diff mbox series

[08/18] serial: add uart driver for MediaTek MT7620 SoC

Message ID 1602833759-19379-1-git-send-email-weijie.gao@mediatek.com
State Superseded
Delegated to: Daniel Schwierzeck
Headers show
Series [01/18] mips: dts: switch to board defines for dtb for mtmips | expand

Commit Message

Weijie Gao Oct. 16, 2020, 7:35 a.m. UTC
This patch adds uart support for MediaTek MT7620 and earlier SoCs.

The UART used by MT7620 is incompatible with the ns16550a driver.
All registers of this UART have different addresses. A special 16-bit
register for Divisor Latch is used to set the baudrate instead of the
original two 8-bit registers (DLL and DLM).

The driver can be built without DM which is useful for tiny SPL.

Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
---
 drivers/serial/Kconfig         |  20 ++
 drivers/serial/Makefile        |   1 +
 drivers/serial/serial.c        |   2 +
 drivers/serial/serial_mt7620.c | 350 +++++++++++++++++++++++++++++++++
 4 files changed, 373 insertions(+)
 create mode 100644 drivers/serial/serial_mt7620.c

Comments

Simon Glass Oct. 27, 2020, 4:51 a.m. UTC | #1
Hi Weijie,

On Fri, 16 Oct 2020 at 01:36, Weijie Gao <weijie.gao@mediatek.com> wrote:
>
> This patch adds uart support for MediaTek MT7620 and earlier SoCs.
>
> The UART used by MT7620 is incompatible with the ns16550a driver.
> All registers of this UART have different addresses. A special 16-bit
> register for Divisor Latch is used to set the baudrate instead of the
> original two 8-bit registers (DLL and DLM).
>
> The driver can be built without DM which is useful for tiny SPL.
>
> Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
> ---
>  drivers/serial/Kconfig         |  20 ++
>  drivers/serial/Makefile        |   1 +
>  drivers/serial/serial.c        |   2 +
>  drivers/serial/serial_mt7620.c | 350 +++++++++++++++++++++++++++++++++
>  4 files changed, 373 insertions(+)
>  create mode 100644 drivers/serial/serial_mt7620.c

Why do you need to build without DM? We have of-platdata which
provides for smaller images. What is the SRAM size available?

Regards,
Simon
Weijie Gao Oct. 29, 2020, 9:47 a.m. UTC | #2
On Mon, 2020-10-26 at 22:51 -0600, Simon Glass wrote:
> Hi Weijie,
> 
> On Fri, 16 Oct 2020 at 01:36, Weijie Gao <weijie.gao@mediatek.com> wrote:
> >
> > This patch adds uart support for MediaTek MT7620 and earlier SoCs.
> >
> > The UART used by MT7620 is incompatible with the ns16550a driver.
> > All registers of this UART have different addresses. A special 16-bit
> > register for Divisor Latch is used to set the baudrate instead of the
> > original two 8-bit registers (DLL and DLM).
> >
> > The driver can be built without DM which is useful for tiny SPL.
> >
> > Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
> > ---
> >  drivers/serial/Kconfig         |  20 ++
> >  drivers/serial/Makefile        |   1 +
> >  drivers/serial/serial.c        |   2 +
> >  drivers/serial/serial_mt7620.c | 350 +++++++++++++++++++++++++++++++++
> >  4 files changed, 373 insertions(+)
> >  create mode 100644 drivers/serial/serial_mt7620.c
> 
> Why do you need to build without DM? We have of-platdata which
> provides for smaller images. What is the SRAM size available?
> 

Actually it's the total size (spl+u-boot-lzma.img) that matters.
mt7620_rfb_defconfig is configured to be compatible with the original
u-boot from MTK SDK, and the maximum size is 192KiB.

Currently without SPL_DM, the final image u-boot-with-spl.bin is about
170KiB, the u-boot-spl.bin is only 20KiB.

If SPL_DM is enabled, the total size is 189KiB, which is very close to
the limit 192KiB, and the size of spl is almost doubled, 39KiB.
(Without DM, only serial_mt7620 is needed. However with DM, both
serial_mt7620, clk-mt7620 and misc are needed)

Considering that we may still add some feature to mt7620_rfb_defconfig
in the future, only 3KiB left is not enough. Building without DM is
apparently better.

I believe using of-platdata can only reduce few KiBs of SPL, because the
DM itself is the largest overhead.

