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From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mark Brown <broonie@kernel.org>,
        Aidan MacDonald <aidanmacdonald.0x0@gmail.com>,
        linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>
Subject: [PATCH v1 5/5] regmap: mmio: Introduce IO accessors that can talk to IO port
Date:   Fri,  5 Aug 2022 23:53:21 +0300
Message-Id: <20220805205321.19452-5-andriy.shevchenko@linux.intel.com>
In-Reply-To: <20220805205321.19452-1-andriy.shevchenko@linux.intel.com>
References: <20220805205321.19452-1-andriy.shevchenko@linux.intel.com>
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Currently regmap MMIO is inconsistent with IO accessors. I.e.
the Big Endian counterparts are using ioreadXXbe() / iowriteXXbe()
which are not clean implementations of readXXbe(). Besides that
some users may use regmap MMIO for IO ports, and this can be done
by assigning ioreadXX()/iowriteXX() and their Big Endian counterparts
to the regmap context.

That said, reimplement current Big Endian MMIO accessors by replacing
ioread()/iowrite() with respective read()/write() and swab() calls.
While at it, add IO port support with a corresponding flag added.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/base/regmap/regmap-mmio.c | 102 +++++++++++++++++++++++++++---
 include/linux/regmap.h            |   3 +
 2 files changed, 96 insertions(+), 9 deletions(-)

diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c
index 698295a8f5a6..6a0d370ac83b 100644
--- a/drivers/base/regmap/regmap-mmio.c
+++ b/drivers/base/regmap/regmap-mmio.c
@@ -74,6 +74,12 @@ static void regmap_mmio_write8_relaxed(struct regmap_mmio_context *ctx,
 	writeb_relaxed(val, ctx->regs + reg);
 }
 
+static void regmap_mmio_iowrite8(struct regmap_mmio_context *ctx,
+				 unsigned int reg, unsigned int val)
+{
+	iowrite8(val, ctx->regs + reg);
+}
+
 static void regmap_mmio_write16le(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
 				  unsigned int val)
@@ -88,9 +94,21 @@ static void regmap_mmio_write16le_relaxed(struct regmap_mmio_context *ctx,
 	writew_relaxed(val, ctx->regs + reg);
 }
 
+static void regmap_mmio_iowrite16le(struct regmap_mmio_context *ctx,
+				    unsigned int reg, unsigned int val)
+{
+	iowrite16(val, ctx->regs + reg);
+}
+
 static void regmap_mmio_write16be(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
 				  unsigned int val)
+{
+	writew(swab16(val), ctx->regs + reg);
+}
+
+static void regmap_mmio_iowrite16be(struct regmap_mmio_context *ctx,
+				    unsigned int reg, unsigned int val)
 {
 	iowrite16be(val, ctx->regs + reg);
 }
@@ -109,9 +127,21 @@ static void regmap_mmio_write32le_relaxed(struct regmap_mmio_context *ctx,
 	writel_relaxed(val, ctx->regs + reg);
 }
 
+static void regmap_mmio_iowrite32le(struct regmap_mmio_context *ctx,
+				    unsigned int reg, unsigned int val)
+{
+	iowrite32(val, ctx->regs + reg);
+}
+
 static void regmap_mmio_write32be(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
 				  unsigned int val)
+{
+	writel(swab32(val), ctx->regs + reg);
+}
+
+static void regmap_mmio_iowrite32be(struct regmap_mmio_context *ctx,
+				    unsigned int reg, unsigned int val)
 {
 	iowrite32be(val, ctx->regs + reg);
 }
@@ -144,6 +174,12 @@ static unsigned int regmap_mmio_read8_relaxed(struct regmap_mmio_context *ctx,
 	return readb_relaxed(ctx->regs + reg);
 }
 
+static unsigned int regmap_mmio_ioread8(struct regmap_mmio_context *ctx,
+					unsigned int reg)
+{
+	return ioread8(ctx->regs + reg);
+}
+
 static unsigned int regmap_mmio_read16le(struct regmap_mmio_context *ctx,
 				         unsigned int reg)
 {
@@ -156,8 +192,20 @@ static unsigned int regmap_mmio_read16le_relaxed(struct regmap_mmio_context *ctx
 	return readw_relaxed(ctx->regs + reg);
 }
 
