openwrt/target/linux/bcm27xx/patches-5.15/950-0057-amba_pl011-Round-input-clock-up.patch
John Audia 4921ab0be4 kernel: bump 5.15 to 5.15.56
Manually rebased:
  bcm27xx/patches-5.15/950-0470-sound-usb-add-device-quirks-for-A4Tech-FHD-1080p-web.patch

Remove upstreamed:
  bcm27xx/patches-5.15/950-0060-tty-amba-pl011-Add-un-throttle-support.patch[1]

All other patches automatically rebased.

1. https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.15.56&id=2db3b95166f72e6481a79b82b1d6f94f4b18fcc1

Build system: x86_64
Build-tested: bcm2711/RPi4B, mt7622/RT3200
Run-tested: bcm2711/RPi4B, mt7622/RT3200

Signed-off-by: John Audia <therealgraysky@proton.me>
2022-07-31 18:55:22 +02:00

87 lines
2.5 KiB
Diff

From 307744a359bddf354711e54836e4757788c9dfc4 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
@@ -1727,6 +1727,23 @@ 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 =
@@ -1743,7 +1760,7 @@ 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 |
@@ -2440,7 +2457,7 @@ static int pl011_console_setup(struct co
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;
@@ -2657,6 +2674,7 @@ 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;
@@ -2688,6 +2706,7 @@ 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)