> Regards,
> Simon
Simon Glass Oct. 29, 2020, 2:30 p.m. UTC | #3
Hi Weijie,

On Thu, 29 Oct 2020 at 03:47, Weijie Gao <weijie.gao@mediatek.com> wrote:
>
> On Mon, 2020-10-26 at 22:51 -0600, Simon Glass wrote:
> > Hi Weijie,
> >
> > On Fri, 16 Oct 2020 at 01:36, Weijie Gao <weijie.gao@mediatek.com> wrote:
> > >
> > > This patch adds uart support for MediaTek MT7620 and earlier SoCs.
> > >
> > > The UART used by MT7620 is incompatible with the ns16550a driver.
> > > All registers of this UART have different addresses. A special 16-bit
> > > register for Divisor Latch is used to set the baudrate instead of the
> > > original two 8-bit registers (DLL and DLM).
> > >
> > > The driver can be built without DM which is useful for tiny SPL.
> > >
> > > Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
> > > ---
> > >  drivers/serial/Kconfig         |  20 ++
> > >  drivers/serial/Makefile        |   1 +
> > >  drivers/serial/serial.c        |   2 +
> > >  drivers/serial/serial_mt7620.c | 350 +++++++++++++++++++++++++++++++++
> > >  4 files changed, 373 insertions(+)
> > >  create mode 100644 drivers/serial/serial_mt7620.c
> >
> > Why do you need to build without DM? We have of-platdata which
> > provides for smaller images. What is the SRAM size available?
> >
>
> Actually it's the total size (spl+u-boot-lzma.img) that matters.
> mt7620_rfb_defconfig is configured to be compatible with the original
> u-boot from MTK SDK, and the maximum size is 192KiB.

What is lzma.img ?

>
> Currently without SPL_DM, the final image u-boot-with-spl.bin is about
> 170KiB, the u-boot-spl.bin is only 20KiB.

That is definitely huge.

> If SPL_DM is enabled, the total size is 189KiB, which is very close to
> the limit 192KiB, and the size of spl is almost doubled, 39KiB.
> (Without DM, only serial_mt7620 is needed. However with DM, both
> serial_mt7620, clk-mt7620 and misc are needed)
>
> Considering that we may still add some feature to mt7620_rfb_defconfig
> in the future, only 3KiB left is not enough. Building without DM is
> apparently better.
>
> I believe using of-platdata can only reduce few KiBs of SPL, because the
> DM itself is the largest overhead.

That's not my experience. The core DM overhead is fairly small,
perhaps 3-4KB. The device tree itself is typically at least another
3KB, depending on how many nodes you mark for inclusion in SPL.

With of-platdata the overhead of DM is not that terrible. You can see
some stats here:

http://u-boot.10912.n7.nabble.com/RFC-PATCH-v2-0-3-RFC-tiny-dm-Proposal-for-using-driver-model-in-SPL-td418552.html

Regards,
SImon
Weijie Gao Oct. 30, 2020, 3:20 a.m. UTC | #4
On Thu, 2020-10-29 at 08:30 -0600, Simon Glass wrote:
> Hi Weijie,
> 
> On Thu, 29 Oct 2020 at 03:47, Weijie Gao <weijie.gao@mediatek.com> wrote:
> >
> > On Mon, 2020-10-26 at 22:51 -0600, Simon Glass wrote:
> > > Hi Weijie,
> > >
> > > On Fri, 16 Oct 2020 at 01:36, Weijie Gao <weijie.gao@mediatek.com> wrote:
> > > >
> > > > This patch adds uart support for MediaTek MT7620 and earlier SoCs.
> > > >
> > > > The UART used by MT7620 is incompatible with the ns16550a driver.
> > > > All registers of this UART have different addresses. A special 16-bit
> > > > register for Divisor Latch is used to set the baudrate instead of the
> > > > original two 8-bit registers (DLL and DLM).
> > > >
> > > > The driver can be built without DM which is useful for tiny SPL.
> > > >
> > > > Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
> > > > ---
> > > >  drivers/serial/Kconfig         |  20 ++
> > > >  drivers/serial/Makefile        |   1 +
> > > >  drivers/serial/serial.c        |   2 +
> > > >  drivers/serial/serial_mt7620.c | 350 +++++++++++++++++++++++++++++++++
> > > >  4 files changed, 373 insertions(+)
> > > >  create mode 100644 drivers/serial/serial_mt7620.c
> > >
> > > Why do you need to build without DM? We have of-platdata which
> > > provides for smaller images. What is the SRAM size available?
> > >
> >
> > Actually it's the total size (spl+u-boot-lzma.img) that matters.
> > mt7620_rfb_defconfig is configured to be compatible with the original
> > u-boot from MTK SDK, and the maximum size is 192KiB.
> 
> What is lzma.img ?

