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>

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>
Alexander Graf · Tom Rini
1 parent 958d55f26c
Showing 6 changed files with 101 additions and 9 deletions Side-by-side Diff
MAINTAINERS
drivers/serial/Kconfig
drivers/serial/Makefile
drivers/serial/serial_bcm283x_pl011.c
drivers/serial/serial_pl01x.c
drivers/serial/serial_pl01x_internal.h
@@ -99,6 +99,7 @@
 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/
@@ -395,6 +395,15 @@
 	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
@@ -46,6 +46,7 @@
 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
+/*
+ * 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),
+};
@@ -273,11 +273,6 @@
  
 #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 @@
 	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 @@
 		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 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;
@@ -38,7 +38,20 @@
 	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
...	...	@@ -99,6 +99,7 @@
99	99	F: drivers/mmc/bcm2835_sdhci.c
100	100	F: drivers/mmc/bcm2835_sdhost.c
101	101	F: drivers/serial/serial_bcm283x_mu.c
	102	+F: drivers/serial/serial_bcm283x_pl011.c
102	103	F: drivers/video/bcm2835.c
103	104	F: include/dm/platform_data/serial_bcm283x_mu.h
104	105	F: drivers/pinctrl/broadcom/
...	...	@@ -395,6 +395,15 @@
395	395	help
396	396	Select this to enable Mini-UART support on BCM283X family of SoCs.
397	397
	398	+config BCM283X_PL011_SERIAL
	399	+ bool "Support for BCM283x PL011 UART"
	400	+ depends on PL01X_SERIAL && ARCH_BCM283X
	401	+ default y
	402	+ help
	403	+ Select this to enable an overriding PL011 driver for BCM283X SoCs
	404	+ that supports automatic disable, so that it only gets used when
	405	+ the UART is actually muxed.
	406	+
398	407	config BCM6345_SERIAL
399	408	bool "Support for BCM6345 UART"
400	409	depends on DM_SERIAL && ARCH_BMIPS
...	...	@@ -46,6 +46,7 @@
46	46	obj-$(CONFIG_PIC32_SERIAL) += serial_pic32.o
47	47	obj-$(CONFIG_STM32_SERIAL) += serial_stm32.o
48	48	obj-$(CONFIG_BCM283X_MU_SERIAL) += serial_bcm283x_mu.o
	49	+obj-$(CONFIG_BCM283X_PL011_SERIAL) += serial_bcm283x_pl011.o
49	50	obj-$(CONFIG_MSM_SERIAL) += serial_msm.o
50	51	obj-$(CONFIG_MVEBU_A3700_UART) += serial_mvebu_a3700.o
51	52	obj-$(CONFIG_MPC8XX_CONS) += serial_mpc8xx.o
	1	+/*
	2	+ * Copyright (c) 2018 Alexander Graf <agraf@suse.de>
	3	+ *
	4	+ * SPDX-License-Identifier: GPL-2.0+
	5	+ */
	6	+
	7	+#include <common.h>
	8	+#include <dm.h>
	9	+#include <asm/gpio.h>
	10	+#include <dm/pinctrl.h>
	11	+#include <dm/platform_data/serial_pl01x.h>
	12	+#include "serial_pl01x_internal.h"
	13	+
	14	+/*
	15	+ * Check if this serial device is muxed
	16	+ *
	17	+ * The serial device will only work properly if it has been muxed to the serial
	18	+ * pins by firmware. Check whether that happened here.
