[PATCH] lib: utils: serial: Add Cadence UART driver
Anup Patel
anup at brainfault.org
Fri Jul 8 05:10:17 PDT 2022
On Fri, Jul 8, 2022 at 11:21 AM Jun Liang Tan
<junliang.tan at linux.starfivetech.com> wrote:
>
> Add Cadence UART driver
>
> Signed-off-by: Jun Liang Tan <junliang.tan at linux.starfivetech.com>
> Signed-off-by: Wei Liang Lim <weiliang.lim at linux.starfivetech.com>
> ---
> include/sbi_utils/fdt/fdt_helper.h | 3 +
> include/sbi_utils/serial/cadence-uart.h | 16 +++
> lib/utils/fdt/fdt_helper.c | 35 +++++++
> lib/utils/serial/cadence-uart.c | 125 ++++++++++++++++++++++++
> lib/utils/serial/fdt_serial.c | 2 +
> lib/utils/serial/fdt_serial_cadence.c | 35 +++++++
> lib/utils/serial/objects.mk | 2 +
> 7 files changed, 218 insertions(+)
> create mode 100644 include/sbi_utils/serial/cadence-uart.h
> create mode 100644 lib/utils/serial/cadence-uart.c
> create mode 100644 lib/utils/serial/fdt_serial_cadence.c
>
> diff --git a/include/sbi_utils/fdt/fdt_helper.h b/include/sbi_utils/fdt/fdt_helper.h
> index 24fee7a..1166208 100644
> --- a/include/sbi_utils/fdt/fdt_helper.h
> +++ b/include/sbi_utils/fdt/fdt_helper.h
> @@ -53,6 +53,9 @@ int fdt_parse_max_hart_id(void *fdt, u32 *max_hartid);
>
> int fdt_parse_timebase_frequency(void *fdt, unsigned long *freq);
>
> +int fdt_parse_cadence_uart_node(void *fdt, int nodeoffset,
> + struct platform_uart_data *uart);
> +
> int fdt_parse_gaisler_uart_node(void *fdt, int nodeoffset,
> struct platform_uart_data *uart);
>
> diff --git a/include/sbi_utils/serial/cadence-uart.h b/include/sbi_utils/serial/cadence-uart.h
> new file mode 100644
> index 0000000..e75fb95
> --- /dev/null
> +++ b/include/sbi_utils/serial/cadence-uart.h
> @@ -0,0 +1,16 @@
> +/*
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2022 StarFive Technology Co., Ltd.
> + *
> + * Author: Jun Liang Tan <junliang.tan at linux.starfivetech.com>
> + */
> +
> +#ifndef __SERIAL_CADENCE_UART_H__
> +#define __SERIAL_CADENCE_UART_H__
> +
> +#include <sbi/sbi_types.h>
> +
> +int cadence_uart_init(unsigned long base, u32 in_freq, u32 baudrate);
> +
> +#endif
> diff --git a/lib/utils/fdt/fdt_helper.c b/lib/utils/fdt/fdt_helper.c
> index 5bf4021..3ad0a5e 100644
> --- a/lib/utils/fdt/fdt_helper.c
> +++ b/lib/utils/fdt/fdt_helper.c
> @@ -290,6 +290,41 @@ int fdt_parse_timebase_frequency(void *fdt, unsigned long *freq)
> return 0;
> }
>
> +int fdt_parse_cadence_uart_node(void *fdt, int nodeoffset,
> + struct platform_uart_data *uart)
> +{
> + int len, rc;
> + const fdt32_t *val;
> + u64 reg_addr, reg_size;
> +
> + if (nodeoffset < 0 || !uart || !fdt)
> + return SBI_ENODEV;
> +
> + rc = fdt_get_node_addr_size(fdt, nodeoffset, 0,
> + ®_addr, ®_size);
> + if (rc < 0 || !reg_addr || !reg_size)
> + return SBI_ENODEV;
> + uart->addr = reg_addr;
> +
> + /**
> + * UART address is mandatory. clock-frequency and current-speed
> + * may not be present. Don't return error.
> + */
> + val = (fdt32_t *)fdt_getprop(fdt, nodeoffset, "clock-frequency", &len);
> + if (len > 0 && val)
> + uart->freq = fdt32_to_cpu(*val);
> + else
> + uart->freq = DEFAULT_UART_FREQ;
> +
> + val = (fdt32_t *)fdt_getprop(fdt, nodeoffset, "current-speed", &len);
> + if (len > 0 && val)
> + uart->baud = fdt32_to_cpu(*val);
> + else
> + uart->baud = DEFAULT_UART_BAUD;
> +
> + return 0;
> +}
> +
Instead of adding one more UART node parsing function better
rename fdt_parse_uart8250() to fdt_parse_uart() and use it in
place of fdt_parse_cadence_uart_node().