The u-boot.bin is compressed to reduce it's size (395KiB -> 150KiB), and
the SPL is responsible to decompress it.

> 
> >
> > Currently without SPL_DM, the final image u-boot-with-spl.bin is about
> > 170KiB, the u-boot-spl.bin is only 20KiB.
> 
> That is definitely huge.

Without the decompression code, the size of SPL will be reduced to 9KiB.

> 
> > If SPL_DM is enabled, the total size is 189KiB, which is very close to
> > the limit 192KiB, and the size of spl is almost doubled, 39KiB.
> > (Without DM, only serial_mt7620 is needed. However with DM, both
> > serial_mt7620, clk-mt7620 and misc are needed)
> >
> > Considering that we may still add some feature to mt7620_rfb_defconfig
> > in the future, only 3KiB left is not enough. Building without DM is
> > apparently better.
> >
> > I believe using of-platdata can only reduce few KiBs of SPL, because the
> > DM itself is the largest overhead.
> 
> That's not my experience. The core DM overhead is fairly small,
> perhaps 3-4KB. The device tree itself is typically at least another
> 3KB, depending on how many nodes you mark for inclusion in SPL.
> 
> With of-platdata the overhead of DM is not that terrible. You can see
> some stats here:

I have tried to optimize drivers and configs used in SPL, and managed to
reduce the size of SPL to 22KiB with of-platdata (without DM, the size
is 17KiB. So it's only 5KiB used by DM).

I'll switch this driver to of-platdata in the next series.

> 
> http://u-boot.10912.n7.nabble.com/RFC-PATCH-v2-0-3-RFC-tiny-dm-Proposal-for-using-driver-model-in-SPL-td418552.html
> 
> Regards,
> SImon
Simon Glass Oct. 30, 2020, 6:15 p.m. UTC | #5
Hi Weijie,

On Thu, 29 Oct 2020 at 21:21, Weijie Gao <weijie.gao@mediatek.com> wrote:
>
> On Thu, 2020-10-29 at 08:30 -0600, Simon Glass wrote:
> > Hi Weijie,
> >
> > On Thu, 29 Oct 2020 at 03:47, Weijie Gao <weijie.gao@mediatek.com> wrote:
> > >
> > > On Mon, 2020-10-26 at 22:51 -0600, Simon Glass wrote:
> > > > Hi Weijie,
> > > >
> > > > On Fri, 16 Oct 2020 at 01:36, Weijie Gao <weijie.gao@mediatek.com> wrote:
> > > > >
> > > > > This patch adds uart support for MediaTek MT7620 and earlier SoCs.
> > > > >
> > > > > The UART used by MT7620 is incompatible with the ns16550a driver.
> > > > > All registers of this UART have different addresses. A special 16-bit
> > > > > register for Divisor Latch is used to set the baudrate instead of the
> > > > > original two 8-bit registers (DLL and DLM).
> > > > >
> > > > > The driver can be built without DM which is useful for tiny SPL.
> > > > >
> > > > > Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
> > > > > ---
> > > > >  drivers/serial/Kconfig         |  20 ++
> > > > >  drivers/serial/Makefile        |   1 +
> > > > >  drivers/serial/serial.c        |   2 +
> > > > >  drivers/serial/serial_mt7620.c | 350 +++++++++++++++++++++++++++++++++
> > > > >  4 files changed, 373 insertions(+)
> > > > >  create mode 100644 drivers/serial/serial_mt7620.c
> > > >
> > > > Why do you need to build without DM? We have of-platdata which
> > > > provides for smaller images. What is the SRAM size available?
> > > >
> > >
> > > Actually it's the total size (spl+u-boot-lzma.img) that matters.
> > > mt7620_rfb_defconfig is configured to be compatible with the original
> > > u-boot from MTK SDK, and the maximum size is 192KiB.
> >
> > What is lzma.img ?
>
> The u-boot.bin is compressed to reduce it's size (395KiB -> 150KiB), and
> the SPL is responsible to decompress it.
>
> >
> > >
> > > Currently without SPL_DM, the final image u-boot-with-spl.bin is about
> > > 170KiB, the u-boot-spl.bin is only 20KiB.
> >
> > That is definitely huge.
>
> Without the decompression code, the size of SPL will be reduced to 9KiB.

