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Message-Id: <20211217224104.1747758-2-linuxkernel@fbautosys.co.uk>
Date: Fri, 17 Dec 2021 22:41:00 +0000
From: linuxkernel@...utosys.co.uk
To: linux-kernel@...r.kernel.org
Cc: broonie@...nel.org
Subject: [RFC PATCH 1/5] regmap: Add Parity bit Calculation to regmaps
From: Christopher Tyerman <c.tyerman@...ebladeautomationsystems.co.uk>
regmap.h
Added parity_read_mask to regmap_config
Added parity_write_mask to regmap_config
Added (*parity_calc)() to regmap_config
Added regmap_parity_calc_even() Added regmap_parity_calc_odd()
internal.h
Added parity_read_mask to regmap
Added parity_write_mask to regmap
Added (*parity_calc) to regmap
regmap.c
Altered _regmap_raw_write_impl() to calculate parity
Altered _regmap_raw_read() to calculate parity
Added regmap_set_work_buf_parity_mask()
Added regmap_parity_calc_even()
Added regmap_parity_calc_odd()
Added parity_even()
Added parity16_even(u16 v)
Added parity32_even(u32 v)
Added parity64_even(u64 v)
Signed-off-by: Christopher Tyerman <c.tyerman@...ebladeautomationsystems.co.uk>
---
drivers/base/regmap/internal.h | 6 ++
drivers/base/regmap/regmap.c | 168 ++++++++++++++++++++++++++++++++-
include/linux/regmap.h | 32 +++++++
3 files changed, 204 insertions(+), 2 deletions(-)
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index b1905916f7af..78df50694cf4 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -168,6 +168,12 @@ struct regmap {
/* if set, the regmap core can sleep */
bool can_sleep;
+
+ unsigned long parity_write_mask;
+ unsigned long parity_read_mask;
+
+ bool (*parity_calc)(unsigned long rwmask, unsigned int reg,
+ const void *val, size_t val_len);
};
struct regcache_ops {
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 2d74f9f82aa9..05c104659381 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -57,6 +57,13 @@ static int _regmap_bus_reg_write(void *context, unsigned int reg,
static int _regmap_bus_raw_write(void *context, unsigned int reg,
unsigned int val);
+static bool parity_even(uint v);
+
+static bool parity8_even(u8 v);
+static bool parity16_even(u16 v);
+static bool parity32_even(u32 v);
+static bool parity64_even(u64 v);
+
bool regmap_reg_in_ranges(unsigned int reg,
const struct regmap_range *ranges,
unsigned int nranges)
@@ -892,6 +899,14 @@ struct regmap *__regmap_init(struct device *dev,
map->reg_update_bits = bus->reg_update_bits;
}
+ map->parity_write_mask = config->parity_write_mask;
+ map->parity_read_mask = config->parity_read_mask;
+
+ if (config->parity_calc)
+ map->parity_calc = config->parity_calc;
+ else
+ map->parity_calc = regmap_parity_calc_even;
+
reg_endian = regmap_get_reg_endian(bus, config);
val_endian = regmap_get_val_endian(dev, bus, config);
@@ -1655,6 +1670,31 @@ static void regmap_set_work_buf_flag_mask(struct regmap *map, int max_bytes,
buf[i] |= (mask >> (8 * i)) & 0xff;
}
+static void regmap_set_work_buf_parity_mask(struct regmap *map, int max_bytes,
+ unsigned long mask, unsigned long rwmask,
+ unsigned int reg, const void *val, size_t val_len)
+{
+
+ bool paritybit;
+ u8 *buf;
+ int i;
+
+ if (!mask || !map->work_buf)
+ return;
+
+ paritybit = map->parity_calc(rwmask, reg, val, val_len);
+
+
+ if (paritybit) {
+ buf = map->work_buf;
+
+ for (i = 0; i < max_bytes; i++)
+ buf[i] |= (mask >> (8 * i)) & 0xff;
+ }
+}
+
+
+
static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
const void *val, size_t val_len, bool noinc)
{
@@ -1736,7 +1776,12 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
map->format.format_reg(map->work_buf, reg, map->reg_shift);
regmap_set_work_buf_flag_mask(map, map->format.reg_bytes,
- map->write_flag_mask);
+ map->write_flag_mask);
+
+
+ regmap_set_work_buf_parity_mask(map, map->format.reg_bytes,
+ map->parity_write_mask, map->write_flag_mask, reg, val, val_len);
+
/*
* Essentially all I/O mechanisms will be faster with a single
@@ -1748,6 +1793,9 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
val = work_val;
}
+
+
+
if (map->async && map->bus->async_write) {
struct regmap_async *async;
@@ -2674,7 +2722,12 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
map->format.format_reg(map->work_buf, reg, map->reg_shift);
regmap_set_work_buf_flag_mask(map, map->format.reg_bytes,
- map->read_flag_mask);
+ map->read_flag_mask);
+
+ regmap_set_work_buf_parity_mask(map, map->format.reg_bytes,
+ map->parity_read_mask, map->read_flag_mask, reg,
