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Date: Wed, 13 Sep 2023 12:20:21 +0100
From: Ian Abbott <abbotti@....co.uk>
To: linux-kernel@...r.kernel.org
Cc: Arnd Bergmann <arnd@...nel.org>,
Niklas Schnelle <schnelle@...ux.ibm.com>,
Ian Abbott <abbotti@....co.uk>
Subject: [PATCH 02/13] comedi: comedi_8254: Use a call-back function for register access
Rework the comedi_8254 module to use a call-back function for register
access. This will make it easier to isolate the parts that will depend
on the `CONFIG_HAS_IOPORT` macro being defined and also allows the
possibility of supplying an external callback function during
initialization by a variant of the `comedi_8254_init()` and
`comedi_8254_mm_init()` functions, although that has not been
implemented yet.
The `struct comedi_8254` members have been changed to use a pointer to a
callback function and a context of type `unsigned long`. The
`comedi_8254_init()` and `comedi_8254_mm_init()` functions use an
internal callback function and set the context to the base address of
the registers (for `comedi_8254_mm_init()` that involves converting a
`void __iomem *` to `unsigned long`).
A minor change to `dio200_subdev_8254_offset()` in the
amplc_dio200_common module has been made due to the changes in `struct
comedi_8254`.
Cc: Arnd Bergmann <arnd@...nel.org>
Cc: Niklas Schnelle <schnelle@...ux.ibm.com>
Signed-off-by: Ian Abbott <abbotti@....co.uk>
---
drivers/comedi/drivers/amplc_dio200_common.c | 4 +-
drivers/comedi/drivers/comedi_8254.c | 177 +++++++++++++------
include/linux/comedi/comedi_8254.h | 22 ++-
3 files changed, 144 insertions(+), 59 deletions(-)
diff --git a/drivers/comedi/drivers/amplc_dio200_common.c b/drivers/comedi/drivers/amplc_dio200_common.c
index ff651f2eb86c..2c1507a23f8a 100644
--- a/drivers/comedi/drivers/amplc_dio200_common.c
+++ b/drivers/comedi/drivers/amplc_dio200_common.c
@@ -149,9 +149,9 @@ static unsigned int dio200_subdev_8254_offset(struct comedi_device *dev,
/* get the offset that was passed to comedi_8254_*_init() */
if (dev->mmio)
- offset = i8254->mmio - dev->mmio;
+ offset = (void __iomem *)i8254->context - dev->mmio;
else
- offset = i8254->iobase - dev->iobase;
+ offset = i8254->context - dev->iobase;
/* remove the shift that was added for PCIe boards */
if (board->is_pcie)
diff --git a/drivers/comedi/drivers/comedi_8254.c b/drivers/comedi/drivers/comedi_8254.c
index b4185c1b2695..3f8657fc7ee5 100644
--- a/drivers/comedi/drivers/comedi_8254.c
+++ b/drivers/comedi/drivers/comedi_8254.c
@@ -119,63 +119,101 @@
#include <linux/comedi/comedidev.h>
#include <linux/comedi/comedi_8254.h>
-static unsigned int __i8254_read(struct comedi_8254 *i8254, unsigned int reg)
+static unsigned int i8254_io8_cb(struct comedi_8254 *i8254, int dir,
+ unsigned int reg, unsigned int val)
{
- unsigned int reg_offset = (reg * i8254->iosize) << i8254->regshift;
- unsigned int val;
+ unsigned long iobase = i8254->context;
+ unsigned int reg_offset = (reg * I8254_IO8) << i8254->regshift;
- switch (i8254->iosize) {
- default:
- case I8254_IO8:
- if (i8254->mmio)
- val = readb(i8254->mmio + reg_offset);
- else
- val = inb(i8254->iobase + reg_offset);
- break;
- case I8254_IO16:
- if (i8254->mmio)