OK...so is it possible to have SPL load U-Boot, instead of including
it in SRAM? That is normally what is done.

>
> >
> > > If SPL_DM is enabled, the total size is 189KiB, which is very close to
> > > the limit 192KiB, and the size of spl is almost doubled, 39KiB.
> > > (Without DM, only serial_mt7620 is needed. However with DM, both
> > > serial_mt7620, clk-mt7620 and misc are needed)
> > >
> > > Considering that we may still add some feature to mt7620_rfb_defconfig
> > > in the future, only 3KiB left is not enough. Building without DM is
> > > apparently better.
> > >
> > > I believe using of-platdata can only reduce few KiBs of SPL, because the
> > > DM itself is the largest overhead.
> >
> > That's not my experience. The core DM overhead is fairly small,
> > perhaps 3-4KB. The device tree itself is typically at least another
> > 3KB, depending on how many nodes you mark for inclusion in SPL.
> >
> > With of-platdata the overhead of DM is not that terrible. You can see
> > some stats here:
>
> I have tried to optimize drivers and configs used in SPL, and managed to
> reduce the size of SPL to 22KiB with of-platdata (without DM, the size
> is 17KiB. So it's only 5KiB used by DM).
>
> I'll switch this driver to of-platdata in the next series.

Gosh that was quick, nice work!

>
> >
> > http://u-boot.10912.n7.nabble.com/RFC-PATCH-v2-0-3-RFC-tiny-dm-Proposal-for-using-driver-model-in-SPL-td418552.html

Regards,
Simon
diff mbox series

Patch

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index b4805a2e4e..44fff8a3cd 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -401,6 +401,16 @@  config DEBUG_UART_MTK
 	  driver will be available until the real driver model serial is
 	  running.
 
+config DEBUG_UART_MT7620
+	bool "UART driver for MediaTek MT7620 and earlier SoCs"
+	depends on MT7620_SERIAL
+	help
+	  Select this to enable a debug UART using the UART driver for
+	  MediaTek MT7620 and earlier SoCs.
+	  You will need to provide parameters to make this work. The
+	  driver will be available until the real driver model serial is
+	  running.
+
 endchoice
 
 config DEBUG_UART_BASE
@@ -817,6 +827,16 @@  config MTK_SERIAL
 	  The High-speed UART is compatible with the ns16550a UART and have
 	  its own high-speed registers.
 
+config MT7620_SERIAL
+	bool "UART driver for MediaTek MT7620 and earlier SoCs"
+	depends on DM_SERIAL
+	help
+	  Select this to enable UART support for MediaTek MT7620 and earlier
+	  SoCs. This driver uses driver model and requires a device tree
+	  binding to operate.
+	  The UART driver for MediaTek MT7620 and earlier SoCs is *NOT*
+	  compatible with the ns16550a UART.
+
 config MPC8XX_CONS
 	bool "Console driver for MPC8XX"
 	depends on MPC8xx
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 25f7f8d342..0c3810f5d5 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -69,6 +69,7 @@  obj-$(CONFIG_NULLDEV_SERIAL) += serial_nulldev.o
 obj-$(CONFIG_OWL_SERIAL) += serial_owl.o
 obj-$(CONFIG_OMAP_SERIAL) += serial_omap.o
 obj-$(CONFIG_MTK_SERIAL) += serial_mtk.o
+obj-$(CONFIG_MT7620_SERIAL) += serial_mt7620.o
 obj-$(CONFIG_SIFIVE_SERIAL) += serial_sifive.o
 obj-$(CONFIG_XEN_SERIAL) += serial_xen.o
 
diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
index 53358acb81..312c591bf1 100644
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -127,6 +127,7 @@  serial_initfunc(pl01x_serial_initialize);
 serial_initfunc(pxa_serial_initialize);
 serial_initfunc(sh_serial_initialize);
 serial_initfunc(mtk_serial_initialize);
+serial_initfunc(mt7620_serial_initialize);
 
