[U-Boot] [PATCH] serial: add BCM283x mini UART driver
The RPi3 typically uses the regular UART for high-speed communication with the Bluetooth device, leaving us the mini UART to use for the serial console. Add support for this UART so we can use it.
Signed-off-by: Stephen Warren swarren@wwwdotorg.org --- (This will be a dependency for the RPi 3 patches, so it'd be good if it could make it into mainline pretty quickly if acceptable.)
drivers/serial/Makefile | 1 + drivers/serial/serial_bcm283x_mu.c | 138 +++++++++++++++++++++++++++ include/dm/platform_data/serial_bcm283x_mu.h | 22 +++++ 3 files changed, 161 insertions(+) create mode 100644 drivers/serial/serial_bcm283x_mu.c create mode 100644 include/dm/platform_data/serial_bcm283x_mu.h
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile index 05bdf56c6fe9..ee7147a77abc 100644 --- a/drivers/serial/Makefile +++ b/drivers/serial/Makefile @@ -38,6 +38,7 @@ obj-$(CONFIG_UNIPHIER_SERIAL) += serial_uniphier.o obj-$(CONFIG_STM32_SERIAL) += serial_stm32.o obj-$(CONFIG_PIC32_SERIAL) += serial_pic32.o obj-$(CONFIG_STM32X7_SERIAL) += serial_stm32x7.o +obj-$(CONFIG_BCM283X_MU_SERIAL) += serial_bcm283x_mu.o
ifndef CONFIG_SPL_BUILD obj-$(CONFIG_USB_TTY) += usbtty.o diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c new file mode 100644 index 000000000000..97b57cc52163 --- /dev/null +++ b/drivers/serial/serial_bcm283x_mu.c @@ -0,0 +1,138 @@ +/* + * (C) Copyright 2016 Stephen Warren swarren@wwwdotorg.org + * + * Derived from pl01x code: + * + * (C) Copyright 2000 + * Rob Taylor, Flying Pig Systems. robt@flyingpig.com. + * + * (C) Copyright 2004 + * ARM Ltd. + * Philippe Robin, philippe.robin@arm.com + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +/* Simple U-Boot driver for the BCM283x mini UART */ + +#include <common.h> +#include <dm.h> +#include <errno.h> +#include <watchdog.h> +#include <asm/io.h> +#include <serial.h> +#include <dm/platform_data/serial_bcm283x_mu.h> +#include <linux/compiler.h> +#include <fdtdec.h> + +struct bcm283x_mu_regs { + u32 io; + u32 iir; + u32 ier; + u32 lcr; + u32 mcr; + u32 lsr; + u32 msr; + u32 scratch; + u32 cntl; + u32 stat; + u32 baud; +}; + +#define BCM283X_MU_LCR_DATA_SIZE_8 3 + +#define BCM283X_MU_LSR_TX_IDLE BIT(6) +/* This actually means not full, but is named not empty in the docs */ +#define BCM283X_MU_LSR_TX_EMPTY BIT(5) +#define BCM283X_MU_LSR_RX_READY BIT(0) + +struct bcm283x_mu_priv { + struct bcm283x_mu_regs *regs; +}; + +static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) +{ + struct bcm283x_mu_priv *priv = dev_get_priv(dev); + struct bcm283x_mu_regs *regs = priv->regs; + /* FIXME: Get this from plat data later */ + u32 clock_rate = 250000000; + u32 divider; + + divider = clock_rate / (baudrate * 8); + + writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr); + writel(divider - 1, ®s->baud); + + return 0; +} + +static int bcm283x_mu_serial_probe(struct udevice *dev) +{ + struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); + struct bcm283x_mu_priv *priv = dev_get_priv(dev); + + priv->regs = (struct bcm283x_mu_regs *)plat->base; + + return 0; +} + +static int bcm283x_mu_serial_getc(struct udevice *dev) +{ + struct bcm283x_mu_priv *priv = dev_get_priv(dev); + struct bcm283x_mu_regs *regs = priv->regs; + u32 data; + + /* Wait until there is data in the FIFO */ + if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY)) + return -EAGAIN; + + data = readl(®s->io); + + return (int)data; +} + +static int bcm283x_mu_serial_putc(struct udevice *dev, const char data) +{ + struct bcm283x_mu_priv *priv = dev_get_priv(dev); + struct bcm283x_mu_regs *regs = priv->regs; + + /* Wait until there is space in the FIFO */ + if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY)) + return -EAGAIN; + + /* Send the character */ + writel(data, ®s->io); + + return 0; +} + +static int bcm283x_mu_serial_pending(struct udevice *dev, bool input) +{ + struct bcm283x_mu_priv *priv = dev_get_priv(dev); + struct bcm283x_mu_regs *regs = priv->regs; + unsigned int lsr = readl(®s->lsr); + + if (input) { + WATCHDOG_RESET(); + return lsr & BCM283X_MU_LSR_RX_READY; + } else { + return !(lsr & BCM283X_MU_LSR_TX_IDLE); + } +} + +static const struct dm_serial_ops bcm283x_mu_serial_ops = { + .putc = bcm283x_mu_serial_putc, + .pending = bcm283x_mu_serial_pending, + .getc = bcm283x_mu_serial_getc, + .setbrg = bcm283x_mu_serial_setbrg, +}; + +U_BOOT_DRIVER(serial_bcm283x_mu) = { + .name = "serial_bcm283x_mu", + .id = UCLASS_SERIAL, + .platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata), + .probe = bcm283x_mu_serial_probe, + .ops = &bcm283x_mu_serial_ops, + .flags = DM_FLAG_PRE_RELOC, + .priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv), +}; diff --git a/include/dm/platform_data/serial_bcm283x_mu.h b/include/dm/platform_data/serial_bcm283x_mu.h new file mode 100644 index 000000000000..441594579549 --- /dev/null +++ b/include/dm/platform_data/serial_bcm283x_mu.h @@ -0,0 +1,22 @@ +/* + * (C) Copyright 2016 Stephen Warren swarren@wwwdotorg.org + * + * Derived from pl01x code: + * Copyright (c) 2014 Google, Inc + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef __serial_bcm283x_mu_h +#define __serial_bcm283x_mu_h + +/* + *Information about a serial port + * + * @base: Register base address + */ +struct bcm283x_mu_serial_platdata { + unsigned long base; +}; + +#endif
Hi Stephen,
On 16 March 2016 at 21:46, Stephen Warren swarren@wwwdotorg.org wrote:
The RPi3 typically uses the regular UART for high-speed communication with the Bluetooth device, leaving us the mini UART to use for the serial console. Add support for this UART so we can use it.
Signed-off-by: Stephen Warren swarren@wwwdotorg.org
(This will be a dependency for the RPi 3 patches, so it'd be good if it could make it into mainline pretty quickly if acceptable.)
Reviewed-by: Simon Glass sjg@chromium.org
Not sure if this went in already. But see comment below.
drivers/serial/Makefile | 1 + drivers/serial/serial_bcm283x_mu.c | 138 +++++++++++++++++++++++++++ include/dm/platform_data/serial_bcm283x_mu.h | 22 +++++ 3 files changed, 161 insertions(+) create mode 100644 drivers/serial/serial_bcm283x_mu.c create mode 100644 include/dm/platform_data/serial_bcm283x_mu.h
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile index 05bdf56c6fe9..ee7147a77abc 100644 --- a/drivers/serial/Makefile +++ b/drivers/serial/Makefile @@ -38,6 +38,7 @@ obj-$(CONFIG_UNIPHIER_SERIAL) += serial_uniphier.o obj-$(CONFIG_STM32_SERIAL) += serial_stm32.o obj-$(CONFIG_PIC32_SERIAL) += serial_pic32.o obj-$(CONFIG_STM32X7_SERIAL) += serial_stm32x7.o +obj-$(CONFIG_BCM283X_MU_SERIAL) += serial_bcm283x_mu.o
ifndef CONFIG_SPL_BUILD obj-$(CONFIG_USB_TTY) += usbtty.o diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c new file mode 100644 index 000000000000..97b57cc52163 --- /dev/null +++ b/drivers/serial/serial_bcm283x_mu.c @@ -0,0 +1,138 @@ +/*
- (C) Copyright 2016 Stephen Warren swarren@wwwdotorg.org
- Derived from pl01x code:
- (C) Copyright 2000
- Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
- (C) Copyright 2004
- ARM Ltd.
