diff options
Diffstat (limited to 'package/boot/arm-trusted-firmware-mvebu/patches/100-fix-plat-marvell-a3720-uart-fix-UART-clock-rate-valu.patch')
| -rw-r--r-- | package/boot/arm-trusted-firmware-mvebu/patches/100-fix-plat-marvell-a3720-uart-fix-UART-clock-rate-valu.patch | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/package/boot/arm-trusted-firmware-mvebu/patches/100-fix-plat-marvell-a3720-uart-fix-UART-clock-rate-valu.patch b/package/boot/arm-trusted-firmware-mvebu/patches/100-fix-plat-marvell-a3720-uart-fix-UART-clock-rate-valu.patch new file mode 100644 index 0000000000..6f887411b4 --- /dev/null +++ b/package/boot/arm-trusted-firmware-mvebu/patches/100-fix-plat-marvell-a3720-uart-fix-UART-clock-rate-valu.patch @@ -0,0 +1,60 @@ +From 66a7752834382595d26214783ae4698fd1f00bd6 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org> +Date: Thu, 13 May 2021 14:53:44 +0200 +Subject: [PATCH] fix(plat/marvell/a3720/uart): fix UART clock rate value and + divisor calculation +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +UART parent clock is by default the platform's xtal clock, which is +25 MHz. + +The value defined in the driver, though, is 25.8048 MHz. This is a hack +for the suboptimal divisor calculation + Divisor = UART clock / (16 * baudrate) +which does not use rounding division, resulting in a suboptimal value +for divisor if the correct parent clock rate was used. + +Change the code for divisor calculation to + Divisor = Round(UART clock / (16 * baudrate)) +and change the parent clock rate value to 25 MHz. + +The final UART divisor for default baudrate 115200 is not affected by +this change. + +(Note that the parent clock rate should not be defined via a macro, +since the xtal clock can also be 40 MHz. This is outside of the scope of +this fix, though.) + +Signed-off-by: Pali Rohár <pali@kernel.org> +Change-Id: Iaa401173df87aec94f2dd1b38a90fb6ed0bf0ec6 +--- + drivers/marvell/uart/a3700_console.S | 3 ++- + plat/marvell/armada/a3k/common/include/platform_def.h | 2 +- + 2 files changed, 3 insertions(+), 2 deletions(-) + +--- a/drivers/marvell/uart/a3700_console.S ++++ b/drivers/marvell/uart/a3700_console.S +@@ -45,8 +45,9 @@ func console_a3700_core_init + cbz w2, init_fail + + /* Program the baudrate */ +- /* Divisor = Uart clock / (16 * baudrate) */ ++ /* Divisor = Round(Uartclock / (16 * baudrate)) */ + lsl w2, w2, #4 ++ add w1, w1, w2, lsr #1 + udiv w2, w1, w2 + and w2, w2, #0x3ff + +--- a/plat/marvell/armada/a3k/common/include/platform_def.h ++++ b/plat/marvell/armada/a3k/common/include/platform_def.h +@@ -164,7 +164,7 @@ + * PL011 related constants + */ + #define PLAT_MARVELL_BOOT_UART_BASE (MVEBU_REGS_BASE + 0x12000) +-#define PLAT_MARVELL_BOOT_UART_CLK_IN_HZ 25804800 ++#define PLAT_MARVELL_BOOT_UART_CLK_IN_HZ 25000000 + + #define PLAT_MARVELL_CRASH_UART_BASE PLAT_MARVELL_BOOT_UART_BASE + #define PLAT_MARVELL_CRASH_UART_CLK_IN_HZ PLAT_MARVELL_BOOT_UART_CLK_IN_HZ |