 /**
  * serial_register() - Register serial driver with serial driver core
@@ -181,6 +182,7 @@  int serial_initialize(void)
 	pxa_serial_initialize();
 	sh_serial_initialize();
 	mtk_serial_initialize();
+	mt7620_serial_initialize();
 
 	serial_assign(default_serial_console()->name);
 
diff --git a/drivers/serial/serial_mt7620.c b/drivers/serial/serial_mt7620.c
new file mode 100644
index 0000000000..af0919978f
--- /dev/null
+++ b/drivers/serial/serial_mt7620.c
@@ -0,0 +1,350 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * UART driver for MediaTek MT7620 and earlier SoCs
+ *
+ * Copyright (C) 2020 MediaTek Inc.
+ * Author: Weijie Gao <weijie.gao@mediatek.com>
+ */
+
+#include <clk.h>
+#include <div64.h>
+#include <dm.h>
+#include <errno.h>
+#include <log.h>
+#include <reset.h>
+#include <serial.h>
+#include <watchdog.h>
+#include <asm/io.h>
+#include <asm/types.h>
+#include <linux/err.h>
+
+struct mt7620_serial_regs {
+	u32 rbr;
+	u32 thr;
+	u32 ier;
+	u32 iir;
+	u32 fcr;
+	u32 lcr;
+	u32 mcr;
+	u32 lsr;
+	u32 msr;
+	u32 scratch;
+	u32 dl;
+	u32 dll;
+	u32 dlm;
+	u32 ifctl;
+};
+
+#define UART_LCR_WLS_8		0x03	/* 8 bit character length */
+
+#define UART_LSR_DR		0x01	/* Data ready */
+#define UART_LSR_THRE		0x20	/* Xmit holding register empty */
+#define UART_LSR_TEMT		0x40	/* Xmitter empty */
+
+#define UART_MCR_DTR		0x01	/* DTR */
+#define UART_MCR_RTS		0x02	/* RTS */
+
+#define UART_FCR_FIFO_EN	0x01	/* Fifo enable */
+#define UART_FCR_RXSR		0x02	/* Receiver soft reset */
+#define UART_FCR_TXSR		0x04	/* Transmitter soft reset */
+
+#define UART_MCRVAL (UART_MCR_DTR | \
+		     UART_MCR_RTS)
+
+/* Clear & enable FIFOs */
+#define UART_FCRVAL (UART_FCR_FIFO_EN | \
+		     UART_FCR_RXSR |	\
+		     UART_FCR_TXSR)
+
+struct mt7620_serial_priv {
+	struct mt7620_serial_regs __iomem *regs;
+	u32 clock;
+};
+
+static void _mt7620_serial_setbrg(struct mt7620_serial_priv *priv, int baud)
+{
+	u32 quot;
+
+	/* set divisor */
+	quot = DIV_ROUND_CLOSEST(priv->clock, 16 * baud);
+	writel(quot, &priv->regs->dl);
+
+	/* set character length and stop bits */
+	writel(UART_LCR_WLS_8, &priv->regs->lcr);
+}
+
+static int _mt7620_serial_putc(struct mt7620_serial_priv *priv, const char ch)
+{
+	if (!(readl(&priv->regs->lsr) & UART_LSR_THRE))
+		return -EAGAIN;
+
+	writel(ch, &priv->regs->thr);
+
+	if (ch == '\n')
+		WATCHDOG_RESET();
+
+	return 0;
+}
+
+static int _mt7620_serial_getc(struct mt7620_serial_priv *priv)
+{
+	if (!(readl(&priv->regs->lsr) & UART_LSR_DR))
+		return -EAGAIN;
+
+	return readl(&priv->regs->rbr);
+}
+
+static int _mt7620_serial_pending(struct mt7620_serial_priv *priv, bool input)
+{
+	if (input)
+		return (readl(&priv->regs->lsr) & UART_LSR_DR) ? 1 : 0;
+	else
+		return (readl(&priv->regs->lsr) & UART_LSR_THRE) ? 0 : 1;
+}
+
+#if defined(CONFIG_DM_SERIAL) && \
+	(!defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_DM))
+static int mt7620_serial_setbrg(struct udevice *dev, int baudrate)
+{
+	struct mt7620_serial_priv *priv = dev_get_priv(dev);
+
+	_mt7620_serial_setbrg(priv, baudrate);
+
+	return 0;
+}
+
