serial: pl01x: Add support for devices with the rate pre-configured.

For Raspberry Pi, we had the input clock rate to the pl011 fixed in the rpi.c file, but it may be changed by firmware due to user changes to config.txt. Since the firmware always sets up the uart (default 115200 output unless the user changes it), we can just skip our own uart init to simplify the boot process and more reliably get serial output. Signed-off-by: Eric Anholt <eric@anholt.net> Reviewed-by: Tom Rini <trini@konsulko.com> Tested-by: Stephen Warren <swarren@wwwdotorg.org>

serial: pl01x: Add support for devices with the rate pre-configured.
For Raspberry Pi, we had the input clock rate to the pl011 fixed in the rpi.c file, but it may be changed by firmware due to user changes to config.txt. Since the firmware always sets up the uart (default 115200 output unless the user changes it), we can just skip our own uart init to simplify the boot process and more reliably get serial output. Signed-off-by: Eric Anholt <eric@anholt.net> Reviewed-by: Tom Rini <trini@konsulko.com> Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Eric Anholt · Tom Rini
1 parent 9a6598daaf
Showing 3 changed files with 12 additions and 3 deletions Side-by-side Diff
board/raspberrypi/rpi/rpi.c
drivers/serial/serial_pl01x.c
include/dm/platform_data/serial_pl01x.h
@@ -37,7 +37,7 @@
 	.base = 0x20201000,
 #endif
 	.type = TYPE_PL011,
-	.clock = 3000000,
+	.skip_init = true,
 };
  
 U_BOOT_DEVICE(bcm2835_serials) = {
@@ -284,7 +284,10 @@
 	struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
 	struct pl01x_priv *priv = dev_get_priv(dev);
  
-	pl01x_generic_setbrg(priv->regs, priv->type, plat->clock, baudrate);
+	if (!plat->skip_init) {
+		pl01x_generic_setbrg(priv->regs, priv->type, plat->clock,
+				     baudrate);
+	}
  
 	return 0;
 }
@@ -296,7 +299,10 @@
  
 	priv->regs = (struct pl01x_regs *)plat->base;
 	priv->type = plat->type;
-	return pl01x_generic_serial_init(priv->regs, priv->type);
+	if (!plat->skip_init)
+		return pl01x_generic_serial_init(priv->regs, priv->type);
+	else
+		return 0;
 }
  
 static int pl01x_serial_getc(struct udevice *dev)
@@ -17,11 +17,14 @@
  * @base: Register base address
  * @type: Port type
  * @clock: Input clock rate, used for calculating the baud rate divisor
+ * @skip_init: Don't attempt to change port configuration (also means @clock
+ * is ignored)
  */
 struct pl01x_serial_platdata {
 	unsigned long base;
 	enum pl01x_type type;
 	unsigned int clock;
+	bool skip_init;
 };
  
 #endif
...	...	@@ -37,7 +37,7 @@
37	37	.base = 0x20201000,
38	38	#endif
39	39	.type = TYPE_PL011,
40		- .clock = 3000000,
	40	+ .skip_init = true,
41	41	};
42	42
43	43	U_BOOT_DEVICE(bcm2835_serials) = {
...	...	@@ -284,7 +284,10 @@
284	284	struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
285	285	struct pl01x_priv *priv = dev_get_priv(dev);
286	286
287		- pl01x_generic_setbrg(priv->regs, priv->type, plat->clock, baudrate);
	287	+ if (!plat->skip_init) {
	288	+ pl01x_generic_setbrg(priv->regs, priv->type, plat->clock,
	289	+ baudrate);
	290	+ }
288	291
289	292	return 0;
290	293	}
...	...	@@ -296,7 +299,10 @@
296	299
297	300	priv->regs = (struct pl01x_regs *)plat->base;
298	301	priv->type = plat->type;
299		- return pl01x_generic_serial_init(priv->regs, priv->type);
	302	+ if (!plat->skip_init)
	303	+ return pl01x_generic_serial_init(priv->regs, priv->type);
	304	+ else
	305	+ return 0;
300	306	}
301	307
302	308	static int pl01x_serial_getc(struct udevice *dev)
...	...	@@ -17,11 +17,14 @@
17	17	* @base: Register base address
18	18	* @type: Port type
19	19	* @clock: Input clock rate, used for calculating the baud rate divisor
	20	+ * @skip_init: Don't attempt to change port configuration (also means @clock
	21	+ * is ignored)
20	22	*/
21	23	struct pl01x_serial_platdata {
22	24	unsigned long base;
23	25	enum pl01x_type type;
24	26	unsigned int clock;
	27	+ bool skip_init;
25	28	};
26	29
27	30	#endif