- val = readw(i8254->mmio + reg_offset);
- else
- val = inw(i8254->iobase + reg_offset);
- break;
- case I8254_IO32:
- if (i8254->mmio)
- val = readl(i8254->mmio + reg_offset);
- else
- val = inl(i8254->iobase + reg_offset);
- break;
+ if (dir) {
+ outb(val, iobase + reg_offset);
+ return 0;
+ } else {
+ return inb(iobase + reg_offset);
}
- return val & 0xff;
}
-static void __i8254_write(struct comedi_8254 *i8254,
- unsigned int val, unsigned int reg)
+static unsigned int i8254_io16_cb(struct comedi_8254 *i8254, int dir,
+ unsigned int reg, unsigned int val)
{
- unsigned int reg_offset = (reg * i8254->iosize) << i8254->regshift;
+ unsigned long iobase = i8254->context;
+ unsigned int reg_offset = (reg * I8254_IO16) << i8254->regshift;
- switch (i8254->iosize) {
- default:
- case I8254_IO8:
- if (i8254->mmio)
- writeb(val, i8254->mmio + reg_offset);
- else
- outb(val, i8254->iobase + reg_offset);
- break;
- case I8254_IO16:
- if (i8254->mmio)
- writew(val, i8254->mmio + reg_offset);
- else
- outw(val, i8254->iobase + reg_offset);
- break;
- case I8254_IO32:
- if (i8254->mmio)
- writel(val, i8254->mmio + reg_offset);
- else
- outl(val, i8254->iobase + reg_offset);
- break;
+ if (dir) {
+ outw(val, iobase + reg_offset);
+ return 0;
+ } else {
+ return inw(iobase + reg_offset);
+ }
+}
+
+static unsigned int i8254_io32_cb(struct comedi_8254 *i8254, int dir,
+ unsigned int reg, unsigned int val)
+{
+ unsigned long iobase = i8254->context;
+ unsigned int reg_offset = (reg * I8254_IO32) << i8254->regshift;
+
+ if (dir) {
+ outl(val, iobase + reg_offset);
+ return 0;
+ } else {
+ return inl(iobase + reg_offset);
+ }
+}
+
+static unsigned int i8254_mmio8_cb(struct comedi_8254 *i8254, int dir,
+ unsigned int reg, unsigned int val)
+{
+ void __iomem *mmiobase = (void __iomem *)i8254->context;
+ unsigned int reg_offset = (reg * I8254_IO8) << i8254->regshift;
+
+ if (dir) {
+ writeb(val, mmiobase + reg_offset);
+ return 0;
+ } else {
+ return readb(mmiobase + reg_offset);
+ }
+}
+
+static unsigned int i8254_mmio16_cb(struct comedi_8254 *i8254, int dir,
+ unsigned int reg, unsigned int val)
+{
+ void __iomem *mmiobase = (void __iomem *)i8254->context;
+ unsigned int reg_offset = (reg * I8254_IO16) << i8254->regshift;
+
+ if (dir) {
+ writew(val, mmiobase + reg_offset);
+ return 0;
+ } else {
+ return readw(mmiobase + reg_offset);
}
}
+static unsigned int i8254_mmio32_cb(struct comedi_8254 *i8254, int dir,
+ unsigned int reg, unsigned int val)
+{
+ void __iomem *mmiobase = (void __iomem *)i8254->context;
+ unsigned int reg_offset = (reg * I8254_IO32) << i8254->regshift;
+
+ if (dir) {
+ writel(val, mmiobase + reg_offset);
+ return 0;
+ } else {
+ return readl(mmiobase + reg_offset);
+ }
+}
+
+static unsigned int __i8254_read(struct comedi_8254 *i8254, unsigned int reg)
+{
+ return 0xff & i8254->iocb(i8254, 0, reg, 0);
+}
+
+static void __i8254_write(struct comedi_8254 *i8254,
+ unsigned int val, unsigned int reg)
+{
+ i8254->iocb(i8254, 1, reg, val);
+}
+
/**
* comedi_8254_status - return the status of a counter
* @i8254: comedi_8254 struct for the timer
@@ -571,8 +609,8 @@ void comedi_8254_subdevice_init(struct comedi_subdevice *s,
}
EXPORT_SYMBOL_GPL(comedi_8254_subdevice_init);