+static int mt7620_serial_putc(struct udevice *dev, const char ch)
+{
+	struct mt7620_serial_priv *priv = dev_get_priv(dev);
+
+	return _mt7620_serial_putc(priv, ch);
+}
+
+static int mt7620_serial_getc(struct udevice *dev)
+{
+	struct mt7620_serial_priv *priv = dev_get_priv(dev);
+
+	return _mt7620_serial_getc(priv);
+}
+
+static int mt7620_serial_pending(struct udevice *dev, bool input)
+{
+	struct mt7620_serial_priv *priv = dev_get_priv(dev);
+
+	return _mt7620_serial_pending(priv, input);
+}
+
+static int mt7620_serial_probe(struct udevice *dev)
+{
+	struct mt7620_serial_priv *priv = dev_get_priv(dev);
+
+	/* Disable interrupt */
+	writel(0, &priv->regs->ier);
+
+	writel(UART_MCRVAL, &priv->regs->mcr);
+	writel(UART_FCRVAL, &priv->regs->fcr);
+
+	return 0;
+}
+
+static int mt7620_serial_ofdata_to_platdata(struct udevice *dev)
+{
+	struct mt7620_serial_priv *priv = dev_get_priv(dev);
+	struct reset_ctl reset_uart;
+	struct clk clk;
+	int err;
+
+	err = reset_get_by_index(dev, 0, &reset_uart);
+	if (!err)
+		reset_deassert(&reset_uart);
+
+	priv->regs = dev_remap_addr_index(dev, 0);
+	if (!priv->regs) {
+		dev_err(dev, "mt7620_serial: unable to map UART registers\n");
+		return -EINVAL;
+	}
+
+	err = clk_get_by_index(dev, 0, &clk);
+	if (!err) {
+		err = clk_get_rate(&clk);
+		if (!IS_ERR_VALUE(err))
+			priv->clock = err;
+	} else if (err != -ENOENT && err != -ENODEV && err != -ENOSYS) {
+		dev_err(dev, "mt7620_serial: failed to get clock\n");
+		return err;
+	}
+
+	if (!priv->clock)
+		priv->clock = dev_read_u32_default(dev, "clock-frequency", 0);
+
+	if (!priv->clock) {
+		dev_err(dev, "mt7620_serial: clock not defined\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct dm_serial_ops mt7620_serial_ops = {
+	.putc = mt7620_serial_putc,
+	.pending = mt7620_serial_pending,
+	.getc = mt7620_serial_getc,
+	.setbrg = mt7620_serial_setbrg,
+};
+
+static const struct udevice_id mt7620_serial_ids[] = {
+	{ .compatible = "mediatek,mt7620-uart" },
+	{ }
+};
+
+U_BOOT_DRIVER(serial_mt7620) = {
+	.name = "serial_mt7620",
+	.id = UCLASS_SERIAL,
+	.of_match = mt7620_serial_ids,
+	.ofdata_to_platdata = mt7620_serial_ofdata_to_platdata,
+	.priv_auto_alloc_size = sizeof(struct mt7620_serial_priv),
+	.probe = mt7620_serial_probe,
+	.ops = &mt7620_serial_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};
+#else
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define DECLARE_MT7620_UART_PRIV(port) \
+	static struct mt7620_serial_priv mt7620_uart##port = { \
+	.regs = (struct mt7620_serial_regs *)CONFIG_MT7620_UART##port##_BASE, \
+	.clock = CONFIG_MT7620_UART##port##_CLK \
+};
+
+#define DECLARE_MT7620_UART_FUNCTIONS(port) \
+	static int mt7620_serial##port##_init(void) \
+	{ \
+		writel(0, &mt7620_uart##port.regs->ier); \
+		writel(UART_MCRVAL, &mt7620_uart##port.regs->mcr); \
+		writel(UART_FCRVAL, &mt7620_uart##port.regs->fcr); \
+		_mt7620_serial_setbrg(&mt7620_uart##port, gd->baudrate); \
+		return 0 ; \
+	} \
+	static void mt7620_serial##port##_setbrg(void) \
+	{ \
+		_mt7620_serial_setbrg(&mt7620_uart##port, gd->baudrate); \
+	} \