+static unsigned int regmap_mmio_ioread16le(struct regmap_mmio_context *ctx,
+					   unsigned int reg)
+{
+	return ioread16(ctx->regs + reg);
+}
+
 static unsigned int regmap_mmio_read16be(struct regmap_mmio_context *ctx,
 				         unsigned int reg)
+{
+	return swab16(readw(ctx->regs + reg));
+}
+
+static unsigned int regmap_mmio_ioread16be(struct regmap_mmio_context *ctx,
+					   unsigned int reg)
 {
 	return ioread16be(ctx->regs + reg);
 }
@@ -174,8 +222,20 @@ static unsigned int regmap_mmio_read32le_relaxed(struct regmap_mmio_context *ctx
 	return readl_relaxed(ctx->regs + reg);
 }
 
+static unsigned int regmap_mmio_ioread32le(struct regmap_mmio_context *ctx,
+					   unsigned int reg)
+{
+	return ioread32(ctx->regs + reg);
+}
+
 static unsigned int regmap_mmio_read32be(struct regmap_mmio_context *ctx,
 				         unsigned int reg)
+{
+	return swab32(readl(ctx->regs + reg));
+}
+
+static unsigned int regmap_mmio_ioread32be(struct regmap_mmio_context *ctx,
+					   unsigned int reg)
 {
 	return ioread32be(ctx->regs + reg);
 }
@@ -253,7 +313,10 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 #endif
 		switch (config->val_bits) {
 		case 8:
-			if (config->use_relaxed_mmio) {
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread8;
+				ctx->reg_write = regmap_mmio_iowrite8;
+			} else if (config->use_relaxed_mmio) {
 				ctx->reg_read = regmap_mmio_read8_relaxed;
 				ctx->reg_write = regmap_mmio_write8_relaxed;
 			} else {
@@ -262,7 +325,10 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 			}
 			break;
 		case 16:
-			if (config->use_relaxed_mmio) {
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread16le;
+				ctx->reg_write = regmap_mmio_iowrite16le;
+			} else if (config->use_relaxed_mmio) {
 				ctx->reg_read = regmap_mmio_read16le_relaxed;
 				ctx->reg_write = regmap_mmio_write16le_relaxed;
 			} else {
@@ -271,7 +337,10 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 			}
 			break;
 		case 32:
-			if (config->use_relaxed_mmio) {
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread32le;
+				ctx->reg_write = regmap_mmio_iowrite32le;
+			} else if (config->use_relaxed_mmio) {
 				ctx->reg_read = regmap_mmio_read32le_relaxed;
 				ctx->reg_write = regmap_mmio_write32le_relaxed;
 			} else {
@@ -290,16 +359,31 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 #endif
 		switch (config->val_bits) {
 		case 8:
-			ctx->reg_read = regmap_mmio_read8;
-			ctx->reg_write = regmap_mmio_write8;
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread8;
+				ctx->reg_write = regmap_mmio_iowrite8;
+			} else {
+				ctx->reg_read = regmap_mmio_read8;
+				ctx->reg_write = regmap_mmio_write8;
+			}
 			break;
 		case 16:
-			ctx->reg_read = regmap_mmio_read16be;
-			ctx->reg_write = regmap_mmio_write16be;
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread16be;
+				ctx->reg_write = regmap_mmio_iowrite16be;
+			} else {
+				ctx->reg_read = regmap_mmio_read16be;
+				ctx->reg_write = regmap_mmio_write16be;
+			}
 			break;
 		case 32:
-			ctx->reg_read = regmap_mmio_read32be;
-			ctx->reg_write = regmap_mmio_write32be;
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread32be;
+				ctx->reg_write = regmap_mmio_iowrite32be;
+			} else {
+				ctx->reg_read = regmap_mmio_read32be;
+				ctx->reg_write = regmap_mmio_write32be;
+			}
 			break;
 		default:
 			ret = -EINVAL;
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 7cf2157134ac..8cccc247cd37 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -311,6 +311,8 @@ typedef void (*regmap_unlock)(void *);
  *		  This field is a duplicate of a similar file in
  *		  'struct regmap_bus' and serves exact same purpose.
  *		   Use it only for "no-bus" cases.
+ * @io_port:	  Support IO port accessors. Makes sense only when MMIO vs. IO port
+ *		  access can be distinguished.
  * @max_register: Optional, specifies the maximum valid register address.
  * @wr_table:     Optional, points to a struct regmap_access_table specifying
  *                valid ranges for write access.
@@ -399,6 +401,7 @@ struct regmap_config {
 	size_t max_raw_write;
 
 	bool fast_io;
+	bool io_port;
 
 	unsigned int max_register;
 	const struct regmap_access_table *wr_table;
-- 
2.35.1