Merge branch 'master' of https://gitlab.denx.de/u-boot/custodians/u-boot-spi

[oweals/u-boot.git] / drivers / serial / serial_bcm283x_mu.c

diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c
index e7ed8993b847009795c1cb32788f826ff8e34b23..a6ffc84b963e8468d2691bd5927132f50f68d2b3 100644 (file)
--- a/drivers/serial/serial_bcm283x_mu.c
+++ b/drivers/serial/serial_bcm283x_mu.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2016 Stephen Warren <swarren@wwwdotorg.org>
  *
@@ -9,8 +10,6 @@
  * (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 */
@@ -19,13 +18,12 @@
 #include <dm.h>
 #include <errno.h>
 #include <watchdog.h>
+#include <asm/gpio.h>
 #include <asm/io.h>
 #include <serial.h>
 #include <dm/platform_data/serial_bcm283x_mu.h>
+#include <dm/pinctrl.h>
 #include <linux/compiler.h>
-#include <fdtdec.h>
-
-DECLARE_GLOBAL_DATA_PTR;
 
 struct bcm283x_mu_regs {
        u32 io;
@@ -52,6 +50,8 @@ struct bcm283x_mu_priv {
        struct bcm283x_mu_regs *regs;
 };
 
+static int bcm283x_mu_serial_getc(struct udevice *dev);
+
 static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate)
 {
        struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
@@ -59,14 +59,18 @@ static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate)
        struct bcm283x_mu_regs *regs = priv->regs;
        u32 divider;
 
-       if (plat->disabled || plat->skip_init)
-               return 0;
+       if (plat->skip_init)
+               goto out;
 
        divider = plat->clock / (baudrate * 8);
 
        writel(BCM283X_MU_LCR_DATA_SIZE_8, &regs->lcr);
        writel(divider - 1, &regs->baud);
 
+out:
+       /* Flush the RX queue - all data in there is bogus */
+       while (bcm283x_mu_serial_getc(dev) != -EAGAIN) ;
+
        return 0;
 }
 
@@ -75,9 +79,6 @@ 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);
 
-       if (plat->disabled)
-               return -ENODEV;
-
        priv->regs = (struct bcm283x_mu_regs *)plat->base;
 
        return 0;
@@ -85,14 +86,10 @@ static int bcm283x_mu_serial_probe(struct udevice *dev)
 
 static int bcm283x_mu_serial_getc(struct udevice *dev)
 {
-       struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
        struct bcm283x_mu_priv *priv = dev_get_priv(dev);
        struct bcm283x_mu_regs *regs = priv->regs;
        u32 data;
 
-       if (plat->disabled)
-               return -EAGAIN;
-
        /* Wait until there is data in the FIFO */
        if (!(readl(&regs->lsr) & BCM283X_MU_LSR_RX_READY))
                return -EAGAIN;
@@ -104,13 +101,9 @@ static int bcm283x_mu_serial_getc(struct udevice *dev)
 
 static int bcm283x_mu_serial_putc(struct udevice *dev, const char data)
 {
-       struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
        struct bcm283x_mu_priv *priv = dev_get_priv(dev);
        struct bcm283x_mu_regs *regs = priv->regs;
 
-       if (plat->disabled)
-               return 0;
-
        /* Wait until there is space in the FIFO */
        if (!(readl(&regs->lsr) & BCM283X_MU_LSR_TX_EMPTY))
                return -EAGAIN;
@@ -123,14 +116,10 @@ static int bcm283x_mu_serial_putc(struct udevice *dev, const char data)
 
 static int bcm283x_mu_serial_pending(struct udevice *dev, bool input)
 {
-       struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
        struct bcm283x_mu_priv *priv = dev_get_priv(dev);
        struct bcm283x_mu_regs *regs = priv->regs;
        unsigned int lsr;
 
-       if (plat->disabled)
-               return 0;
-
        lsr = readl(&regs->lsr);
 
        if (input) {
@@ -154,21 +143,50 @@ static const struct udevice_id bcm283x_mu_serial_id[] = {
        {}
 };
 
+/*
+ * 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_ALT5)
+               return false;
+
+       return true;
+}
+
 static int bcm283x_mu_serial_ofdata_to_platdata(struct udevice *dev)
 {
        struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
        fdt_addr_t addr;
 
-       addr = dev_get_addr(dev);
+       /* Don't spawn the device if it's not muxed */
+       if (!bcm283x_is_serial_muxed())
+               return -ENODEV;
+
+       addr = devfdt_get_addr(dev);
        if (addr == FDT_ADDR_T_NONE)
                return -EINVAL;
 
        plat->base = addr;
-       plat->clock = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev), "clock",
-                                    1);
-       plat->skip_init = fdtdec_get_bool(gd->fdt_blob, dev_of_offset(dev),
-                                         "skip-init");
-       plat->disabled = false;
+       plat->clock = dev_read_u32_default(dev, "clock", 1);
+
+       /*
+        * TODO: Reinitialization doesn't always work for now, just skip
+        *       init always - we know we're already initialized
+        */
+       plat->skip_init = true;
+
        return 0;
 }
 #endif
@@ -181,6 +199,8 @@ U_BOOT_DRIVER(serial_bcm283x_mu) = {
        .platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata),
        .probe = bcm283x_mu_serial_probe,
        .ops = &bcm283x_mu_serial_ops,
+#if !CONFIG_IS_ENABLED(OF_CONTROL) || CONFIG_IS_ENABLED(OF_BOARD)
        .flags = DM_FLAG_PRE_RELOC,
+#endif
        .priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv),
 };