[U-Boot] [PATCH 0/3] rockchip: Use the standard debug UART on rockchip

[U-Boot] [PATCH 0/3] rockchip: Use the standard debug UART on rockchip

[Simon Glass]

The RK3036 has only 8KB of RAM available for SPL. At present it uses its own
debug UART code.

By allowing the ns16550 driver to provide a debug UART without providing a
full serial driver, we can enable a UART with a very small overhead. This
requires addition Kconfig options. The debug UART supports printhex8(),
printascii() and a few other functions.

The root driver and uclass are pulled in by this series, but their size is
very small. It would possible to drop these by disabling CONFIG_DM_SERIAL.
However the ns16550 driver makes this hard, due to it supporting operation
without driver model, and operating differently in this case.


Simon Glass (3):
  dm: serial: Allow the UART driver to be dropped from the image
  dm: ns16550: Allow the driver to be omitted if requested
  rockchip: Use the debug UART on rk3036

 arch/arm/mach-rockchip/Makefile           |  1 -
 arch/arm/mach-rockchip/rk3036-board-spl.c |  9 ++++-
 arch/arm/mach-rockchip/rk_early_print.c   | 63 -------------------------------
 configs/evb-rk3036_defconfig              |  6 +++
 drivers/serial/Kconfig                    | 20 ++++++++++
 drivers/serial/ns16550.c                  |  2 +
 drivers/serial/serial-uclass.c            |  2 +
 include/configs/rk3036_common.h           |  2 +
 8 files changed, 40 insertions(+), 65 deletions(-)
 delete mode 100644 arch/arm/mach-rockchip/rk_early_print.c

-- 
2.6.0.rc2.230.g3dd15c0

[U-Boot] [PATCH 1/3] dm: serial: Allow the UART driver to be dropped from the image

[Simon Glass]

In very very space-constrained devices even the full UART driver is too
large. In this case the debug UART can still be used in some cases.

Add options to enable the UART driver in SPL and U-Boot proper. Enable both
options by default.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

 drivers/serial/Kconfig         | 20 ++++++++++++++++++++
 drivers/serial/serial-uclass.c |  2 ++
 2 files changed, 22 insertions(+)

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 1fc287e..04541c9 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -15,6 +15,26 @@ config REQUIRE_SERIAL_CONSOLE
 	  during serial port initialization (default y). Set this to n on
 	  boards which have no debug serial port whatsoever.
 
+config SERIAL_PRESENT
+	bool "Provide a serial driver"
+	depends on DM_SERIAL
+	default y
+	help
+	  In very space-constrained devices even the full UART driver is too
+	  large. In this case the debug UART can still be used in some cases.
+	  This option enables the full UART in U-Boot, so if is it disabled,
+	  the full UART driver will be omitted, thus saving space.
+
+config SPL_SERIAL_PRESENT
+	bool "Provide a serial driver in SPL"
+	depends on DM_SERIAL
+	default y
+	help
+	  In very space-constrained devices even the full UART driver is too
+	  large. In this case the debug UART can still be used in some cases.
+	  This option enables the full UART in SPL, so if is it disabled,
+	  the full UART driver will be omitted, thus saving space.
+
 config DM_SERIAL
 	bool "Enable Driver Model for serial drivers"
 	depends on DM
diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
index 4bf9a5c..95c3b91 100644
--- a/drivers/serial/serial-uclass.c
+++ b/drivers/serial/serial-uclass.c
@@ -287,6 +287,7 @@ static int on_baudrate(const char *name, const char *value, enum env_op op,
 }
 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
 
+#if CONFIG_IS_ENABLED(SERIAL_PRESENT)
 static int serial_post_probe(struct udevice *dev)
 {
 	struct dm_serial_ops *ops = serial_get_ops(dev);
@@ -356,3 +357,4 @@ UCLASS_DRIVER(serial) = {
 	.pre_remove	= serial_pre_remove,
 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
 };
+#endif
-- 
2.6.0.rc2.230.g3dd15c0