+	static int mt7620_serial##port##_getc(void) \
+	{ \
+		int err; \
+		do { \
+			err = _mt7620_serial_getc(&mt7620_uart##port); \
+			if (err == -EAGAIN) \
+				WATCHDOG_RESET(); \
+		} while (err == -EAGAIN); \
+		return err >= 0 ? err : 0; \
+	} \
+	static int mt7620_serial##port##_tstc(void) \
+	{ \
+		return _mt7620_serial_pending(&mt7620_uart##port, true); \
+	} \
+	static void mt7620_serial##port##_putc(const char c) \
+	{ \
+		int err; \
+		if (c == '\n') \
+			mt7620_serial##port##_putc('\r'); \
+		do { \
+			err = _mt7620_serial_putc(&mt7620_uart##port, c); \
+		} while (err == -EAGAIN); \
+	} \
+	static void mt7620_serial##port##_puts(const char *s) \
+	{ \
+		while (*s) { \
+			mt7620_serial##port##_putc(*s++); \
+		} \
+	}
+
+/* Serial device descriptor */
+#define INIT_MT7620_UART_STRUCTURE(port, __name) {	\
+	.name	= __name,				\
+	.start	= mt7620_serial##port##_init,		\
+	.stop	= NULL,					\
+	.setbrg	= mt7620_serial##port##_setbrg,		\
+	.getc	= mt7620_serial##port##_getc,		\
+	.tstc	= mt7620_serial##port##_tstc,		\
+	.putc	= mt7620_serial##port##_putc,		\
+	.puts	= mt7620_serial##port##_puts,		\
+}
+
+#define DECLARE_MT7620_UART(port, __name) \
+	DECLARE_MT7620_UART_PRIV(port); \
+	DECLARE_MT7620_UART_FUNCTIONS(port); \
+	struct serial_device mt7620_uart##port##_device = \
+		INIT_MT7620_UART_STRUCTURE(port, __name);
+
+#if defined(CONFIG_MT7620_UART1_BASE) && defined(CONFIG_MT7620_UART1_CLK)
+DECLARE_MT7620_UART(1, "mt7620-uart0");
+#endif
+#if defined(CONFIG_MT7620_UART2_BASE) && defined(CONFIG_MT7620_UART2_CLK)
+DECLARE_MT7620_UART(2, "mt7620-uart1");
+#endif
+#if defined(CONFIG_MT7620_UART3_BASE) && defined(CONFIG_MT7620_UART3_CLK)
+DECLARE_MT7620_UART(3, "mt7620-uart2");
+#endif
+
+__weak struct serial_device *default_serial_console(void)
+{
+#if CONFIG_CONS_INDEX == 1
+	return &mt7620_uart1_device;
+#elif CONFIG_CONS_INDEX == 2
+	return &mt7620_uart2_device;
+#elif CONFIG_CONS_INDEX == 3
+	return &mt7620_uart3_device;
+#else
+#error "Bad CONFIG_CONS_INDEX."
+#endif
+}
+
+void mt7620_serial_initialize(void)
+{
+#if defined(CONFIG_MT7620_UART1_BASE) && defined(CONFIG_MT7620_UART1_CLK)
+	serial_register(&mt7620_uart1_device);
+#endif
+#if defined(CONFIG_MT7620_UART2_BASE) && defined(CONFIG_MT7620_UART2_CLK)
+	serial_register(&mt7620_uart2_device);
+#endif
+#if defined(CONFIG_MT7620_UART3_BASE) && defined(CONFIG_MT7620_UART3_CLK)
+	serial_register(&mt7620_uart3_device);
+#endif
+}
+
+#endif
+
+#ifdef CONFIG_DEBUG_UART_MT7620
+
+#include <debug_uart.h>
+
+static inline void _debug_uart_init(void)
+{
+	struct mt7620_serial_priv priv;
+
+	priv.regs = (void *)CONFIG_DEBUG_UART_BASE;
+	priv.clock = CONFIG_DEBUG_UART_CLOCK;
+
+	writel(0, &priv.regs->ier);
+	writel(UART_MCRVAL, &priv.regs->mcr);
+	writel(UART_FCRVAL, &priv.regs->fcr);
+
+	_mt7620_serial_setbrg(&priv, CONFIG_BAUDRATE);
+}
+
+static inline void _debug_uart_putc(int ch)
+{
+	struct mt7620_serial_regs __iomem *regs =
+		(void *)CONFIG_DEBUG_UART_BASE;
+
+	while (!(readl(&regs->lsr) & UART_LSR_THRE))
+		;
+
+	writel(ch, &regs->thr);
+}
+
+DEBUG_UART_FUNCS
+
+#endif