openwrt/target/linux/bcm27xx/patches-5.15/950-0057-amba_pl011-Round-input-clock-up.patch
John Audia 67d998e25d
kernel: bump 5.15 to 5.15.145
Changelog: https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.145

No patches needed a rebase.

 23.05 backport:

    Rebased patch mediatek/100-dts-update-mt7622-rfb1.patch due to
    changes introduced in commit e37aa926447f ("arm64: dts: mediatek:
    mt7622: fix memory node warning check") in version v5.15.143 and we
    jumped over from v5.15.139 directly to v5.15.145.

Build system: x86_64
Build-tested: ramips/tplink_archer-a6-v3
Run-tested: ramips/tplink_archer-a6-v3

 23.05 backport:

  Stijn:
   Compile-tested: ath79/generic, ipq40xx/generic, mvebu/cortexa72, ramips/mt{7621,7620,76x8}, realtek/rtl{838x,930x}, 86/64.
   Run-tested: cortexa72 (RB5009UG+S+IN), mt7621 (EAP615-Wall v1), rtl838x (GS1900-10HP, GS1900-8HP, GS108T v3).

  Petr:
   Compile-tested: ipq807x, mvebu/cortexa9
   Run-tested: turris-omnia, prpl-haze

Tested-by: Stijn Segers <foss@volatilesystems.org> [23.05 testing]
Signed-off-by: John Audia <therealgraysky@proton.me>
Signed-off-by: Petr Štetiar <ynezz@true.cz> [23.05 refresh]
(cherry picked from commit 8de4cc77a6)
2024-01-07 12:57:30 +00:00

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
@@ -1726,6 +1726,23 @@ 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 =
@@ -1742,7 +1759,7 @@ 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 |
@@ -2448,7 +2465,7 @@ 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;
@@ -2665,6 +2682,7 @@ 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;
@@ -2696,6 +2714,7 @@ 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)