[U-Boot] [PATCH 2/3] dm: ns16550: Allow the driver to be omitted if requested

[Simon Glass]

Allow the ns16550 debug UART to be used without the full driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

 drivers/serial/ns16550.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 3fab3f1..2025423 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -440,6 +440,7 @@ static const struct udevice_id ns16550_serial_ids[] = {
 };
 #endif
 
+#if CONFIG_IS_ENABLED(SERIAL_PRESENT)
 U_BOOT_DRIVER(ns16550_serial) = {
 	.name	= "ns16550_serial",
 	.id	= UCLASS_SERIAL,
@@ -453,4 +454,5 @@ U_BOOT_DRIVER(ns16550_serial) = {
 	.ops	= &ns16550_serial_ops,
 	.flags	= DM_FLAG_PRE_RELOC,
 };
+#endif
 #endif /* CONFIG_DM_SERIAL */
-- 
2.6.0.rc2.230.g3dd15c0

[U-Boot] [PATCH 3/3] rockchip: Use the debug UART on rk3036

[Simon Glass]

Rather than using a new debug UART implementation, use the standard one
provided by U-Boot.
Signed-off-by: Simon Glass <sjg@chromium.org>
---

 arch/arm/mach-rockchip/Makefile           |  1 -
 arch/arm/mach-rockchip/rk3036-board-spl.c |  9 ++++-
 arch/arm/mach-rockchip/rk_early_print.c   | 63 -------------------------------
 configs/evb-rk3036_defconfig              |  6 +++
 include/configs/rk3036_common.h           |  2 +
 5 files changed, 16 insertions(+), 65 deletions(-)
 delete mode 100644 arch/arm/mach-rockchip/rk_early_print.c

