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

If the controller is in device mode, all LSP and endpoint state
registers will be dumped. In host mode, the user must specify a LSP
register by writing to the debugfs attribute "internal_states" with the
LSP number selection.

Fixes: 80b776340c78 ("usb: dwc3: Dump LSP and BMU debug info")
Signed-off-by: Thinh Nguyen <thi...@synopsys.com>
---
 drivers/usb/dwc3/core.h    |  11 +++
 drivers/usb/dwc3/debugfs.c | 169 +++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 176 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 5bfb62533e0f..662e49ae0510 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -174,6 +174,12 @@
 #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)
@@ -253,6 +259,9 @@
 #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)
@@ -945,6 +954,7 @@ struct dwc3_scratchpad_array {
  * @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
@@ -1120,6 +1130,7 @@ struct dwc3 {
        struct dwc3_hwparams    hwparams;
        struct dentry           *root;
        struct debugfs_regset32 *regset;
+       int                     dbg_lsp_select;
 
        u8                      test_mode;
        u8                      test_mode_nr;
diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
index df8e73ec3342..cf3c95838a96 100644
--- a/drivers/usb/dwc3/debugfs.c
+++ b/drivers/usb/dwc3/debugfs.c
@@ -25,6 +25,8 @@
 #include "io.h"
 #include "debug.h"
 
+#define DWC3_LSP_MUX_UNSELECTED 0xfffff
+
 #define dump_register(nm)                              \
 {                                                      \
        .name   = __stringify(nm),                      \
@@ -82,10 +84,6 @@ static const struct debugfs_reg32 dwc3_regs[] = {
        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),
@@ -279,6 +277,164 @@ static const struct debugfs_reg32 dwc3_regs[] = {
        dump_register(OSTS),
 };
 
+static u32 dwc3_host_lsp_register(struct dwc3 *dwc, bool is_dbc, int select)
+{
+       unsigned long           flags;
+       u32                     reg;
+
+       reg = DWC3_GDBGLSPMUX_HOSTSELECT(select);
+
+       if (is_dbc)
+               reg |= DWC3_GDBGLSPMUX_ENDBC;
+
+       spin_lock_irqsave(&dwc->lock, flags);
+       dwc3_writel(dwc->regs, DWC3_GDBGLSPMUX, reg);
+       reg = dwc3_readl(dwc->regs, DWC3_GDBGLSP);
+       spin_unlock_irqrestore(&dwc->lock, flags);
+
+       return reg;
+}
+
+static u32 dwc3_gadget_lsp_register(struct dwc3 *dwc, int select)
+{
+       unsigned long           flags;
+       u32                     reg;
+
+       reg = DWC3_GDBGLSPMUX_DEVSELECT(select);
+
+       spin_lock_irqsave(&dwc->lock, flags);
+       dwc3_writel(dwc->regs, DWC3_GDBGLSPMUX, reg);
+       reg = dwc3_readl(dwc->regs, DWC3_GDBGLSP);
+       spin_unlock_irqrestore(&dwc->lock, flags);
+
+       return reg;
+}
+
+static u64 dwc3_ep_info_register(struct dwc3 *dwc, int select)
+{
+       unsigned long           flags;
+       u64                     ep_info;
+       u32                     lower_32_bits;
+       u32                     upper_32_bits;
+       u32                     reg;
+
+       reg = DWC3_GDBGLSPMUX_EPSELECT(select);
+
+       spin_lock_irqsave(&dwc->lock, flags);
+       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);
+       spin_unlock_irqrestore(&dwc->lock, flags);
+
+       ep_info = ((u64)upper_32_bits << 32) | lower_32_bits;
+
+       return ep_info;
+}
+
+static void dwc3_dump_host_internal_states(struct seq_file *s)
+{
+       struct dwc3             *dwc = s->private;
+       int                     sel;
+       u32                     reg;
+
+       sel = dwc->dbg_lsp_select;
+
+       if (sel == DWC3_LSP_MUX_UNSELECTED) {
+               seq_printf(s, "No LSP MUX selection\n");
+               return;
+       }
+
+       reg = dwc3_host_lsp_register(dwc, false, sel);
+       seq_printf(s, "GDBGLSP[%d] = 0x%08x\n", sel, reg);
+
+       reg = dwc3_host_lsp_register(dwc, true, sel);
+       seq_printf(s, "GDBGLSP_DBC[%d] = 0x%08x\n", sel, reg);
+}
+
+static void dwc3_dump_gadget_internal_states(struct seq_file *s)
+{
+       struct dwc3             *dwc = s->private;
+       int                     num_selects = 16;
+       int                     i;
+       u32                     reg;
+       u64                     ep_info;
+
+       for (i = 0; i < num_selects; i++) {
+               reg = dwc3_gadget_lsp_register(dwc, i);
+               seq_printf(s, "GDBGLSP[%d] = 0x%08x\n", i, reg);
+       }
+
+       for (i = 0; i < dwc->num_eps; i++) {
+               ep_info = dwc3_ep_info_register(dwc, i);
+               seq_printf(s, "GDBGEPINFO[%d] = 0x%016llx\n", i, ep_info);
+       }
+}
+
+static int dwc3_internal_states_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);
+
+       reg = dwc3_readl(dwc->regs, DWC3_GDBGBMU);
+       spin_unlock_irqrestore(&dwc->lock, flags);
+
+       seq_printf(s, "GDBGBMU = 0x%08x\n", reg);
+
+       switch (current_mode) {
+       case DWC3_GSTS_CURMOD_HOST:
+               dwc3_dump_host_internal_states(s);
+               break;
+       case DWC3_GSTS_CURMOD_DEVICE:
+               dwc3_dump_gadget_internal_states(s);
+               break;
+       default:
+               seq_printf(s, "Mode is unknown, no LSP register printed\n");
+               break;
+       }
+
+       return 0;
+}
+
+static int dwc3_internal_states_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, dwc3_internal_states_show, inode->i_private);
+}
+
+static ssize_t dwc3_internal_states_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;
+       char                    buf[32] = { 0 };
+       int                     sel;
+       int                     ret;
+
+       if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+               return -EFAULT;
+
+       ret = kstrtoint(buf, 0, &sel);
+       if (ret)
+               return ret;
+
+       dwc->dbg_lsp_select = sel;
+
+       return count;
+}
+
+static const struct file_operations dwc3_internal_states_fops = {
+       .open                   = dwc3_internal_states_open,
+       .write                  = dwc3_internal_states_write,
+       .read                   = seq_read,
+       .llseek                 = seq_lseek,
+       .release                = single_release,
+};
+
 static int dwc3_mode_show(struct seq_file *s, void *unused)
 {
        struct dwc3             *dwc = s->private;
@@ -742,6 +898,8 @@ void dwc3_debugfs_init(struct dwc3 *dwc)
        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;
@@ -751,6 +909,9 @@ void dwc3_debugfs_init(struct dwc3 *dwc)
 
        debugfs_create_regset32("regdump", S_IRUGO, root, dwc->regset);
 
+       debugfs_create_file("internal_states", S_IRUGO | S_IWUSR, root, dwc,
+                           &dwc3_internal_states_fops);
+
        if (IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)) {
                debugfs_create_file("mode", S_IRUGO | S_IWUSR, root, dwc,
                                    &dwc3_mode_fops);
-- 
2.11.0

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