- Philippe Robin, philippe.robin@arm.com
- SPDX-License-Identifier: GPL-2.0+
- */
+/* Simple U-Boot driver for the BCM283x mini UART */
+#include <common.h> +#include <dm.h> +#include <errno.h> +#include <watchdog.h> +#include <asm/io.h> +#include <serial.h> +#include <dm/platform_data/serial_bcm283x_mu.h> +#include <linux/compiler.h> +#include <fdtdec.h>
+struct bcm283x_mu_regs {
u32 io;u32 iir;u32 ier;u32 lcr;u32 mcr;u32 lsr;u32 msr;u32 scratch;u32 cntl;u32 stat;u32 baud;+};
+#define BCM283X_MU_LCR_DATA_SIZE_8 3
+#define BCM283X_MU_LSR_TX_IDLE BIT(6) +/* This actually means not full, but is named not empty in the docs */ +#define BCM283X_MU_LSR_TX_EMPTY BIT(5) +#define BCM283X_MU_LSR_RX_READY BIT(0)
+struct bcm283x_mu_priv {
struct bcm283x_mu_regs *regs;+};
+static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;/* FIXME: Get this from plat data later */
Or device tree?
u32 clock_rate = 250000000;u32 divider;divider = clock_rate / (baudrate * 8);writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr);writel(divider - 1, ®s->baud);return 0;+}
+static int bcm283x_mu_serial_probe(struct udevice *dev) +{
struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);struct bcm283x_mu_priv *priv = dev_get_priv(dev);priv->regs = (struct bcm283x_mu_regs *)plat->base;return 0;+}
+static int bcm283x_mu_serial_getc(struct udevice *dev) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;u32 data;/* Wait until there is data in the FIFO */if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY))return -EAGAIN;data = readl(®s->io);return (int)data;+}
+static int bcm283x_mu_serial_putc(struct udevice *dev, const char data) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;/* Wait until there is space in the FIFO */if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY))return -EAGAIN;/* Send the character */writel(data, ®s->io);return 0;+}
+static int bcm283x_mu_serial_pending(struct udevice *dev, bool input) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;unsigned int lsr = readl(®s->lsr);if (input) {WATCHDOG_RESET();return lsr & BCM283X_MU_LSR_RX_READY;} else {return !(lsr & BCM283X_MU_LSR_TX_IDLE);
These look like flags - be care to return 1 if there is an unknown number of characters, rather than (e.g. 4). The latter might cause the uclass to expect 4 characters to be present.
Suggest putting ? 1 : 0 or ? 0 : 1 on the end.
}+}
+static const struct dm_serial_ops bcm283x_mu_serial_ops = {
.putc = bcm283x_mu_serial_putc,.pending = bcm283x_mu_serial_pending,.getc = bcm283x_mu_serial_getc,.setbrg = bcm283x_mu_serial_setbrg,+};
+U_BOOT_DRIVER(serial_bcm283x_mu) = {
.name = "serial_bcm283x_mu",.id = UCLASS_SERIAL,.platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata),.probe = bcm283x_mu_serial_probe,.ops = &bcm283x_mu_serial_ops,.flags = DM_FLAG_PRE_RELOC,.priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv),+}; diff --git a/include/dm/platform_data/serial_bcm283x_mu.h b/include/dm/platform_data/serial_bcm283x_mu.h new file mode 100644 index 000000000000..441594579549 --- /dev/null +++ b/include/dm/platform_data/serial_bcm283x_mu.h @@ -0,0 +1,22 @@ +/*
- (C) Copyright 2016 Stephen Warren swarren@wwwdotorg.org
- Derived from pl01x code:
- Copyright (c) 2014 Google, Inc
- SPDX-License-Identifier: GPL-2.0+
- */
+#ifndef __serial_bcm283x_mu_h +#define __serial_bcm283x_mu_h
+/*
- *Information about a serial port
- @base: Register base address
- */
+struct bcm283x_mu_serial_platdata {
unsigned long base;+};
+#endif
2.7.3
Regards, Simon
On 04/09/2016 12:34 PM, Simon Glass wrote:
Hi Stephen,
On 16 March 2016 at 21:46, Stephen Warren swarren@wwwdotorg.org wrote:
The RPi3 typically uses the regular UART for high-speed communication with the Bluetooth device, leaving us the mini UART to use for the serial console. Add support for this UART so we can use it.
Signed-off-by: Stephen Warren swarren@wwwdotorg.org
(This will be a dependency for the RPi 3 patches, so it'd be good if it could make it into mainline pretty quickly if acceptable.)
Reviewed-by: Simon Glass sjg@chromium.org
Not sure if this went in already. But see comment below.
It has, but I can send a fix.
diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c
+static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;/* FIXME: Get this from plat data later */u32 clock_rate = 250000000;Or device tree?
Well even if DT were used on this platform, the code right here would get the clock rate from platform data. Now, whether the platform data came from a board file or was parsed from DT is another matter.