diff --git a/arch/arm/mach-rockchip/Makefile b/arch/arm/mach-rockchip/Makefile
index b703c3c..1cc4a96 100644
--- a/arch/arm/mach-rockchip/Makefile
+++ b/arch/arm/mach-rockchip/Makefile
@@ -11,7 +11,6 @@ else
 obj-$(CONFIG_ROCKCHIP_RK3288) += board.o
 endif
 obj-y += rk_timer.o
-obj-y += rk_early_print.o
 obj-$(CONFIG_$(SPL_)ROCKCHIP_COMMON) += common.o
 obj-$(CONFIG_ROCKCHIP_RK3288) += rk3288/
 obj-$(CONFIG_ROCKCHIP_RK3036) += rk3036/
diff --git a/arch/arm/mach-rockchip/rk3036-board-spl.c b/arch/arm/mach-rockchip/rk3036-board-spl.c
index 3a1491c..8015481 100644
--- a/arch/arm/mach-rockchip/rk3036-board-spl.c
+++ b/arch/arm/mach-rockchip/rk3036-board-spl.c
@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <debug_uart.h>
 #include <asm/io.h>
 #include <asm/arch/grf_rk3036.h>
 #include <asm/arch/hardware.h>
@@ -34,7 +35,7 @@ void board_init_f(ulong dummy)
 		     GPIO1C2_MASK << GPIO1C2_SHIFT,
 		     GPIO1C3_UART2_SOUT << GPIO1C3_SHIFT |
 		     GPIO1C2_UART2_SIN << GPIO1C2_SHIFT);
-	rk_uart_init((void *)DEBUG_UART_BASE);
+	debug_uart_init();
 #endif
 	rockchip_timer_init();
 	sdram_init();
@@ -53,3 +54,9 @@ void board_init_r(gd_t *id, ulong dest_addr)
 	while (1)
 		;
 }
+
+void hang(void)
+{
+	while (1)
+		;
+}
diff --git a/arch/arm/mach-rockchip/rk_early_print.c b/arch/arm/mach-rockchip/rk_early_print.c
deleted file mode 100644
index a1c14b0..0000000
--- a/arch/arm/mach-rockchip/rk_early_print.c
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * (C) Copyright 2015 Rockchip Electronics Co., Ltd
- *
- * SPDX-License-Identifier:     GPL-2.0+
- */
-
-#include <asm/io.h>
-#include <asm/arch/uart.h>
-#include <common.h>
-
-static struct rk_uart *uart_ptr;
-
-static void uart_wrtie_byte(char byte)
-{
-	writel(byte, &uart_ptr->rbr);
-	while (!(readl(&uart_ptr->lsr) & 0x40))
-		;
-}
-
-void print(char *s)
-{
-	while (*s) {
-		if (*s == '\n')
-			uart_wrtie_byte('\r');
-	    uart_wrtie_byte(*s);
-	    s++;
-	}
-}
-
-void print_hex(unsigned int n)
-{
-	int i;
-	int temp;
-
-	uart_wrtie_byte('0');
-	uart_wrtie_byte('x');
-
-	for (i = 8; i > 0; i--) {
-		temp = (n >> (i - 1) * 4) & 0x0f;
-		if (temp < 10)
-			uart_wrtie_byte((char)(temp + '0'));
-		else
-			uart_wrtie_byte((char)(temp - 10 + 'a'));
-	}
-	uart_wrtie_byte('\n');
-	uart_wrtie_byte('\r');
-}
-
-/*
- * TODO: since rk3036 only 4K sram to use in SPL, for saving space,
- * we implement uart driver this way, we should convert this to use
- * ns16550 driver in future, which support DEBUG_UART in the standard way
- */
-void rk_uart_init(void *base)
-{
-	uart_ptr = (struct rk_uart *)base;
-	writel(0x83, &uart_ptr->lcr);
-	writel(0x0d, &uart_ptr->rbr);
-	writel(0x03, &uart_ptr->lcr);
-
-	/* fifo enable, sfe is shadow register of FCR[0] */
-	writel(0x01, &uart_ptr->sfe);
-}
diff --git a/configs/evb-rk3036_defconfig b/configs/evb-rk3036_defconfig
index 2e915ff..c196bd6 100644
--- a/configs/evb-rk3036_defconfig
+++ b/configs/evb-rk3036_defconfig
@@ -24,3 +24,9 @@ CONFIG_DM_MMC=y
 CONFIG_USE_PRIVATE_LIBGCC=y
 CONFIG_CMD_DHRYSTONE=y
 CONFIG_ERRNO_STR=y
+CONFIG_DEBUG_UART=y
+CONFIG_DEBUG_UART_NS16550=y
+CONFIG_DEBUG_UART_BASE=0x20068000
+CONFIG_DEBUG_UART_CLOCK=24000000
+CONFIG_DEBUG_UART_SHIFT=2
+# CONFIG_SPL_SERIAL_PRESENT is not set
diff --git a/include/configs/rk3036_common.h b/include/configs/rk3036_common.h
index f753e68..d22ea74 100644
--- a/include/configs/rk3036_common.h
+++ b/include/configs/rk3036_common.h
@@ -24,6 +24,8 @@
 #define CONFIG_SYS_TIMER_BASE		0x200440a0 /* TIMER5 */
 #define CONFIG_SYS_TIMER_COUNTER	(CONFIG_SYS_TIMER_BASE + 8)
 
+#define CONFIG_SPL_SERIAL_SUPPORT
+
 #define CONFIG_SYS_NS16550
 #define CONFIG_SYS_NS16550_MEM32
 
-- 
2.6.0.rc2.230.g3dd15c0

[U-Boot] [PATCH 0/3] rockchip: Use the standard debug UART on rockchip

[hl]

Hi Simon.

     Thank you for updating this series patch, i have verified it in 
evb-rk3036 board,
it worked.


