usb: dwc3: debugfs: Dump internal LSP and ep registers

To dump internal LSP and endpoint state debug registers, we must write
to GDBGLSPMUX register. This patch correctly dump LSP and endpoint
states from the debug registers.

If the controller is in device mode, all LSP and endpoint state
registers will be dumped via the debugfs attribute "lsp_dump". In host
mode, the user has to write the LSP number to "lsp_dump" to dump a
specific LSP selection.

Fixes: 80b776340c78 ("usb: dwc3: Dump LSP and BMU debug info")
Signed-off-by: Thinh Nguyen <[e-mail]>
Signed-off-by: Felipe Balbi <[e-mail]>

drivers/usb/dwc3/core.h

···
 #define DWC3_GSBUSCFG0_INCRBRSTENA	(1 << 0) /* undefined length enable */
 #define DWC3_GSBUSCFG0_INCRBRST_MASK	0xff
 
+/* Global Debug LSP MUX Select */
+#define DWC3_GDBGLSPMUX_ENDBC		BIT(15)	/* Host only */
+#define DWC3_GDBGLSPMUX_HOSTSELECT(n)	((n) & 0x3fff)
+#define DWC3_GDBGLSPMUX_DEVSELECT(n)	(((n) & 0xf) << 4)
+#define DWC3_GDBGLSPMUX_EPSELECT(n)	((n) & 0xf)
+
 /* Global Debug Queue/FIFO Space Available Register */
 #define DWC3_GDBGFIFOSPACE_NUM(n)	((n) & 0x1f)
 #define DWC3_GDBGFIFOSPACE_TYPE(n)	(((n) << 5) & 0x1e0)
···
 #define DWC3_GSTS_DEVICE_IP	BIT(6)
 #define DWC3_GSTS_CSR_TIMEOUT	BIT(5)
 #define DWC3_GSTS_BUS_ERR_ADDR_VLD	BIT(4)
+#define DWC3_GSTS_CURMOD(n)	((n) & 0x3)
+#define DWC3_GSTS_CURMOD_DEVICE	0
+#define DWC3_GSTS_CURMOD_HOST	1
 
 /* Global USB2 PHY Configuration Register */
 #define DWC3_GUSB2PHYCFG_PHYSOFTRST	BIT(31)
···
 #define DWC3_GHWPARAMS1_EN_PWROPT_HIB	2
 #define DWC3_GHWPARAMS1_PWROPT(n)	((n) << 24)
 #define DWC3_GHWPARAMS1_PWROPT_MASK	DWC3_GHWPARAMS1_PWROPT(3)
+#define DWC3_GHWPARAMS1_ENDBC		BIT(31)
 
 /* Global HWPARAMS3 Register */
 #define DWC3_GHWPARAMS3_SSPHY_IFC(n)		((n) & 3)
···
  * @hwparams: copy of hwparams registers
  * @root: debugfs root folder pointer
  * @regset: debugfs pointer to regdump file
+ * @dbg_lsp_select: current debug lsp mux register selection
  * @test_mode: true when we're entering a USB test mode
  * @test_mode_nr: test feature selector
  * @lpm_nyet_threshold: LPM NYET response threshold
···
 	struct dwc3_hwparams	hwparams;
 	struct dentry		*root;
 	struct debugfs_regset32	*regset;
+
+	u32			dbg_lsp_select;
 
 	u8			test_mode;
 	u8			test_mode_nr;

drivers/usb/dwc3/debugfs.c

···
 #include "io.h"
 #include "debug.h"
 