+static int bcm283x_mu_serial_pending(struct udevice *dev, bool input) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;unsigned int lsr = readl(®s->lsr);if (input) {WATCHDOG_RESET();return lsr & BCM283X_MU_LSR_RX_READY;} else {return !(lsr & BCM283X_MU_LSR_TX_IDLE);These look like flags - be care to return 1 if there is an unknown number of characters, rather than (e.g. 4). The latter might cause the uclass to expect 4 characters to be present.
Suggest putting ? 1 : 0 or ? 0 : 1 on the end.
Luckily BCM283X_MU_LSR_RX_READY is BIT(0) so there's no practical issue. A !! would make this more obvious at this point in the code though. Do you think that warrants a patch? The ! on the second return also ensure the correct return value.
On Sat, Apr 09, 2016 at 09:45:36PM -0600, Stephen Warren wrote:
On 04/09/2016 12:34 PM, Simon Glass wrote:
Hi Stephen,
On 16 March 2016 at 21:46, Stephen Warren swarren@wwwdotorg.org wrote:
The RPi3 typically uses the regular UART for high-speed communication with the Bluetooth device, leaving us the mini UART to use for the serial console. Add support for this UART so we can use it.
Signed-off-by: Stephen Warren swarren@wwwdotorg.org
(This will be a dependency for the RPi 3 patches, so it'd be good if it could make it into mainline pretty quickly if acceptable.)
Reviewed-by: Simon Glass sjg@chromium.org
Not sure if this went in already. But see comment below.
It has, but I can send a fix.
diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c
+static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;/* FIXME: Get this from plat data later */u32 clock_rate = 250000000;Or device tree?
Well even if DT were used on this platform, the code right here would get the clock rate from platform data. Now, whether the platform data came from a board file or was parsed from DT is another matter.
+static int bcm283x_mu_serial_pending(struct udevice *dev, bool input) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;unsigned int lsr = readl(®s->lsr);if (input) {WATCHDOG_RESET();return lsr & BCM283X_MU_LSR_RX_READY;} else {return !(lsr & BCM283X_MU_LSR_TX_IDLE);These look like flags - be care to return 1 if there is an unknown number of characters, rather than (e.g. 4). The latter might cause the uclass to expect 4 characters to be present.
Suggest putting ? 1 : 0 or ? 0 : 1 on the end.
Luckily BCM283X_MU_LSR_RX_READY is BIT(0) so there's no practical issue. A !! would make this more obvious at this point in the code though. Do you think that warrants a patch? The ! on the second return also ensure the correct return value.
I hate the '!!' operator, how bad would it be to spell things out in the code in a bit less compact way but such that the compiler will still optimize things well.
Hi Stephen,
On 9 April 2016 at 21:45, Stephen Warren swarren@wwwdotorg.org wrote:
On 04/09/2016 12:34 PM, Simon Glass wrote:
Hi Stephen,
On 16 March 2016 at 21:46, Stephen Warren swarren@wwwdotorg.org wrote:
The RPi3 typically uses the regular UART for high-speed communication with the Bluetooth device, leaving us the mini UART to use for the serial console. Add support for this UART so we can use it.
Signed-off-by: Stephen Warren swarren@wwwdotorg.org
(This will be a dependency for the RPi 3 patches, so it'd be good if it could make it into mainline pretty quickly if acceptable.)
Reviewed-by: Simon Glass sjg@chromium.org
Not sure if this went in already. But see comment below.
It has, but I can send a fix.
diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c
+static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;/* FIXME: Get this from plat data later */u32 clock_rate = 250000000;Or device tree?
Well even if DT were used on this platform, the code right here would get the clock rate from platform data. Now, whether the platform data came from a board file or was parsed from DT is another matter.
+static int bcm283x_mu_serial_pending(struct udevice *dev, bool input) +{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);struct bcm283x_mu_regs *regs = priv->regs;unsigned int lsr = readl(®s->lsr);if (input) {WATCHDOG_RESET();return lsr & BCM283X_MU_LSR_RX_READY;} else {return !(lsr & BCM283X_MU_LSR_TX_IDLE);These look like flags - be care to return 1 if there is an unknown number of characters, rather than (e.g. 4). The latter might cause the uclass to expect 4 characters to be present.
Suggest putting ? 1 : 0 or ? 0 : 1 on the end.
Luckily BCM283X_MU_LSR_RX_READY is BIT(0) so there's no practical issue. A !! would make this more obvious at this point in the code though. Do you think that warrants a patch? The ! on the second return also ensure the correct return value.
I think it is worth a patch, in case perhaps someone else copies that code later. Agreed not a high priority though.
Regards, Simon
participants (3)
-
Simon Glass -
Stephen Warren -
Tom Rini