openwrt/target/linux/bcm27xx/patches-4.19/950-0034-amba_pl011-Round-input-clock-up.patch
Adrian Schmutzler 7d7aa2fd92 brcm2708: rename target to bcm27xx
This change makes the names of Broadcom targets consistent by using
the common notation based on SoC/CPU ID (which is used internally
anyway), bcmXXXX instead of brcmXXXX.
This is even used for target TITLE in make menuconfig already,
only the short target name used brcm so far.

Despite, since subtargets range from bcm2708 to bcm2711, it seems
appropriate to use bcm27xx instead of bcm2708 (again, as already done
for BOARDNAME).

This also renames the packages brcm2708-userland and brcm2708-gpu-fw.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Acked-by: Álvaro Fernández Rojas <noltari@gmail.com>
2020-02-14 14:10:51 +01:00

87 lines
2.5 KiB
Diff

From 610cb34f3d7c5fdffb0db82538731714a2df1d13 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Wed, 1 Mar 2017 16:07:39 +0000
Subject: [PATCH] amba_pl011: Round input clock up
The UART clock is initialised to be as close to the requested
frequency as possible without exceeding it. Now that there is a
clock manager that returns the actual frequencies, an expected
48MHz clock is reported as 47999625. If the requested baudrate
== requested clock/16, there is no headroom and the slight
reduction in actual clock rate results in failure.
Detect cases where it looks like a "round" clock was chosen and
adjust the reported clock to match that "round" value. As the
code comment says:
/*
* If increasing a clock by less than 0.1% changes it
* from ..999.. to ..000.., round up.
*/
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
---
drivers/tty/serial/amba-pl011.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1650,6 +1650,23 @@ static void pl011_put_poll_char(struct u
#endif /* CONFIG_CONSOLE_POLL */
+unsigned long pl011_clk_round(unsigned long clk)
+{
+ unsigned long scaler;
+
+ /*
+ * If increasing a clock by less than 0.1% changes it
+ * from ..999.. to ..000.., round up.
+ */
+ scaler = 1;
+ while (scaler * 100000 < clk)
+ scaler *= 10;
+ if ((clk + scaler - 1)/scaler % 1000 == 0)
+ clk = (clk/scaler + 1) * scaler;
+
+ return clk;
+}
+
static int pl011_hwinit(struct uart_port *port)
{
struct uart_amba_port *uap =
@@ -1666,7 +1683,7 @@ static int pl011_hwinit(struct uart_port
if (retval)
return retval;
- uap->port.uartclk = clk_get_rate(uap->clk);
+ uap->port.uartclk = pl011_clk_round(clk_get_rate(uap->clk));
/* Clear pending error and receive interrupts */
pl011_write(UART011_OEIS | UART011_BEIS | UART011_PEIS |
@@ -2322,7 +2339,7 @@ static int __init pl011_console_setup(st
plat->init();
}
- uap->port.uartclk = clk_get_rate(uap->clk);
+ uap->port.uartclk = pl011_clk_round(clk_get_rate(uap->clk));
if (uap->vendor->fixed_options) {
baud = uap->fixed_baud;
@@ -2507,6 +2524,7 @@ static struct uart_driver amba_reg = {
.cons = AMBA_CONSOLE,
};
+#if 0
static int pl011_probe_dt_alias(int index, struct device *dev)
{
struct device_node *np;
@@ -2538,6 +2556,7 @@ static int pl011_probe_dt_alias(int inde
return ret;
}
+#endif
/* unregisters the driver also if no more ports are left */
static void pl011_unregister_port(struct uart_amba_port *uap)