ltssm(rk_pcie);
/* Enable LTSSM */
rk_pcie_enable_ltssm(rk_pcie);
/*
* In resume routine, function devices' resume function must be late after
* controllers'. Some devices, such as Wi-Fi, need special IO setting before
* finishing training. So there must be timeout here. These kinds of devices
* need rescan devices by its driver when used. So no need to waste time waiting
* for training pass.
*/
if (rk_pcie->in_suspend && rk_pcie->skip_scan_in_resume) {
rfkill_get_wifi_power_state(&power);
if (!power) {
gpiod_set_value_cansleep(rk_pcie->rst_gpio, 1);
return 0;
}
}
/*
* PCIe requires the refclk to be stable for 100µs prior to releasing
* PERST and T_PVPERL (Power stable to PERST# inactive) should be a
* minimum of 100ms. See table 2-4 in section 2.6.2 AC, the PCI Express
* Card Electromechanical Specification 3.0. So 100ms in total is the min
* requuirement here. We add a 200ms by default for sake of hoping everthings
* work fine. If it doesn't, please add more in DT node by add rockchip,perst-inactive-ms.
*/
msleep(rk_pcie->perst_inactive_ms);
gpiod_set_value_cansleep(rk_pcie->rst_gpio, 1);
/*
* Add this 1ms delay because we observe link is always up stably after it and
* could help us save 20ms for scanning devices.
*/
usleep_range(1000, 1100);
for (retries = 0; retries < 100; retries++) {
if (dw_pcie_link_up(pci)) {
/*
* We may be here in case of L0 in Gen1. But if EP is capable
* of Gen2 or Gen3, Gen switch may happen just in this time, but
* we keep on accessing devices in unstable link status. Given
* that LTSSM max timeout is 24ms per period, we can wait a bit
* more for Gen switch.
*/
msleep(50);
/* In case link drop after linkup, double check it */
if (dw_pcie_link_up(pci)) {
dev_info(pci->dev, "PCIe Link up, LTSSM is 0x%x\n",
rk_pcie_readl_apb(rk_pcie, PCIE_CLIENT_LTSSM_STATUS));
rk_pcie_debug_dump(rk_pcie);
/*
* In resume routine, function devices' resume function must be late after
* controllers'. Some devices, such as Wi-Fi, need special IO setting before
* finishing training. So there must be timeout here. These kinds of devices
* need rescan devices by its driver when used. So no need to waste time waiting
* for training pass.
*/
if (rk_pcie->in_suspend && rk_pcie->skip_scan_in_resume) {
rfkill_get_wifi_power_state(&power);
if (!power) {
gpiod_set_value_cansleep(rk_pcie->rst_gpio, 1);
return 0;
}
}
dev_info_ratelimited(pci->dev, "PCIe Linking... LTSSM is 0x%x\n",
rk_pcie_readl_apb(rk_pcie, PCIE_CLIENT_LTSSM_STATUS));
rk_pcie_debug_dump(rk_pcie);
msleep(20);
}
/*
* PCIe requires the refclk to be stable for 100µs prior to releasing
* PERST and T_PVPERL (Power stable to PERST# inactive) should be a
* minimum of 100ms. See table 2-4 in section 2.6.2 AC, the PCI Express
* Card Electromechanical Specification 3.0. So 100ms in total is the min
* requuirement here. We add a 200ms by default for sake of hoping everthings
* work fine. If it doesn't, please add more in DT node by add rockchip,perst-inactive-ms.
*/
msleep(rk_pcie->perst_inactive_ms);
gpiod_set_value_cansleep(rk_pcie->rst_gpio, 1);
dev_err(pci->dev, "PCIe Link Fail\n");
/*
* Add this 1ms delay because we observe link is always up stably after it and
* could help us save 20ms for scanning devices.
*/
usleep_range(1000, 1100);
for (retries = 0; retries < 100; retries++) {
if (dw_pcie_link_up(pci)) {
/*
* We may be here in case of L0 in Gen1. But if EP is capable
* of Gen2 or Gen3, Gen switch may happen just in this time, but
* we keep on accessing devices in unstable link status. Given
* that LTSSM max timeout is 24ms per period, we can wait a bit
* more for Gen switch.
*/
msleep(50);
/* In case link drop after linkup, double check it */
if (dw_pcie_link_up(pci)) {
dev_info(pci->dev, "PCIe Link up, LTSSM is 0x%x\n",
rk_pcie_readl_apb(rk_pcie, PCIE_CLIENT_LTSSM_STATUS));
rk_pcie_debug_dump(rk_pcie);
return 0;
}
}
dev_info_ratelimited(pci->dev, "PCIe Linking... LTSSM is 0x%x\n",
rk_pcie_readl_apb(rk_pcie, PCIE_CLIENT_LTSSM_STATUS));
rk_pcie_debug_dump(rk_pcie);
msleep(20);
}
/*
* In response to the situation where PCIe peripherals cannot be
* enumerated due tosignal abnormalities, reset PERST# and reset
* the peripheral power supply, then restart the enumeration.
*/
ltssm = rk_pcie_readl_apb(rk_pcie, PCIE_CLIENT_LTSSM_STATUS);
dev_err(pci->dev, "PCIe Link Fail, LTSSM is 0x%x, hw_retries=%d\n", ltssm, hw_retries);
if (ltssm >= 3 && !rk_pcie->is_signal_test) {
rk_pcie_disable_power(rk_pcie);
msleep(1000);
rk_pcie_enable_power(rk_pcie);
} else {
break;
}
}
return rk_pcie->is_signal_test == true ? 0 : -EINVAL;
}