+#define DWC3_LSP_MUX_UNSELECTED 0xfffff
+
 #define dump_register(nm)				\
 {							\
 	.name	= __stringify(nm),			\
···
 	dump_register(GDBGFIFOSPACE),
 	dump_register(GDBGLTSSM),
 	dump_register(GDBGBMU),
-	dump_register(GDBGLSPMUX),
-	dump_register(GDBGLSP),
-	dump_register(GDBGEPINFO0),
-	dump_register(GDBGEPINFO1),
 	dump_register(GPRTBIMAP_HS0),
 	dump_register(GPRTBIMAP_HS1),
 	dump_register(GPRTBIMAP_FS0),
···
 	dump_register(OEVT),
 	dump_register(OEVTEN),
 	dump_register(OSTS),
+};
+
+static void dwc3_host_lsp(struct seq_file *s)
+{
+	struct dwc3		*dwc = s->private;
+	bool			dbc_enabled;
+	u32			sel;
+	u32			reg;
+	u32			val;
+
+	dbc_enabled = !!(dwc->hwparams.hwparams1 & DWC3_GHWPARAMS1_ENDBC);
+
+	sel = dwc->dbg_lsp_select;
+	if (sel == DWC3_LSP_MUX_UNSELECTED) {
+		seq_puts(s, "Write LSP selection to print for host\n");
+		return;
+	}
+
+	reg = DWC3_GDBGLSPMUX_HOSTSELECT(sel);
+
+	dwc3_writel(dwc->regs, DWC3_GDBGLSPMUX, reg);
+	val = dwc3_readl(dwc->regs, DWC3_GDBGLSP);
+	seq_printf(s, "GDBGLSP[%d] = 0x%08x\n", sel, val);
+
+	if (dbc_enabled && sel < 256) {
+		reg |= DWC3_GDBGLSPMUX_ENDBC;
+		dwc3_writel(dwc->regs, DWC3_GDBGLSPMUX, reg);
+		val = dwc3_readl(dwc->regs, DWC3_GDBGLSP);
+		seq_printf(s, "GDBGLSP_DBC[%d] = 0x%08x\n", sel, val);
+	}
+}
+
+static void dwc3_gadget_lsp(struct seq_file *s)
+{
+	struct dwc3		*dwc = s->private;
+	int			i;
+	u32			reg;
+
+	for (i = 0; i < 16; i++) {
+		reg = DWC3_GDBGLSPMUX_DEVSELECT(i);
+		dwc3_writel(dwc->regs, DWC3_GDBGLSPMUX, reg);
+		reg = dwc3_readl(dwc->regs, DWC3_GDBGLSP);
+		seq_printf(s, "GDBGLSP[%d] = 0x%08x\n", i, reg);
+	}
+}
+
+static int dwc3_lsp_show(struct seq_file *s, void *unused)
+{
+	struct dwc3		*dwc = s->private;
+	unsigned int		current_mode;
+	unsigned long		flags;
+	u32			reg;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	reg = dwc3_readl(dwc->regs, DWC3_GSTS);
+	current_mode = DWC3_GSTS_CURMOD(reg);
+
+	switch (current_mode) {
+	case DWC3_GSTS_CURMOD_HOST:
+		dwc3_host_lsp(s);
+		break;
+	case DWC3_GSTS_CURMOD_DEVICE:
+		dwc3_gadget_lsp(s);
+		break;
+	default:
+		seq_puts(s, "Mode is unknown, no LSP register printed\n");
+		break;
+	}
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	return 0;
+}
+
+static int dwc3_lsp_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, dwc3_lsp_show, inode->i_private);
+}
+
+static ssize_t dwc3_lsp_write(struct file *file, const char __user *ubuf,
+			      size_t count, loff_t *ppos)
+{
+	struct seq_file		*s = file->private_data;
+	struct dwc3		*dwc = s->private;
+	unsigned long		flags;
+	char			buf[32] = { 0 };
+	u32			sel;
+	int			ret;
+
+	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+		return -EFAULT;
+
+	ret = kstrtouint(buf, 0, &sel);
+	if (ret)
+		return ret;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	dwc->dbg_lsp_select = sel;
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	return count;
+}
+
+static const struct file_operations dwc3_lsp_fops = {
+	.open			= dwc3_lsp_open,
+	.write			= dwc3_lsp_write,
+	.read			= seq_read,
+	.llseek			= seq_lseek,
+	.release		= single_release,
 };
 
 static int dwc3_mode_show(struct seq_file *s, void *unused)
···
 	return 0;
 }
 
+static int dwc3_ep_info_register_show(struct seq_file *s, void *unused)
+{
+	struct dwc3_ep		*dep = s->private;
+	struct dwc3		*dwc = dep->dwc;
+	unsigned long		flags;
+	u64			ep_info;
+	u32			lower_32_bits;
+	u32			upper_32_bits;
+	u32			reg;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	reg = DWC3_GDBGLSPMUX_EPSELECT(dep->number);
+	dwc3_writel(dwc->regs, DWC3_GDBGLSPMUX, reg);
+
+	lower_32_bits = dwc3_readl(dwc->regs, DWC3_GDBGEPINFO0);
+	upper_32_bits = dwc3_readl(dwc->regs, DWC3_GDBGEPINFO1);
+
+	ep_info = ((u64)upper_32_bits << 32) | lower_32_bits;
+	seq_printf(s, "0x%016llx\n", ep_info);
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	return 0;
+}
+
 DEFINE_SHOW_ATTRIBUTE(dwc3_tx_fifo_size);
 DEFINE_SHOW_ATTRIBUTE(dwc3_rx_fifo_size);
 DEFINE_SHOW_ATTRIBUTE(dwc3_tx_request_queue);
···
 DEFINE_SHOW_ATTRIBUTE(dwc3_event_queue);
 DEFINE_SHOW_ATTRIBUTE(dwc3_transfer_type);
 DEFINE_SHOW_ATTRIBUTE(dwc3_trb_ring);
+DEFINE_SHOW_ATTRIBUTE(dwc3_ep_info_register);
 
 static const struct dwc3_ep_file_map dwc3_ep_file_map[] = {
 	{ "tx_fifo_size", &dwc3_tx_fifo_size_fops, },
···
 	{ "event_queue", &dwc3_event_queue_fops, },
 	{ "transfer_type", &dwc3_transfer_type_fops, },
 	{ "trb_ring", &dwc3_trb_ring_fops, },
+	{ "GDBGEPINFO", &dwc3_ep_info_register_fops, },
 };
 
 static void dwc3_debugfs_create_endpoint_files(struct dwc3_ep *dep,
···
 	if (!dwc->regset)
 		return;
 
+	dwc->dbg_lsp_select = DWC3_LSP_MUX_UNSELECTED;
+
 	dwc->regset->regs = dwc3_regs;
 	dwc->regset->nregs = ARRAY_SIZE(dwc3_regs);
 	dwc->regset->base = dwc->regs - DWC3_GLOBALS_REGS_START;
···
 	dwc->root = root;
 
 	debugfs_create_regset32("regdump", S_IRUGO, root, dwc->regset);
+
+	debugfs_create_file("lsp_dump", S_IRUGO | S_IWUSR, root, dwc,
+			    &dwc3_lsp_fops);
 
 	if (IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)) {
 		debugfs_create_file("mode", S_IRUGO | S_IWUSR, root, dwc,