misc: Update read() and write() methods to return bytes xfered

At present these functions return 0 on success. For some devices we want
to know how many bytes were transferred. It seems useful to adjust the API
to be more like the POSIX read() and write() functions.

Update these two methods, a test and all users.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@st.com>

8 files changed, 27 insertions, 15 deletions

diff --git a/arch/arm/mach-stm32mp/cpu.c b/arch/arm/mach-stm32mp/cpu.c
index 0e01f8e613..b8933587ad 100644
--- a/arch/arm/mach-stm32mp/cpu.c
+++ b/arch/arm/mach-stm32mp/cpu.c
@@ -306,7 +306,7 @@ static int setup_mac_address(void)
 
 	ret = misc_read(dev, BSEC_OTP_MAC * 4 + STM32_BSEC_OTP_OFFSET,
 			otp, sizeof(otp));
-	if (ret)
+	if (ret < 0)
 		return ret;
 
 	for (i = 0; i < 6; i++)
@@ -344,7 +344,7 @@ static int setup_serial_number(void)
 
 	ret = misc_read(dev, BSEC_OTP_SERIAL * 4 + STM32_BSEC_OTP_OFFSET,
 			otp, sizeof(otp));
-	if (ret)
+	if (ret < 0)
 		return ret;
 
 	sprintf(serial_string, "%08x%08x%08x", otp[0], otp[1], otp[2]);
diff --git a/drivers/clk/clk_vexpress_osc.c b/drivers/clk/clk_vexpress_osc.c
index 7fef4b2e31..c692a6d0b8 100644
--- a/drivers/clk/clk_vexpress_osc.c
+++ b/drivers/clk/clk_vexpress_osc.c
@@ -29,7 +29,7 @@ static ulong vexpress_osc_clk_get_rate(struct clk *clk)
 
 	data = CLK_FUNCTION | priv->osc;
 	err = misc_read(vexpress_cfg, 0, &data, sizeof(data));
-	if (err)
+	if (err < 0)
 		return err;
 
 	return data;
@@ -53,7 +53,7 @@ static ulong vexpress_osc_clk_set_rate(struct clk *clk, ulong rate)
 	buffer[0] = CLK_FUNCTION | priv->osc;
 	buffer[1] = rate;
 	err = misc_write(vexpress_cfg, 0, buffer, 2 * sizeof(u32));
-	if (err)
+	if (err < 0)
 		return err;
 
 	return rate;
diff --git a/drivers/misc/altera_sysid.c b/drivers/misc/altera_sysid.c
index 883b2a35e0..eff33f7343 100644
--- a/drivers/misc/altera_sysid.c
+++ b/drivers/misc/altera_sysid.c
@@ -35,7 +35,7 @@ void display_sysid(void)
 	if (ret)
 		return;
 	ret = misc_read(dev, 0, &sysid, sizeof(sysid));
-	if (ret)
+	if (ret < 0)
 		return;
 
 	stamp = sysid[1];
diff --git a/drivers/misc/misc_sandbox.c b/drivers/misc/misc_sandbox.c
index e4164f76fb..f7c5b2e25f 100644
--- a/drivers/misc/misc_sandbox.c
+++ b/drivers/misc/misc_sandbox.c
@@ -20,7 +20,7 @@ int misc_sandbox_read(struct udevice *dev, int offset, void *buf, int size)
 
 	memcpy(buf, priv->mem + offset, size);
 
-	return 0;
+	return size;
 }
 
 int misc_sandbox_write(struct udevice *dev, int offset, const void *buf,
@@ -30,7 +30,7 @@ int misc_sandbox_write(struct udevice *dev, int offset, const void *buf,
 
 	memcpy(priv->mem + offset, buf, size);
 
-	return 0;
+	return size;
 }
 
 int misc_sandbox_ioctl(struct udevice *dev, unsigned long request, void *buf)
diff --git a/drivers/misc/rockchip-efuse.c b/drivers/misc/rockchip-efuse.c
index 8a213c9e27..2520c6a38e 100644
--- a/drivers/misc/rockchip-efuse.c
+++ b/drivers/misc/rockchip-efuse.c
@@ -65,7 +65,7 @@ static int dump_efuses(cmd_tbl_t *cmdtp, int flag,
 	}
 
