[PATCH v2 06/32] serial: msm: add debug UART

[Caleb Connolly]

On 18/01/2024 21:54, Ramon Fried wrote:
> On Tue, Dec 19, 2023 at 6:04 PM Caleb Connolly
> <caleb.connolly at linaro.org> wrote:
>>
>> Introduce support for early debugging.
>>
>> Signed-off-by: Caleb Connolly <caleb.connolly at linaro.org>
>> ---
>>  drivers/serial/Kconfig      |  8 ++++++++
>>  drivers/serial/serial_msm.c | 32 ++++++++++++++++++++++++++++++++
>>  2 files changed, 40 insertions(+)
>>
>> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
>> index 81fdac047824..20713812c839 100644
>> --- a/drivers/serial/Kconfig
>> +++ b/drivers/serial/Kconfig
>> @@ -304,6 +304,14 @@ config DEBUG_UART_S5P
>>           will need to provide parameters to make this work. The driver will
>>           be available until the real driver-model serial is running.
>>
>> +config DEBUG_UART_MSM
>> +       bool "Qualcomm QUP UART debug"
> What is QUP ?

It's "Qualcomm Universal Peripheral".
>> +       depends on ARCH_SNAPDRAGON
>> +       help
>> +         Select this to enable a debug UART using the serial_msm driver. You
>> +         will need to provide parameters to make this work. The driver will
>> +         be available until the real driver-model serial is running.
>> +
>>  config DEBUG_UART_MSM_GENI
>>         bool "Qualcomm snapdragon"
>>         depends on ARCH_SNAPDRAGON
>> diff --git a/drivers/serial/serial_msm.c b/drivers/serial/serial_msm.c
>> index a22623c316ed..19a5a3a788f7 100644
>> --- a/drivers/serial/serial_msm.c
>> +++ b/drivers/serial/serial_msm.c
>> @@ -253,3 +253,35 @@ U_BOOT_DRIVER(serial_msm) = {
>>         .probe = msm_serial_probe,
>>         .ops    = &msm_serial_ops,
>>  };
>> +
>> +#ifdef CONFIG_DEBUG_UART_MSM
>> +
>> +static struct msm_serial_data init_serial_data = {
>> +       .base = CONFIG_VAL(DEBUG_UART_BASE),
>> +       .clk_bit_rate = UART_DM_CLK_RX_TX_BIT_RATE,
>> +};
>> +
>> +#include <debug_uart.h>
>> +
>> +static inline void _debug_uart_init(void)
>> +{
>> +       uart_dm_init(&init_serial_data);
>> +}
>> +
>> +static inline void _debug_uart_putc(int ch)
>> +{
>> +       struct msm_serial_data *priv = &init_serial_data;
>> +
>> +       while (!(readl(priv->base + UARTDM_SR) & UARTDM_SR_TX_EMPTY) &&
>> +              !(readl(priv->base + UARTDM_ISR) & UARTDM_ISR_TX_READY))
>> +               ;
>> +
>> +       writel(UARTDM_CR_CMD_RESET_TX_READY, priv->base + UARTDM_CR);
>> +
>> +       writel(1, priv->base + UARTDM_NCF_TX);
>> +       writel(ch, priv->base + UARTDM_TF);
>> +}
>> +
>> +DEBUG_UART_FUNCS
>> +
>> +#endif
>>
>> --
>> 2.42.1
>>

-- 
// Caleb (they/them)