On 14/12/15 12:36, Simon Glass wrote:
> The RK3036 has only 8KB of RAM available for SPL. At present it uses its own
> debug UART code.
>
> By allowing the ns16550 driver to provide a debug UART without providing a
> full serial driver, we can enable a UART with a very small overhead. This
> requires addition Kconfig options. The debug UART supports printhex8(),
> printascii() and a few other functions.
>
> The root driver and uclass are pulled in by this series, but their size is
> very small. It would possible to drop these by disabling CONFIG_DM_SERIAL.
> However the ns16550 driver makes this hard, due to it supporting operation
> without driver model, and operating differently in this case.
>
>
> Simon Glass (3):
>    dm: serial: Allow the UART driver to be dropped from the image
>    dm: ns16550: Allow the driver to be omitted if requested
>    rockchip: Use the debug UART on rk3036
>
>   arch/arm/mach-rockchip/Makefile           |  1 -
>   arch/arm/mach-rockchip/rk3036-board-spl.c |  9 ++++-
>   arch/arm/mach-rockchip/rk_early_print.c   | 63 -------------------------------
>   configs/evb-rk3036_defconfig              |  6 +++
>   drivers/serial/Kconfig                    | 20 ++++++++++
>   drivers/serial/ns16550.c                  |  2 +
>   drivers/serial/serial-uclass.c            |  2 +
>   include/configs/rk3036_common.h           |  2 +
>   8 files changed, 40 insertions(+), 65 deletions(-)
>   delete mode 100644 arch/arm/mach-rockchip/rk_early_print.c
>

-- 
Lin Huang

[U-Boot] [PATCH 1/3] dm: serial: Allow the UART driver to be dropped from the image

[Thomas Chou]

Hi Simon,

On 2015?12?14? 12:36, Simon Glass wrote:
> In very very space-constrained devices even the full UART driver is too
> large. In this case the debug UART can still be used in some cases.
>
> Add options to enable the UART driver in SPL and U-Boot proper. Enable both
> options by default.
>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
>
>   drivers/serial/Kconfig         | 20 ++++++++++++++++++++
>   drivers/serial/serial-uclass.c |  2 ++
>   2 files changed, 22 insertions(+)
>
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index 1fc287e..04541c9 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -15,6 +15,26 @@ config REQUIRE_SERIAL_CONSOLE
>   	  during serial port initialization (default y). Set this to n on
>   	  boards which have no debug serial port whatsoever.
>
> +config SERIAL_PRESENT
> +	bool "Provide a serial driver"
> +	depends on DM_SERIAL
> +	default y
> +	help
> +	  In very space-constrained devices even the full UART driver is too
> +	  large. In this case the debug UART can still be used in some cases.
> +	  This option enables the full UART in U-Boot, so if is it disabled,
> +	  the full UART driver will be omitted, thus saving space.
> +
> +config SPL_SERIAL_PRESENT
> +	bool "Provide a serial driver in SPL"
> +	depends on DM_SERIAL
> +	default y
> +	help
> +	  In very space-constrained devices even the full UART driver is too
> +	  large. In this case the debug UART can still be used in some cases.
> +	  This option enables the full UART in SPL, so if is it disabled,
> +	  the full UART driver will be omitted, thus saving space.
> +
>   config DM_SERIAL
>   	bool "Enable Driver Model for serial drivers"
>   	depends on DM
> diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
> index 4bf9a5c..95c3b91 100644
> --- a/drivers/serial/serial-uclass.c
> +++ b/drivers/serial/serial-uclass.c
> @@ -287,6 +287,7 @@ static int on_baudrate(const char *name, const char *value, enum env_op op,
>   }
>   U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
>
> +#if CONFIG_IS_ENABLED(SERIAL_PRESENT)
>   static int serial_post_probe(struct udevice *dev)
>   {
>   	struct dm_serial_ops *ops = serial_get_ops(dev);
> @@ -356,3 +357,4 @@ UCLASS_DRIVER(serial) = {
>   	.pre_remove	= serial_pre_remove,
>   	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
>   };
> +#endif
>

