Add support to dump LTSSM trace through a port specific debugfs entry
'ltssm_trace'. This is particular useful to debug link up issues and
speed change issues. Trace is dumped in the following format.
[root@alarm ~]# cat /sys/kernel/debug/pcie/0/ltssm_trace
Trace Reg Val Major Minor-Tx Minor-Rx
----------------------------------------------------
[0x00090824] detect active active
[0x001b0864] detect wait wait
[0x001208a4] detect retry retry
[0x000018e4] polling active active
[0x00091924] polling config config
[0x00002964] config link start link start
[0x000929a4] config link accept link accept
[0x001b29e4] config lane wait lane wait
[0x00122a24] config lane accept lane accept
[0x00362a64] config complete complete
[0x00242aa4] config idle idle
[0x00004ae4] l0 normal normal
[0x00054b24] l0 pwrup normal
[0x00387b64] recovery rcvrlock finish pkt
[0x00007ba4] recovery rcvrlock rcvrlock
[0x00097be4] recovery rcvrcfg rcvrcfg
[0x001b7c24] recovery idle idle
[0x00004c64] l0 normal normal
Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
---
drivers/pci/controller/pci-tegra.c | 201 +++++++++++++++++++++++++++++
1 file changed, 201 insertions(+)
diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
index 464ba2538d52..2b5b43e09ced 100644
--- a/drivers/pci/controller/pci-tegra.c
+++ b/drivers/pci/controller/pci-tegra.c
@@ -177,6 +177,26 @@
#define AFI_PEXBIAS_CTRL_0 0x168
+#define RP_LTSSM_DBGREG 0xe44
+#define RP_LTSSM_DBGREG_LINKFSM16 BIT(16)
+
+#define RP_LTSSM_TRACE_CTRL 0xe50
+#define LTSSM_TRACE_CTRL_CLEAR_STORE_EN BIT(0)
+#define LTSSM_TRACE_CTRL_CLEAR_RAM BIT(2)
+#define LTSSM_TRACE_CTRL_TRIG_ON_EVENT BIT(3)
+#define LTSSM_TRACE_CTRL_TRIG_LTSSM_MAJOR_OFFSET 4
+#define LTSSM_TRACE_CTRL_TRIG_PTX_LTSSM_MINOR_OFFSET 8
+#define LTSSM_TRACE_CTRL_TRIG_PRX_LTSSM_MAJOR_OFFSET 11
+
+#define RP_LTSSM_TRACE_STS 0xe54
+#define LTSSM_TRACE_STS_PRX_MINOR(reg) (((reg) >> 19) & 0x7)
+#define LTSSM_TRACE_STS_PTX_MINOR(reg) (((reg) >> 16) & 0x7)
+#define LTSSM_TRACE_STS_MAJOR(reg) (((reg) >> 12) & 0xf)
+#define LTSSM_TRACE_STS_READ_DATA_VALID(reg) (((reg) >> 11) & 0x1)
+#define LTSSM_TRACE_STS_READ_ADDR(reg) ((reg) << 6)
+#define LTSSM_TRACE_STS_WRITE_POINTER(reg) (((reg) >> 1) & 0x1f)
+#define LTSSM_TRACE_STS_RAM_FULL(reg) ((reg) & 0x1)
+
#define RP_VEND_XP 0x00000f00
#define RP_VEND_XP_DL_UP (1 << 30)
@@ -321,6 +341,7 @@ struct tegra_pcie_port {
unsigned int lanes;
struct phy **phys;
+ struct dentry *debugfs;
};
struct tegra_pcie_bus {
@@ -2348,9 +2369,184 @@ static void tegra_pcie_debugfs_exit(struct tegra_pcie *pcie)
pcie->debugfs = NULL;
}
+struct ltssm_major_state {
+ const char *name;
+ const char *minor[8];
+};
+
+struct ltssm_state {
+ struct ltssm_major_state major[12];
+};
+
+static const struct ltssm_state ltssm_state = {
+ .major = {
+ {
+ .name = "detect",
+ .minor = {"quiet",
+ "active",
+ "retry",
+ "wait",
+ "entry"}
+ }, {
+ .name = "polling",
+ .minor = {"active",
+ "config",
+ "idle",
+ NULL,
+ "compliance",
+ "cspeed"}
+ }, {
+ .name = "config",
+ .minor = {"link start",
+ "link accept",
+ "lane accept",
+ "lane wait",
+ "idle",
+ "pwrup",
+ "complete"}
+ }, {
+ .name = NULL,
+ .minor = {NULL}
+ }, {
+ .name = "l0",
+ .minor = {"normal",
+ "l0s entry",
+ "l0s idle",
