[PATCH v6 1/3] debugfs_create_regset32() support 8/16 bit width registers

From: Frank Li
Date: Tue Oct 03 2023 - 10:54:49 EST


Enhance the flexibility of `debugfs_create_regset32()` to support registers
of various bit widths. The key changes are as follows:

1. Renamed '*reg32' and '*regset32' to '*reg' and '*regset' in relevant
code to reflect that the register width is not limited to 32 bits.

2. Added 'size' and 'bigendian' fields to the `struct debugfs_reg` to allow
for specifying the size and endianness of registers. These additions
enable `debugfs_create_regset()` to support a wider range of register
types.

3. When 'size' is set to 0, it signifies a 32-bit register. This change
maintains compatibility with existing code that assumes 32-bit
registers.

Improve the versatility of `debugfs_create_regset()` and enable it to
handle registers of different sizes and endianness, offering greater
flexibility for debugging and monitoring.

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
fs/debugfs/file.c | 54 +++++++++++++++++++++++++++--------------
include/linux/debugfs.h | 17 ++++++++++---
2 files changed, 49 insertions(+), 22 deletions(-)

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 87b3753aa4b1..2f2baf5ee3b3 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -1137,15 +1137,15 @@ EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
#ifdef CONFIG_HAS_IOMEM

/*
- * The regset32 stuff is used to print 32-bit registers using the
+ * The regset stuff is used to print 32-bit registers using the
* seq_file utilities. We offer printing a register set in an already-opened
- * sequential file or create a debugfs file that only prints a regset32.
+ * sequential file or create a debugfs file that only prints a regset.
*/

/**
- * debugfs_print_regs32 - use seq_print to describe a set of registers
+ * debugfs_print_regs - use seq_print to describe a set of registers
* @s: the seq_file structure being used to generate output
- * @regs: an array if struct debugfs_reg32 structures
+ * @regs: an array if struct debugfs_reg structures
* @nregs: the length of the above array
* @base: the base address to be used in reading the registers
* @prefix: a string to be prefixed to every output line
@@ -1157,30 +1157,48 @@ EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
* because some peripherals have several blocks of identical registers,
* for example configuration of dma channels
*/
-void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
+void debugfs_print_regs(struct seq_file *s, const struct debugfs_reg *regs,
int nregs, void __iomem *base, char *prefix)
{
+ void __iomem *reg;
+ bool b;
int i;

for (i = 0; i < nregs; i++, regs++) {
if (prefix)
seq_printf(s, "%s", prefix);
- seq_printf(s, "%s = 0x%08x\n", regs->name,
- readl(base + regs->offset));
+
+ b = regs->bigendian;
+ reg = base + regs->offset;
+
+ switch (regs->size) {
+ case sizeof(u8):
+ seq_printf(s, "%s = 0x%02x\n", regs->name, ioread8(reg));
+ break;
+ case sizeof(u16):
+ seq_printf(s, "%s = 0x%04x\n", regs->name,
+ b ? ioread16be(reg) : ioread16(reg));
+ break;
+ case sizeof(u32):
+ case 0:
+ seq_printf(s, "%s = 0x%08x\n", regs->name,
+ b ? ioread32be(reg) : ioread32(reg));
+ }
+
if (seq_has_overflowed(s))
break;
}
}
-EXPORT_SYMBOL_GPL(debugfs_print_regs32);
+EXPORT_SYMBOL_GPL(debugfs_print_regs);

-static int debugfs_regset32_show(struct seq_file *s, void *data)
+static int debugfs_regset_show(struct seq_file *s, void *data)
{
- struct debugfs_regset32 *regset = s->private;
+ struct debugfs_regset *regset = s->private;

if (regset->dev)
pm_runtime_get_sync(regset->dev);

- debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
+ debugfs_print_regs(s, regset->regs, regset->nregs, regset->base, "");

if (regset->dev)
pm_runtime_put(regset->dev);
@@ -1188,16 +1206,16 @@ static int debugfs_regset32_show(struct seq_file *s, void *data)
return 0;
}

-DEFINE_SHOW_ATTRIBUTE(debugfs_regset32);
+DEFINE_SHOW_ATTRIBUTE(debugfs_regset);

/**
- * debugfs_create_regset32 - create a debugfs file that returns register values
+ * debugfs_create_regset - create a debugfs file that returns register values
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
- * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
+ * @regset: a pointer to a struct debugfs_regset, which contains a pointer
* to an array of register definitions, the array size and the base
* address where the register bank is to be found.
*
@@ -1205,13 +1223,13 @@ DEFINE_SHOW_ATTRIBUTE(debugfs_regset32);
* the names and values of a set of 32-bit registers. If the @mode variable
* is so set it can be read from. Writing is not supported.
*/
-void debugfs_create_regset32(const char *name, umode_t mode,
+void debugfs_create_regset(const char *name, umode_t mode,
struct dentry *parent,
- struct debugfs_regset32 *regset)
+ struct debugfs_regset *regset)
{
- debugfs_create_file(name, mode, parent, regset, &debugfs_regset32_fops);
+ debugfs_create_file(name, mode, parent, regset, &debugfs_regset_fops);
}
-EXPORT_SYMBOL_GPL(debugfs_create_regset32);
+EXPORT_SYMBOL_GPL(debugfs_create_regset);

#endif /* CONFIG_HAS_IOMEM */

diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index ea2d919fd9c7..247ae4217ea5 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -26,18 +26,24 @@ struct debugfs_blob_wrapper {
unsigned long size;
};

-struct debugfs_reg32 {
+struct debugfs_reg {
char *name;
+ int size;
+ int bigendian;
unsigned long offset;
};

-struct debugfs_regset32 {
+#define debugfs_reg32 debugfs_reg
+
+struct debugfs_regset {
const struct debugfs_reg32 *regs;
int nregs;
void __iomem *base;
struct device *dev; /* Optional device for Runtime PM */
};

+#define debugfs_regset32 debugfs_regset
+
struct debugfs_u32_array {
u32 *array;
u32 n_elements;
@@ -145,12 +151,15 @@ struct dentry *debugfs_create_blob(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_blob_wrapper *blob);

-void debugfs_create_regset32(const char *name, umode_t mode,
+void debugfs_create_regset(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_regset32 *regset);

-void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
+#define debugfs_create_regset32 debugfs_create_regset
+
+void debugfs_print_regs(struct seq_file *s, const struct debugfs_reg32 *regs,
int nregs, void __iomem *base, char *prefix);
+#define debugfs_print_regs32 debugfs_print_regs

void debugfs_create_u32_array(const char *name, umode_t mode,
struct dentry *parent,
--
2.34.1