bcm2835_pl011_serial: Add BCM2835 specific serial driver

On bcm2835 we need to ensure we only access serial devices that are
muxed to the serial output pins of the pin header. To achieve this
for the pl011 device, add a bcm2835 specific pl011 wrapper device
that does this check but otherwise behaves like a pl011 device.

Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/MAINTAINERS b/MAINTAINERS
index dd24697f15acbacccd5b1137f474e5905b251ffe..0c7efde5a5b5cafb6c9866b786ad3899f8cb5963 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -99,6 +99,7 @@ F:    drivers/gpio/bcm2835_gpio.c
 F:     drivers/mmc/bcm2835_sdhci.c
 F:     drivers/mmc/bcm2835_sdhost.c
 F:     drivers/serial/serial_bcm283x_mu.c
+F:     drivers/serial/serial_bcm283x_pl011.c
 F:     drivers/video/bcm2835.c
 F:     include/dm/platform_data/serial_bcm283x_mu.h
 F:     drivers/pinctrl/broadcom/

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 72281a7b64ea6b56676a550b6cd1b5e82d211a5d..3ffedba525657ea587882562daa9c2b81dca8217 100644 (file)
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -395,6 +395,15 @@ config BCM283X_MU_SERIAL
        help
          Select this to enable Mini-UART support on BCM283X family of SoCs.
 
+config BCM283X_PL011_SERIAL
+       bool "Support for BCM283x PL011 UART"
+       depends on PL01X_SERIAL && ARCH_BCM283X
+       default y
+       help
+         Select this to enable an overriding PL011 driver for BCM283X SoCs
+         that supports automatic disable, so that it only gets used when
+         the UART is actually muxed.
+
 config BCM6345_SERIAL
        bool "Support for BCM6345 UART"
        depends on DM_SERIAL && ARCH_BMIPS

diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 5ef603ab1521c27f1261624762d9acc2ca47ff9a..cac9a8b31212f4a4fe34cdd732f6ea74a140bb39 100644 (file)
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_STI_ASC_SERIAL) += serial_sti_asc.o
 obj-$(CONFIG_PIC32_SERIAL) += serial_pic32.o
 obj-$(CONFIG_STM32_SERIAL) += serial_stm32.o
 obj-$(CONFIG_BCM283X_MU_SERIAL) += serial_bcm283x_mu.o
+obj-$(CONFIG_BCM283X_PL011_SERIAL) += serial_bcm283x_pl011.o
 obj-$(CONFIG_MSM_SERIAL) += serial_msm.o
 obj-$(CONFIG_MVEBU_A3700_UART) += serial_mvebu_a3700.o
 obj-$(CONFIG_MPC8XX_CONS) += serial_mpc8xx.o

diff --git a/drivers/serial/serial_bcm283x_pl011.c b/drivers/serial/serial_bcm283x_pl011.c
new file mode 100644 (file)
index 0000000..bfd39f8
--- /dev/null
+++ b/drivers/serial/serial_bcm283x_pl011.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2018 Alexander Graf <agraf@suse.de>
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/gpio.h>
+#include <dm/pinctrl.h>
+#include <dm/platform_data/serial_pl01x.h>
+#include "serial_pl01x_internal.h"
+
+/*
+ * Check if this serial device is muxed
+ *
+ * The serial device will only work properly if it has been muxed to the serial
+ * pins by firmware. Check whether that happened here.
+ *
+ * @return true if serial device is muxed, false if not
+ */
+static bool bcm283x_is_serial_muxed(void)
+{
+       int serial_gpio = 15;
+       struct udevice *dev;
+
+       if (uclass_first_device(UCLASS_PINCTRL, &dev) || !dev)
+               return false;
+
+       if (pinctrl_get_gpio_mux(dev, 0, serial_gpio) != BCM2835_GPIO_ALT0)
+               return false;
+
+       return true;
+}
+
+static int bcm283x_pl011_serial_ofdata_to_platdata(struct udevice *dev)
+{
+       struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
+       int ret;
+
+       /* Don't spawn the device if it's not muxed */
+       if (!bcm283x_is_serial_muxed())
+               return -ENODEV;
+
+       ret = pl01x_serial_ofdata_to_platdata(dev);
+       if (ret)
+               return ret;
+
+       /*
+        * TODO: Reinitialization doesn't always work for now, just skip
+        *       init always - we know we're already initialized
+        */
+       plat->skip_init = true;
+
+       return 0;
+}
+
+static const struct udevice_id bcm283x_pl011_serial_id[] = {
+       {.compatible = "brcm,bcm2835-pl011", .data = TYPE_PL011},
+       {}
+};
+
+U_BOOT_DRIVER(bcm283x_pl011_uart) = {
+       .name   = "bcm283x_pl011",
+       .id     = UCLASS_SERIAL,
+       .of_match = of_match_ptr(bcm283x_pl011_serial_id),
+       .ofdata_to_platdata = of_match_ptr(bcm283x_pl011_serial_ofdata_to_platdata),
+       .platdata_auto_alloc_size = sizeof(struct pl01x_serial_platdata),
+       .probe  = pl01x_serial_probe,
+       .ops    = &pl01x_serial_ops,
+       .flags  = DM_FLAG_PRE_RELOC,
+       .priv_auto_alloc_size = sizeof(struct pl01x_priv),
+};

