bcm2835_pl011_serial: Add BCM2835 specific serial driver
authorAlexander Graf <agraf@suse.de>
Thu, 25 Jan 2018 11:05:55 +0000 (12:05 +0100)
committerTom Rini <trini@konsulko.com>
Sun, 28 Jan 2018 17:27:36 +0000 (12:27 -0500)
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>
MAINTAINERS
drivers/serial/Kconfig
drivers/serial/Makefile
drivers/serial/serial_bcm283x_pl011.c [new file with mode: 0644]
drivers/serial/serial_pl01x.c
drivers/serial/serial_pl01x_internal.h

index dd24697f15acbacccd5b1137f474e5905b251ffe..0c7efde5a5b5cafb6c9866b786ad3899f8cb5963 100644 (file)
@@ -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/
index 72281a7b64ea6b56676a550b6cd1b5e82d211a5d..3ffedba525657ea587882562daa9c2b81dca8217 100644 (file)
@@ -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
index 5ef603ab1521c27f1261624762d9acc2ca47ff9a..cac9a8b31212f4a4fe34cdd732f6ea74a140bb39 100644 (file)
@@ -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
@@ -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),
+};
index 2cbc84c1b46aa50eec0f5a949fca182fe3a1e105..23d9d839cbc1c249af6e0556ff11dbb8e03d4740 100644 (file)
@@ -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;
index 288a4f19f56c2e884126c98a257259e0e4202859..c56dd54c7b8ab0420d6b2db9fc2e3784db54ce58 100644 (file)
@@ -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