Reviewed-by: Thomas Chou <thomas@wytron.com.tw>

[U-Boot] [PATCH 2/3] dm: ns16550: Allow the driver to be omitted if requested

[Thomas Chou]

Hi Simon,

On 2015?12?14? 12:36, Simon Glass wrote:
> Allow the ns16550 debug UART to be used without the full driver.
>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
>
>   drivers/serial/ns16550.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
> index 3fab3f1..2025423 100644
> --- a/drivers/serial/ns16550.c
> +++ b/drivers/serial/ns16550.c
> @@ -440,6 +440,7 @@ static const struct udevice_id ns16550_serial_ids[] = {
>   };
>   #endif
>
> +#if CONFIG_IS_ENABLED(SERIAL_PRESENT)
>   U_BOOT_DRIVER(ns16550_serial) = {
>   	.name	= "ns16550_serial",
>   	.id	= UCLASS_SERIAL,
> @@ -453,4 +454,5 @@ U_BOOT_DRIVER(ns16550_serial) = {
>   	.ops	= &ns16550_serial_ops,
>   	.flags	= DM_FLAG_PRE_RELOC,
>   };
> +#endif
>   #endif /* CONFIG_DM_SERIAL */
>

Reviewed-by: Thomas Chou <thomas@wytron.com.tw>

[U-Boot] [PATCH 3/3] rockchip: Use the debug UART on rk3036

[Thomas Chou]