+ val, val_len);
+
trace_regmap_hw_read_start(map, reg, val_len / map->format.val_bytes);
ret = map->bus->read(map->bus_context, map->work_buf,
@@ -3340,3 +3393,114 @@ static int __init regmap_initcall(void)
return 0;
}
postcore_initcall(regmap_initcall);
+
+
+/**
+ * regmap_parity_calc_even() - calculates Value of parity bit for even parity
+ *
+ * @rwmask: value of the read/write mask
+ * @reg: value of register
+ * @val: pointer to value of data
+ * @val_len: size of val
+ *
+ * Calculate the value of the parity bit for even parity
+ */
+bool regmap_parity_calc_even(unsigned long rwmask, unsigned int reg,
+ const void *val, size_t val_len)
+{
+ bool paritybuf = 0;
+ uint count = 0;
+
+ while (count < val_len) {
+ if (val_len - count >= 8) {
+ paritybuf ^= parity64_even(*(u64 *)val+count);
+ count += 8;
+ } else if (val_len - count >= 4) {
+ paritybuf ^= parity32_even(*(u32 *)val+count);
+ count += 4;
+ } else if (val_len - count >= 2) {
+ paritybuf ^= parity16_even(*(u16 *)val+count);
+ count += 2;
+ } else if (val_len - count >= 1) {
+ paritybuf ^= parity8_even(*(u8 *)val+count);
+ count += 1;
+ }
+ }
+
+ return (parity_even(rwmask) ^ parity_even(reg) ^ paritybuf);
+}
+EXPORT_SYMBOL_GPL(regmap_parity_calc_even);
+
+/**
+ * regmap_parity_calc_odd() - calculates Value of parity bit for odd parity
+ *
+ * @rwmask: value of the read/write mask
+ * @reg: value of register
+ * @val: pointer to value of data
+ * @val_len: size of val
+ *
+ * Calculate the value of the parity bit for odd parity
+ */
+
+bool regmap_parity_calc_odd(unsigned long rwmask, unsigned int reg,
+ const void *val, size_t val_len)
+{
+ return !(regmap_parity_calc_even(rwmask, reg, val, val_len));
+
+
+}
+EXPORT_SYMBOL_GPL(regmap_parity_calc_odd);
+
+static bool parity_even(uint v)
+{
+ switch (sizeof(v)) {
+ case 1:
+ return parity8_even((u8)v);
+ case 2:
+ return parity16_even((u16)v);
+ case 4:
+ return parity32_even((u32)v);
+ case 8:
+ default:
+ return parity64_even((u64)v);
+
+ }
+}
+static bool parity8_even(u8 v)
+{
+ v ^= v >> 4;
+ v ^= v >> 2;
+ v ^= v >> 1;
+ return v & 1;
+}
+
+
+static bool parity16_even(u16 v)
+{
+ v ^= v >> 8;
+ v ^= v >> 4;
+ v ^= v >> 2;
+ v ^= v >> 1;
+ return v & 1;
+}
+
+static bool parity32_even(u32 v)
+{
+ v ^= v >> 16;
+ v ^= v >> 8;
+ v ^= v >> 4;
+ v ^= v >> 2;
+ v ^= v >> 1;
+ return v & 1;
+}
+
+static bool parity64_even(u64 v)
+{
+ v ^= v >> 32;
+ v ^= v >> 16;
+ v ^= v >> 8;
+ v ^= v >> 4;
+ v ^= v >> 2;
+ v ^= v >> 1;
+ return v & 1;
+}
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 22652e5fbc38..511fc9228e1d 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -354,6 +354,10 @@ typedef void (*regmap_unlock)(void *);
* @hwlock_mode: The hardware spinlock mode, should be HWLOCK_IRQSTATE,
* HWLOCK_IRQ or 0.
* @can_sleep: Optional, specifies whether regmap operations can sleep.
+ *
+ * @parity_read_mask: bit mask of location of parity bit for reads
+ * @parity_write_mask: bit mask of location of parity bit for writes
+ * @parity_calc: Optional callback to calculate parity, defaults to even parity
*/
struct regmap_config {
const char *name;
@@ -416,6 +420,12 @@ struct regmap_config {
unsigned int hwlock_mode;
bool can_sleep;
+
+ unsigned long parity_read_mask;
+ unsigned long parity_write_mask;
+ bool (*parity_calc)(unsigned long rwmask, unsigned int reg,
+ const void *val, size_t val_len);
+
};
/**
@@ -1237,6 +1247,11 @@ static inline int regmap_clear_bits(struct regmap *map,
int regmap_test_bits(struct regmap *map, unsigned int reg, unsigned int bits);
+bool regmap_parity_calc_even(unsigned long rwmask, unsigned int reg,
+ const void *val, size_t val_len);
+bool regmap_parity_calc_odd(unsigned long rwmask, unsigned int reg,
+ const void *val, size_t val_len);
+
/**
* struct reg_field - Description of an register field
*
@@ -1866,6 +1881,23 @@ static inline struct device *regmap_get_device(struct regmap *map)
return NULL;
}
+static inline bool regmap_parity_calc_even(unsigned long rwmask, unsigned int reg,
+ const void *val, size_t val_len)
+{
+ WARN_ONCE(1, "regmap API is disabled");
+ return NULL;
+}
+
+static inline bool regmap_parity_calc_odd(unsigned long rwmask, unsigned int reg,
+ const void *val, size_t val_len)
+{
+ WARN_ONCE(1, "regmap API is disabled");
+ return NULL;
+}
+
+
#endif
+
+
#endif
--
2.25.1
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