Rockchip platforms provide a 64x4 bytes debug FIFO to trace the LTSSM history. Any LTSSM change will be recorded. It's userful for debug purpose, for example link failure, etc.
Signed-off-by: Shawn Lin <[email protected]> --- Changes in v2: - use tracepoint drivers/pci/controller/dwc/pcie-dw-rockchip.c | 92 +++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c index 352f513..be9639aa 100644 --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c @@ -22,6 +22,8 @@ #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/reset.h> +#include <linux/workqueue.h> +#include <trace/events/pci_controller.h> #include "../../pci.h" #include "pcie-designware.h" @@ -73,6 +75,18 @@ #define PCIE_CLIENT_CDM_RASDES_TBA_L1_1 BIT(4) #define PCIE_CLIENT_CDM_RASDES_TBA_L1_2 BIT(5) +/* Debug FIFO information */ +#define PCIE_CLIENT_DBG_FIFO_MODE_CON 0x310 +#define PCIE_CLIENT_DBG_EN 0xffff0007 +#define PCIE_CLIENT_DBG_DIS 0xffff0000 +#define PCIE_CLIENT_DBG_FIFO_PTN_HIT_D0 0x320 +#define PCIE_CLIENT_DBG_FIFO_PTN_HIT_D1 0x324 +#define PCIE_CLIENT_DBG_FIFO_TRN_HIT_D0 0x328 +#define PCIE_CLIENT_DBG_FIFO_TRN_HIT_D1 0x32c +#define PCIE_CLIENT_DBG_TRANSITION_DATA 0xffff0000 +#define PCIE_CLIENT_DBG_FIFO_STATUS 0x350 +#define PCIE_DBG_LTSSM_HISTORY_CNT 64 + /* Hot Reset Control Register */ #define PCIE_CLIENT_HOT_RESET_CTRL 0x180 #define PCIE_LTSSM_APP_DLY2_EN BIT(1) @@ -96,6 +110,7 @@ struct rockchip_pcie { struct irq_domain *irq_domain; const struct rockchip_pcie_of_data *data; bool supports_clkreq; + struct delayed_work trace_work; }; struct rockchip_pcie_of_data { @@ -206,6 +221,79 @@ static enum dw_pcie_ltssm rockchip_pcie_get_ltssm(struct dw_pcie *pci) return rockchip_pcie_get_ltssm_reg(rockchip) & PCIE_LTSSM_STATUS_MASK; } +#ifdef CONFIG_TRACING +static void rockchip_pcie_ltssm_trace_work(struct work_struct *work) +{ + struct rockchip_pcie *rockchip = container_of(work, struct rockchip_pcie, + trace_work.work); + struct dw_pcie *pci = &rockchip->pci; + enum dw_pcie_ltssm state; + u32 val, rate, l1ss, loop, prev_val = DW_PCIE_LTSSM_UNKNOWN; + + for (loop = 0; loop < PCIE_DBG_LTSSM_HISTORY_CNT; loop++) { + val = rockchip_pcie_readl_apb(rockchip, PCIE_CLIENT_DBG_FIFO_STATUS); + rate = (val & GENMASK(22, 20)) >> 20; + l1ss = (val & GENMASK(10, 8)) >> 8; + val &= PCIE_LTSSM_STATUS_MASK; + + /* Two consecutive identical LTSSM means invalid subsequent data */ + if ((loop > 0 && val == prev_val) || val > DW_PCIE_LTSSM_RCVRY_EQ3) + break; + + state = prev_val = val; + if (val == DW_PCIE_LTSSM_L1_IDLE) { + if (l1ss == 2) + state = DW_PCIE_LTSSM_L1_2; + else if (l1ss == 1) + state = DW_PCIE_LTSSM_L1_1; + } + + trace_pcie_ltssm_state_transition(dev_name(pci->dev), + dw_pcie_ltssm_status_string(state), + ((rate + 1) > pci->max_link_speed) ? + PCI_SPEED_UNKNOWN : PCIE_SPEED_2_5GT + rate); + } + + schedule_delayed_work(&rockchip->trace_work, msecs_to_jiffies(5000)); +} + +static void rockchip_pcie_ltssm_trace(struct rockchip_pcie *rockchip, + bool en) +{ + if (en) { + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_TRANSITION_DATA, + PCIE_CLIENT_DBG_FIFO_PTN_HIT_D0); + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_TRANSITION_DATA, + PCIE_CLIENT_DBG_FIFO_PTN_HIT_D1); + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_TRANSITION_DATA, + PCIE_CLIENT_DBG_FIFO_TRN_HIT_D0); + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_TRANSITION_DATA, + PCIE_CLIENT_DBG_FIFO_TRN_HIT_D1); + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_EN, + PCIE_CLIENT_DBG_FIFO_MODE_CON); + + INIT_DELAYED_WORK(&rockchip->trace_work, + rockchip_pcie_ltssm_trace_work); + schedule_delayed_work(&rockchip->trace_work, 0); + } else { + rockchip_pcie_writel_apb(rockchip, + PCIE_CLIENT_DBG_DIS, + PCIE_CLIENT_DBG_FIFO_MODE_CON); + cancel_delayed_work_sync(&rockchip->trace_work); + } +} +#else +static void rockchip_pcie_ltssm_trace(struct rockchip_pcie *rockchip, + bool en) +{ +} +#endif + static void rockchip_pcie_enable_ltssm(struct rockchip_pcie *rockchip) { rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_ENABLE_LTSSM, @@ -289,6 +377,9 @@ static int rockchip_pcie_start_link(struct dw_pcie *pci) * 100us as we don't know how long should the device need to reset. */ msleep(PCIE_T_PVPERL_MS); + + rockchip_pcie_ltssm_trace(rockchip, true); + gpiod_set_value_cansleep(rockchip->rst_gpio, 1); return 0; @@ -299,6 +390,7 @@ static void rockchip_pcie_stop_link(struct dw_pcie *pci) struct rockchip_pcie *rockchip = to_rockchip_pcie(pci); rockchip_pcie_disable_ltssm(rockchip); + rockchip_pcie_ltssm_trace(rockchip, false); } static int rockchip_pcie_host_init(struct dw_pcie_rp *pp) -- 2.7.4