+ "l0s wait",
+ "l0s fts",
+ "pwrup"}
+ }, {
+ .name = "l1",
+ .minor = {"entry",
+ "waitrx",
+ "idle",
+ "wait",
+ "pwrup",
+ "beacon entry",
+ "beacon exit"}
+ }, {
+ .name = "l2",
+ .minor = {"entry",
+ "waitrx",
+ "transmitwake",
+ "idle"}
+ }, {
+ .name = "recovery",
+ .minor = {"rcvrlock",
+ "rcvrcfg",
+ "speed",
+ "idle",
+ NULL,
+ NULL,
+ NULL,
+ "finish pkt"}
+ }, {
+ .name = "loopback",
+ .minor = {"entry",
+ "active",
+ "idle",
+ "exit",
+ "speed",
+ "pre speed"}
+ }, {
+ .name = "hotreset",
+ .minor = {NULL}
+ }, {
+ .name = "disabled",
+ .minor = {NULL}
+ }, {
+ .name = "txchar",
+ .minor = {NULL}
+ }
+ }
+};
+
+static const char *ltssm_get_major(unsigned int major)
+{
+ const char *state;
+
+ state = ltssm_state.major[major].name;
+ if (!state)
+ return "unknown";
+
+ return state;
+}
+
+static const char *ltssm_get_minor(unsigned int major, unsigned int minor)
+{
+ const char *state;
+
+ state = ltssm_state.major[major].minor[minor];
+ if (!state)
+ return "unknown";
+
+ return state;
+}
+
+static int ltssm_trace_show(struct seq_file *s, void *what)
+{
+ struct tegra_pcie_port *port = s->private;
+ unsigned int ridx, widx, entries;
+ u32 value;
+
+ value = readl(port->base + RP_LTSSM_TRACE_STS);
+ widx = LTSSM_TRACE_STS_WRITE_POINTER(value);
+ entries = LTSSM_TRACE_STS_RAM_FULL(value) ? 32 : widx;
+
+ seq_puts(s, "Trace Reg Val Major Minor-Tx Minor-Rx\n");
+ seq_puts(s, "----------------------------------------------------\n");
+ for (ridx = 0; ridx < entries; ridx++) {
+ value = LTSSM_TRACE_STS_READ_ADDR(ridx);
+ writel(value, port->base + RP_LTSSM_TRACE_STS);
+ value = readl(port->base + RP_LTSSM_TRACE_STS);
+
+ seq_printf(s, "[0x%08x] %-10s %-13s %s\n", value,
+ ltssm_get_major(LTSSM_TRACE_STS_MAJOR(value)),
+ ltssm_get_minor(LTSSM_TRACE_STS_MAJOR(value),
+ LTSSM_TRACE_STS_PTX_MINOR(value)),
+ ltssm_get_minor(LTSSM_TRACE_STS_MAJOR(value),
+ LTSSM_TRACE_STS_PRX_MINOR(value)));
+ }
+
+ /* Clear Trace RAM */
+ value = readl(port->base + RP_LTSSM_TRACE_CTRL);
+ value |= LTSSM_TRACE_CTRL_CLEAR_RAM;
+ writel(value, port->base + RP_LTSSM_TRACE_CTRL);
+ value &= ~LTSSM_TRACE_CTRL_CLEAR_RAM;
+ writel(value, port->base + RP_LTSSM_TRACE_CTRL);
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ltssm_trace);
+
+static int tegra_pcie_port_debugfs_init(struct tegra_pcie_port *port)
+{
+ struct dentry *d;
+ char port_name[2] = {0};
+
+ snprintf(port_name, sizeof(port_name), "%d", port->index);
+ port->debugfs = debugfs_create_dir(port_name,
+ port->pcie->debugfs);
+ if (!port->debugfs)
+ return -ENOMEM;
+
+ d = debugfs_create_file("ltssm_trace", 0444, port->debugfs, port,
+ <ssm_trace_fops);
+ if (!d)
+ goto remove;
+
+ return 0;
+
+remove:
+ debugfs_remove_recursive(port->debugfs);
+ port->debugfs = NULL;
+ return -ENOMEM;
+}
+
static int tegra_pcie_debugfs_init(struct tegra_pcie *pcie)
{
struct dentry *file;
+ struct tegra_pcie_port *port;
pcie->debugfs = debugfs_create_dir("pcie", NULL);
if (!pcie->debugfs)
@@ -2361,6 +2557,11 @@ static int tegra_pcie_debugfs_init(struct tegra_pcie *pcie)
if (!file)
goto remove;
+ list_for_each_entry(port, &pcie->ports, list) {
+ if (tegra_pcie_port_debugfs_init(port))
+ goto remove;
+ }
+
return 0;
remove:
--
2.17.1