-static struct comedi_8254 *__i8254_init(unsigned long iobase,
- void __iomem *mmio,
+static struct comedi_8254 *__i8254_init(comedi_8254_iocb_fn *iocb,
+ unsigned long context,
unsigned int osc_base,
unsigned int iosize,
unsigned int regshift)
@@ -585,12 +623,15 @@ static struct comedi_8254 *__i8254_init(unsigned long iobase,
iosize == I8254_IO32))
return NULL;
+ if (!iocb)
+ return NULL;
+
i8254 = kzalloc(sizeof(*i8254), GFP_KERNEL);
if (!i8254)
return NULL;
- i8254->iobase = iobase;
- i8254->mmio = mmio;
+ i8254->iocb = iocb;
+ i8254->context = context;
i8254->iosize = iosize;
i8254->regshift = regshift;
@@ -617,7 +658,22 @@ struct comedi_8254 *comedi_8254_init(unsigned long iobase,
unsigned int iosize,
unsigned int regshift)
{
- return __i8254_init(iobase, NULL, osc_base, iosize, regshift);
+ comedi_8254_iocb_fn *iocb;
+
+ switch (iosize) {
+ case I8254_IO8:
+ iocb = i8254_io8_cb;
+ break;
+ case I8254_IO16:
+ iocb = i8254_io16_cb;
+ break;
+ case I8254_IO32:
+ iocb = i8254_io32_cb;
+ break;
+ default:
+ return NULL;
+ }
+ return __i8254_init(iocb, iobase, osc_base, iosize, regshift);
}
EXPORT_SYMBOL_GPL(comedi_8254_init);
@@ -634,7 +690,22 @@ struct comedi_8254 *comedi_8254_mm_init(void __iomem *mmio,
unsigned int iosize,
unsigned int regshift)
{
- return __i8254_init(0, mmio, osc_base, iosize, regshift);
+ comedi_8254_iocb_fn *iocb;
+
+ switch (iosize) {
+ case I8254_IO8:
+ iocb = i8254_mmio8_cb;
+ break;
+ case I8254_IO16:
+ iocb = i8254_mmio16_cb;
+ break;
+ case I8254_IO32:
+ iocb = i8254_mmio32_cb;
+ break;
+ default:
+ return NULL;
+ }
+ return __i8254_init(iocb, (unsigned long)mmio, osc_base, iosize, regshift);
}
EXPORT_SYMBOL_GPL(comedi_8254_mm_init);
diff --git a/include/linux/comedi/comedi_8254.h b/include/linux/comedi/comedi_8254.h
index d8264417e53c..18d12321c87d 100644
--- a/include/linux/comedi/comedi_8254.h
+++ b/include/linux/comedi/comedi_8254.h
@@ -57,10 +57,24 @@ struct comedi_subdevice;
/* counter maps zero to 0x10000 */
#define I8254_MAX_COUNT 0x10000
+struct comedi_8254;
+
+/**
+ * typedef comedi_8254_iocb_fn - call-back function type for 8254 register access
+ * @i8254: pointer to struct comedi_8254
+ * @dir: direction (0 = read, 1 = write)
+ * @reg: register number
+ * @val: value to write
+ *
+ * Return: Register value when reading, 0 when writing.
+ */
+typedef unsigned int comedi_8254_iocb_fn(struct comedi_8254 *i8254, int dir,
+ unsigned int reg, unsigned int val);
+
/**
* struct comedi_8254 - private data used by this module
- * @iobase: PIO base address of the registers (in/out)
- * @mmio: MMIO base address of the registers (read/write)
+ * @iocb: I/O call-back function for register access
+ * @context: context for register access (e.g. a base address)
* @iosize: I/O size used to access the registers (b/w/l)
* @regshift: register gap shift
* @osc_base: cascaded oscillator speed in ns
@@ -76,8 +90,8 @@ struct comedi_subdevice;
* @insn_config: driver specific (*insn_config) callback
*/
struct comedi_8254 {
- unsigned long iobase;
- void __iomem *mmio;
+ comedi_8254_iocb_fn *iocb;
+ unsigned long context;
unsigned int iosize;
unsigned int regshift;
unsigned int osc_base;
--
2.40.1
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