diff --git a/drivers/serial/serial_pl01x.c b/drivers/serial/serial_pl01x.c
index 2cbc84c1b46aa50eec0f5a949fca182fe3a1e105..23d9d839cbc1c249af6e0556ff11dbb8e03d4740 100644 (file)
--- a/drivers/serial/serial_pl01x.c
+++ b/drivers/serial/serial_pl01x.c
@@ -273,11 +273,6 @@ __weak struct serial_device *default_serial_console(void)
 
 #ifdef CONFIG_DM_SERIAL
 
-struct pl01x_priv {
-       struct pl01x_regs *regs;
-       enum pl01x_type type;
-};
-
 static int pl01x_serial_setbrg(struct udevice *dev, int baudrate)
 {
        struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
@@ -291,7 +286,7 @@ static int pl01x_serial_setbrg(struct udevice *dev, int baudrate)
        return 0;
 }
 
-static int pl01x_serial_probe(struct udevice *dev)
+int pl01x_serial_probe(struct udevice *dev)
 {
        struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
        struct pl01x_priv *priv = dev_get_priv(dev);
@@ -329,7 +324,7 @@ static int pl01x_serial_pending(struct udevice *dev, bool input)
                return fr & UART_PL01x_FR_TXFF ? 0 : 1;
 }
 
-static const struct dm_serial_ops pl01x_serial_ops = {
+const struct dm_serial_ops pl01x_serial_ops = {
        .putc = pl01x_serial_putc,
        .pending = pl01x_serial_pending,
        .getc = pl01x_serial_getc,
@@ -343,7 +338,7 @@ static const struct udevice_id pl01x_serial_id[] ={
        {}
 };
 
-static int pl01x_serial_ofdata_to_platdata(struct udevice *dev)
+int pl01x_serial_ofdata_to_platdata(struct udevice *dev)
 {
        struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
        fdt_addr_t addr;

diff --git a/drivers/serial/serial_pl01x_internal.h b/drivers/serial/serial_pl01x_internal.h
index 288a4f19f56c2e884126c98a257259e0e4202859..c56dd54c7b8ab0420d6b2db9fc2e3784db54ce58 100644 (file)
--- a/drivers/serial/serial_pl01x_internal.h
+++ b/drivers/serial/serial_pl01x_internal.h
@@ -38,7 +38,20 @@ struct pl01x_regs {
        u32     pl011_lcrh;     /* 0x2C Line control register */
        u32     pl011_cr;       /* 0x30 Control register */
 };
-#endif
+
+#ifdef CONFIG_DM_SERIAL
+
+int pl01x_serial_ofdata_to_platdata(struct udevice *dev);
+int pl01x_serial_probe(struct udevice *dev);
+extern const struct dm_serial_ops pl01x_serial_ops;
+
+struct pl01x_priv {
+       struct pl01x_regs *regs;
+       enum pl01x_type type;
+};
+
+#endif /* CONFIG_DM_SERIAL */
+#endif /* !__ASSEMBLY__ */
 
 #define UART_PL01x_RSR_OE               0x08
 #define UART_PL01x_RSR_BE               0x04