Hi Simon,

On 2015?12?14? 12:37, Simon Glass wrote:
> Rather than using a new debug UART implementation, use the standard one
> provided by U-Boot.
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
>
>   arch/arm/mach-rockchip/Makefile           |  1 -
>   arch/arm/mach-rockchip/rk3036-board-spl.c |  9 ++++-
>   arch/arm/mach-rockchip/rk_early_print.c   | 63 -------------------------------
>   configs/evb-rk3036_defconfig              |  6 +++
>   include/configs/rk3036_common.h           |  2 +
>   5 files changed, 16 insertions(+), 65 deletions(-)
>   delete mode 100644 arch/arm/mach-rockchip/rk_early_print.c
>
> diff --git a/arch/arm/mach-rockchip/Makefile b/arch/arm/mach-rockchip/Makefile
> index b703c3c..1cc4a96 100644
> --- a/arch/arm/mach-rockchip/Makefile
> +++ b/arch/arm/mach-rockchip/Makefile
> @@ -11,7 +11,6 @@ else
>   obj-$(CONFIG_ROCKCHIP_RK3288) += board.o
>   endif
>   obj-y += rk_timer.o
> -obj-y += rk_early_print.o
>   obj-$(CONFIG_$(SPL_)ROCKCHIP_COMMON) += common.o
>   obj-$(CONFIG_ROCKCHIP_RK3288) += rk3288/
>   obj-$(CONFIG_ROCKCHIP_RK3036) += rk3036/
> diff --git a/arch/arm/mach-rockchip/rk3036-board-spl.c b/arch/arm/mach-rockchip/rk3036-board-spl.c
> index 3a1491c..8015481 100644
> --- a/arch/arm/mach-rockchip/rk3036-board-spl.c
> +++ b/arch/arm/mach-rockchip/rk3036-board-spl.c
> @@ -5,6 +5,7 @@
>    */
>
>   #include <common.h>
> +#include <debug_uart.h>
>   #include <asm/io.h>
>   #include <asm/arch/grf_rk3036.h>
>   #include <asm/arch/hardware.h>
> @@ -34,7 +35,7 @@ void board_init_f(ulong dummy)
>   		     GPIO1C2_MASK << GPIO1C2_SHIFT,
>   		     GPIO1C3_UART2_SOUT << GPIO1C3_SHIFT |
>   		     GPIO1C2_UART2_SIN << GPIO1C2_SHIFT);
> -	rk_uart_init((void *)DEBUG_UART_BASE);
> +	debug_uart_init();
>   #endif
>   	rockchip_timer_init();
>   	sdram_init();
> @@ -53,3 +54,9 @@ void board_init_r(gd_t *id, ulong dest_addr)
>   	while (1)
>   		;
>   }
> +
> +void hang(void)
> +{
> +	while (1)
> +		;
> +}
> diff --git a/arch/arm/mach-rockchip/rk_early_print.c b/arch/arm/mach-rockchip/rk_early_print.c
> deleted file mode 100644
> index a1c14b0..0000000
> --- a/arch/arm/mach-rockchip/rk_early_print.c
> +++ /dev/null
> @@ -1,63 +0,0 @@
> -/*
> - * (C) Copyright 2015 Rockchip Electronics Co., Ltd
> - *
> - * SPDX-License-Identifier:     GPL-2.0+
> - */
> -
> -#include <asm/io.h>
> -#include <asm/arch/uart.h>
> -#include <common.h>
> -
> -static struct rk_uart *uart_ptr;
> -
> -static void uart_wrtie_byte(char byte)
> -{
> -	writel(byte, &uart_ptr->rbr);
> -	while (!(readl(&uart_ptr->lsr) & 0x40))
> -		;
> -}
> -
> -void print(char *s)
> -{
> -	while (*s) {
> -		if (*s == '\n')
> -			uart_wrtie_byte('\r');
> -	    uart_wrtie_byte(*s);
> -	    s++;
> -	}
> -}
> -
> -void print_hex(unsigned int n)
> -{
> -	int i;
> -	int temp;
> -
> -	uart_wrtie_byte('0');
> -	uart_wrtie_byte('x');
> -
> -	for (i = 8; i > 0; i--) {
> -		temp = (n >> (i - 1) * 4) & 0x0f;
> -		if (temp < 10)
> -			uart_wrtie_byte((char)(temp + '0'));
> -		else
> -			uart_wrtie_byte((char)(temp - 10 + 'a'));
> -	}
> -	uart_wrtie_byte('\n');
> -	uart_wrtie_byte('\r');
> -}
> -
> -/*
> - * TODO: since rk3036 only 4K sram to use in SPL, for saving space,
> - * we implement uart driver this way, we should convert this to use
> - * ns16550 driver in future, which support DEBUG_UART in the standard way
> - */
> -void rk_uart_init(void *base)
> -{
> -	uart_ptr = (struct rk_uart *)base;
> -	writel(0x83, &uart_ptr->lcr);
> -	writel(0x0d, &uart_ptr->rbr);
> -	writel(0x03, &uart_ptr->lcr);
> -
> -	/* fifo enable, sfe is shadow register of FCR[0] */
> -	writel(0x01, &uart_ptr->sfe);
> -}
> diff --git a/configs/evb-rk3036_defconfig b/configs/evb-rk3036_defconfig
> index 2e915ff..c196bd6 100644
> --- a/configs/evb-rk3036_defconfig
> +++ b/configs/evb-rk3036_defconfig
> @@ -24,3 +24,9 @@ CONFIG_DM_MMC=y
>   CONFIG_USE_PRIVATE_LIBGCC=y
>   CONFIG_CMD_DHRYSTONE=y
>   CONFIG_ERRNO_STR=y
> +CONFIG_DEBUG_UART=y
> +CONFIG_DEBUG_UART_NS16550=y
> +CONFIG_DEBUG_UART_BASE=0x20068000
> +CONFIG_DEBUG_UART_CLOCK=24000000
> +CONFIG_DEBUG_UART_SHIFT=2
> +# CONFIG_SPL_SERIAL_PRESENT is not set
> diff --git a/include/configs/rk3036_common.h b/include/configs/rk3036_common.h
> index f753e68..d22ea74 100644
> --- a/include/configs/rk3036_common.h
> +++ b/include/configs/rk3036_common.h
> @@ -24,6 +24,8 @@
>   #define CONFIG_SYS_TIMER_BASE		0x200440a0 /* TIMER5 */
>   #define CONFIG_SYS_TIMER_COUNTER	(CONFIG_SYS_TIMER_BASE + 8)
>
> +#define CONFIG_SPL_SERIAL_SUPPORT
> +
>   #define CONFIG_SYS_NS16550
>   #define CONFIG_SYS_NS16550_MEM32
>
>