 	ret = misc_read(dev, 0, &fuses, sizeof(fuses));
-	if (ret) {
+	if (ret < 0) {
 		printf("%s: misc_read failed\n", __func__);
 		return 0;
 	}
diff --git a/drivers/misc/stm32mp_fuse.c b/drivers/misc/stm32mp_fuse.c
index 2d661351a1..33943a231b 100644
--- a/drivers/misc/stm32mp_fuse.c
+++ b/drivers/misc/stm32mp_fuse.c
@@ -29,6 +29,9 @@ int fuse_read(u32 bank, u32 word, u32 *val)
 			return ret;
 		ret = misc_read(dev, word * 4 + STM32_BSEC_SHADOW_OFFSET,
 				val, 4);
+		if (ret < 0)
+			return ret;
+		ret = 0;
 		break;
 
 	default:
@@ -54,6 +57,9 @@ int fuse_prog(u32 bank, u32 word, u32 val)
 			return ret;
 		ret = misc_write(dev, word * 4 + STM32_BSEC_OTP_OFFSET,
 				 &val, 4);
+		if (ret < 0)
+			return ret;
+		ret = 0;
 		break;
 
 	default:
@@ -78,6 +84,9 @@ int fuse_sense(u32 bank, u32 word, u32 *val)
 		if (ret)
 			return ret;
 		ret = misc_read(dev, word * 4 + STM32_BSEC_OTP_OFFSET, val, 4);
+		if (ret < 0)
+			return ret;
+		ret = 0;
 		break;
 
 	default:
@@ -103,6 +112,9 @@ int fuse_override(u32 bank, u32 word, u32 val)
 			return ret;
 		ret = misc_write(dev, word * 4 + STM32_BSEC_SHADOW_OFFSET,
 				 &val, 4);
+		if (ret < 0)
+			return ret;
+		ret = 0;
 		break;
 
 	default:
diff --git a/include/misc.h b/include/misc.h
index 50515852b2..12d1325ee2 100644
--- a/include/misc.h
+++ b/include/misc.h
@@ -13,7 +13,7 @@
  * @buf: pointer to data buffer
  * @size: data size in bytes to read the device
  *
- * Return: 0 if OK, -ve on error
+ * Return: number of bytes read if OK (may be 0 if EOF), -ve on error
  */
 int misc_read(struct udevice *dev, int offset, void *buf, int size);
 
@@ -24,7 +24,7 @@ int misc_read(struct udevice *dev, int offset, void *buf, int size);
  * @buf: pointer to data buffer
  * @size: data size in bytes to write the device
  *
- * Return: 0 if OK, -ve on error
+ * Return: number of bytes written if OK (may be < @size), -ve on error
  */
 int misc_write(struct udevice *dev, int offset, void *buf, int size);
 
@@ -90,7 +90,7 @@ struct misc_ops {
 	 * @buf: pointer to data buffer
 	 * @size: data size in bytes to read the device
 	 *
-	 * Return: 0 if OK, -ve on error
+	 * Return: number of bytes read if OK (may be 0 if EOF), -ve on error
 	 */
 	int (*read)(struct udevice *dev, int offset, void *buf, int size);
 
@@ -101,7 +101,7 @@ struct misc_ops {
 	 * @buf: pointer to data buffer
 	 * @size: data size in bytes to write the device
 	 *
-	 * Return: 0 if OK, -ve on error
+	 * Return: number of bytes written if OK (may be < @size), -ve on error
 	 */
 	int (*write)(struct udevice *dev, int offset, const void *buf,
 		     int size);
diff --git a/test/dm/misc.c b/test/dm/misc.c
index 61279665ef..4d4232adf1 100644
--- a/test/dm/misc.c
+++ b/test/dm/misc.c
@@ -21,9 +21,9 @@ static int dm_test_misc(struct unit_test_state *uts)
 	ut_assertok(uclass_get_device_by_name(UCLASS_MISC, "misc-test", &dev));
 
 	/* Read / write tests */
-	ut_assertok(misc_write(dev, 0, "TEST", 4));
-	ut_assertok(misc_write(dev, 4, "WRITE", 5));
-	ut_assertok(misc_read(dev, 0, buf, 9));
+	ut_asserteq(4, misc_write(dev, 0, "TEST", 4));
+	ut_asserteq(5, misc_write(dev, 4, "WRITE", 5));
+	ut_asserteq(9, misc_read(dev, 0, buf, 9));
 
 	ut_assertok(memcmp(buf, "TESTWRITE", 9));