diff options
| author | Naresh Solanki <Naresh.Solanki@9elements.com> | 2023-08-10 13:21:44 +0200 |
|---|---|---|
| committer | Lean Sheng Tan <sheng.tan@9elements.com> | 2023-12-13 14:27:09 +0000 |
| commit | 54662610197d7304b48d8e85a5b13263db3357f2 (patch) | |
| tree | 757cc0560b30e2099ee6c3892bfdf731eca5e3e1 /src/drivers/uart/pl011.c | |
| parent | 3e25f85d68d10249473d422c4c19dc30ea55e8b0 (diff) | |
drivers/uart/pl011.c Perform basic UART init
Configure UART baud rate, Line Control register as 8n1 with FIFO
enable and enable UART TX and RX.
Change-Id: I090344a20430dc370a0b93ff7fbbae54111fae24
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79406
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Diffstat (limited to 'src/drivers/uart/pl011.c')
| -rw-r--r-- | src/drivers/uart/pl011.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/src/drivers/uart/pl011.c b/src/drivers/uart/pl011.c index 64c279d1b4..06782a3b98 100644 --- a/src/drivers/uart/pl011.c +++ b/src/drivers/uart/pl011.c @@ -7,6 +7,38 @@ void uart_init(unsigned int idx) { + struct pl011_uart *regs = uart_platform_baseptr(idx); + uint32_t tmp; + + if (!regs) + return; + + /* Disable UART */ + tmp = read32(®s->cr); + tmp &= ~PL011_UARTCR_UARTEN; + write32(®s->cr, tmp); + + /* + * Program Divisor + * As per: PL011 Technical reference manual: + * BAUDDIV = (Fuartclk / (16 * baud_rate)) + * Considering 6 bits(64) for UARTFBRD + * BAUDDIV = (Fuartclk * 4 / baud_rate) + */ + tmp = uart_platform_refclk() * 4 / get_uart_baudrate(); + + write32(®s->ibrd, tmp >> 6); + write32(®s->fbrd, tmp & 0x3f); + + /* Program LINE Control 8n1, FIFO enable */ + tmp = read32(®s->lcr_h); + tmp |= PL011_LINE_CONTROL; + write32(®s->lcr_h, tmp); + + /* Enable UART */ + tmp = read32(®s->cr); + tmp |= PL011_UARTCR_UARTEN | PL011_UARTCR_RXE | PL011_UARTCR_TXE; + write32(®s->cr, tmp); } void uart_tx_byte(unsigned int idx, unsigned char data) |