	19	+ *
	20	+ * @return true if serial device is muxed, false if not
	21	+ */
	22	+static bool bcm283x_is_serial_muxed(void)
	23	+{
	24	+ int serial_gpio = 15;
	25	+ struct udevice *dev;
	26	+
	27	+ if (uclass_first_device(UCLASS_PINCTRL, &dev) \|\| !dev)
	28	+ return false;
	29	+
	30	+ if (pinctrl_get_gpio_mux(dev, 0, serial_gpio) != BCM2835_GPIO_ALT0)
	31	+ return false;
	32	+
	33	+ return true;
	34	+}
	35	+
	36	+static int bcm283x_pl011_serial_ofdata_to_platdata(struct udevice *dev)
	37	+{
	38	+ struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
	39	+ int ret;
	40	+
	41	+ /* Don't spawn the device if it's not muxed */
	42	+ if (!bcm283x_is_serial_muxed())
	43	+ return -ENODEV;
	44	+
	45	+ ret = pl01x_serial_ofdata_to_platdata(dev);
	46	+ if (ret)
	47	+ return ret;
	48	+
	49	+ /*
	50	+ * TODO: Reinitialization doesn't always work for now, just skip
	51	+ * init always - we know we're already initialized
	52	+ */
	53	+ plat->skip_init = true;
	54	+
	55	+ return 0;
	56	+}
	57	+
	58	+static const struct udevice_id bcm283x_pl011_serial_id[] = {
	59	+ {.compatible = "brcm,bcm2835-pl011", .data = TYPE_PL011},
	60	+ {}
	61	+};
	62	+
	63	+U_BOOT_DRIVER(bcm283x_pl011_uart) = {
	64	+ .name = "bcm283x_pl011",
	65	+ .id = UCLASS_SERIAL,
	66	+ .of_match = of_match_ptr(bcm283x_pl011_serial_id),
	67	+ .ofdata_to_platdata = of_match_ptr(bcm283x_pl011_serial_ofdata_to_platdata),
	68	+ .platdata_auto_alloc_size = sizeof(struct pl01x_serial_platdata),
	69	+ .probe = pl01x_serial_probe,
	70	+ .ops = &pl01x_serial_ops,
	71	+ .flags = DM_FLAG_PRE_RELOC,
	72	+ .priv_auto_alloc_size = sizeof(struct pl01x_priv),
	73	+};
...	...	@@ -273,11 +273,6 @@
273	273
274	274	#ifdef CONFIG_DM_SERIAL
275	275
276		-struct pl01x_priv {
277		- struct pl01x_regs *regs;
278		- enum pl01x_type type;
279		-};
280		-
281	276	static int pl01x_serial_setbrg(struct udevice *dev, int baudrate)
282	277	{
283	278	struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
...	...	@@ -291,7 +286,7 @@
291	286	return 0;
292	287	}
293	288
294		-static int pl01x_serial_probe(struct udevice *dev)
	289	+int pl01x_serial_probe(struct udevice *dev)
295	290	{
296	291	struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
297	292	struct pl01x_priv *priv = dev_get_priv(dev);
...	...	@@ -329,7 +324,7 @@
329	324	return fr & UART_PL01x_FR_TXFF ? 0 : 1;
330	325	}
331	326
332		-static const struct dm_serial_ops pl01x_serial_ops = {
	327	+const struct dm_serial_ops pl01x_serial_ops = {
333	328	.putc = pl01x_serial_putc,
334	329	.pending = pl01x_serial_pending,
335	330	.getc = pl01x_serial_getc,
...	...	@@ -343,7 +338,7 @@
343	338	{}
344	339	};
345	340
346		-static int pl01x_serial_ofdata_to_platdata(struct udevice *dev)
	341	+int pl01x_serial_ofdata_to_platdata(struct udevice *dev)
347	342	{
348	343	struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
349	344	fdt_addr_t addr;
...	...	@@ -38,7 +38,20 @@
38	38	u32 pl011_lcrh; /* 0x2C Line control register */
39	39	u32 pl011_cr; /* 0x30 Control register */
40	40	};
41		-#endif
	41	+
	42	+#ifdef CONFIG_DM_SERIAL
	43	+
	44	+int pl01x_serial_ofdata_to_platdata(struct udevice *dev);
	45	+int pl01x_serial_probe(struct udevice *dev);
	46	+extern const struct dm_serial_ops pl01x_serial_ops;
	47	+
	48	+struct pl01x_priv {
	49	+ struct pl01x_regs *regs;
	50	+ enum pl01x_type type;
	51	+};
	52	+
	53	+#endif /* CONFIG_DM_SERIAL */
	54	+#endif /* !__ASSEMBLY__ */
42	55
43	56	#define UART_PL01x_RSR_OE 0x08
44	57	#define UART_PL01x_RSR_BE 0x04