Reviewed-by: Thomas Chou <thomas@wytron.com.tw>

[U-Boot] [PATCH 0/3] rockchip: Use the standard debug UART on rockchip

[Simon Glass]

HI Lin,

On 13 December 2015 at 23:26, hl <hl@rock-chips.com> wrote:
> Hi Simon.
>
>     Thank you for updating this series patch, i have verified it in
> evb-rk3036 board,
> it worked.
>

Great, thanks!
>
>
> On 14/12/15 12:36, Simon Glass wrote:
>>
>> The RK3036 has only 8KB of RAM available for SPL. At present it uses its
>> own
>> debug UART code.
>>
>> By allowing the ns16550 driver to provide a debug UART without providing a
>> full serial driver, we can enable a UART with a very small overhead. This
>> requires addition Kconfig options. The debug UART supports printhex8(),
>> printascii() and a few other functions.
>>
>> The root driver and uclass are pulled in by this series, but their size is
>> very small. It would possible to drop these by disabling CONFIG_DM_SERIAL.
>> However the ns16550 driver makes this hard, due to it supporting operation
>> without driver model, and operating differently in this case.
>>
>>
>> Simon Glass (3):
>>    dm: serial: Allow the UART driver to be dropped from the image
>>    dm: ns16550: Allow the driver to be omitted if requested
>>    rockchip: Use the debug UART on rk3036
>>
>>   arch/arm/mach-rockchip/Makefile           |  1 -
>>   arch/arm/mach-rockchip/rk3036-board-spl.c |  9 ++++-
>>   arch/arm/mach-rockchip/rk_early_print.c   | 63
>> -------------------------------
>>   configs/evb-rk3036_defconfig              |  6 +++
>>   drivers/serial/Kconfig                    | 20 ++++++++++
>>   drivers/serial/ns16550.c                  |  2 +
>>   drivers/serial/serial-uclass.c            |  2 +
>>   include/configs/rk3036_common.h           |  2 +
>>   8 files changed, 40 insertions(+), 65 deletions(-)
>>   delete mode 100644 arch/arm/mach-rockchip/rk_early_print.c
>>
>
> --
> Lin Huang
>
>

Regards,
Simon

[U-Boot] [PATCH 1/3] dm: serial: Allow the UART driver to be dropped from the image

[Simon Glass]

On 13 December 2015 at 21:36, Simon Glass <sjg@chromium.org> wrote:
> In very very space-constrained devices even the full UART driver is too
> large. In this case the debug UART can still be used in some cases.
>
> Add options to enable the UART driver in SPL and U-Boot proper. Enable both
> options by default.
>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
>
>  drivers/serial/Kconfig         | 20 ++++++++++++++++++++
>  drivers/serial/serial-uclass.c |  2 ++
>  2 files changed, 22 insertions(+)
>
[snip]

Due to a build warning, added an #ifdef around serial_stub_putc() for
cm_t43, and:

Applied to u-boot-dm/next.

[U-Boot] [PATCH 2/3] dm: ns16550: Allow the driver to be omitted if requested

[Simon Glass]

Applied to u-boot-dm/next.

[U-Boot] [PATCH 3/3] rockchip: Use the debug UART on rk3036

[Simon Glass]

Applied to u-boot-dm/next.