> int fdt_parse_gaisler_uart_node(void *fdt, int nodeoffset,
> struct platform_uart_data *uart)
> {
> diff --git a/lib/utils/serial/cadence-uart.c b/lib/utils/serial/cadence-uart.c
> new file mode 100644
> index 0000000..ffa79f8
> --- /dev/null
> +++ b/lib/utils/serial/cadence-uart.c
> @@ -0,0 +1,125 @@
> +/*
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2022 StarFive Technology Co., Ltd.
> + *
> + * Author: Jun Liang Tan <junliang.tan at linux.starfivetech.com>
> + */
> +
> +#include <sbi/riscv_io.h>
> +#include <sbi/sbi_console.h>
> +#include <sbi_utils/serial/cadence-uart.h>
> +
> +/* clang-format off */
> +
> +#define UART_REG_OFFSET_CTRL 0x00 /* Control register */
> +#define UART_REG_OFFSET_MODE 0x04 /* Mode register */
> +#define UART_REG_OFFSET_CH_STS 0x2C /* Channel status register */
> +#define UART_REG_OFFSET_RX_TX_FIFO 0x30 /* RX and TX FIFO register */
> +#define UART_REG_OFFSET_INT_DIS 0x0C /* Interrupt disable register */
> +#define UART_REG_OFFSET_BRG 0x18 /* Baud rate generator register */
> +#define UART_REG_OFFSET_BRD 0x34 /* Baud rate divider register */
> +
> +/* Control register, 0x00 */
> +#define UART_CR_TX_DIS 0x00000020 /* TX disabled, bit 5 */
> +#define UART_CR_TX_EN 0x00000010 /* TX enabled, bit 4 */
> +#define UART_CR_RX_DIS 0x00000008 /* RX disabled, bit 3 */
> +#define UART_CR_RX_EN 0x00000004 /* RX enabled, bit 2*/
> +#define UART_CR_TXRST 0x00000002 /* TX logic reset, bit 1 */
> +#define UART_CR_RXRST 0x00000001 /* RX logic reset, bit 0 */
> +
> +/* Channel status register, 0x2C */
> +#define UART_CHSR_TXFULL 0x00000010 /* TX FIFO full, bit 4 */
> +#define UART_CHSR_RXEMPTY 0x00000002 /* RX FIFO empty, bit 1 */
> +
> +/* Mode register, 0x04 */
> +#define UART_MR_PARITY_NONE 0x00000020 /* No parity set */
> +
> +/* Baud rate generator register, 0x18 */
> +#define UART_BRG_CLK_DIVISOR 0x00000001 /* baud_sample = sel_clk */
> +
> +/* clang-format on */
> +
> +static volatile void *uart_base;
> +static u32 uart_in_freq;
> +static u32 uart_baudrate;
> +
> +/**
> + * Find minimum divisor divides in_freq to max_target_hz;
> + * Based on SiFive UART driver (sifive-uart.c)
> + */
> +static inline unsigned int uart_min_clk_divisor(uint64_t in_freq,
> + uint64_t max_target_hz)
> +{
> + uint64_t quotient = (in_freq + max_target_hz - 1) / (max_target_hz);
> + /* Avoid underflow */
> + if (quotient == 0)
> + return 0;
> + else
> + return quotient - 1;
> +}
> +
> +static u32 get_reg(u32 offset)
> +{
> + return readl(uart_base + offset);
> +}
> +
> +static void set_reg(u32 offset, u32 val)
> +{
> + writel(val, uart_base + offset);
> +}
> +
> +static void cadence_uart_putc(char ch)
> +{
> + while (get_reg(UART_REG_OFFSET_CH_STS) & UART_CHSR_TXFULL)
> + ;
> +
> + set_reg(UART_REG_OFFSET_RX_TX_FIFO, ch);
> +}
> +
> +static int cadence_uart_getc(void)
> +{
> + u32 ret = get_reg(UART_REG_OFFSET_CH_STS);
> +
> + if (!(ret & UART_CHSR_RXEMPTY))
> + return get_reg(UART_REG_OFFSET_RX_TX_FIFO);
> + return -1;
> +}
> +
> +static struct sbi_console_device cadence_console = {
> + .name = "cadence_uart",
> + .console_putc = cadence_uart_putc,
> + .console_getc = cadence_uart_getc
> +};
> +
> +int cadence_uart_init(unsigned long base, u32 in_freq, u32 baudrate)
> +{
> + uart_base = (volatile void *)base;
> + uart_in_freq = in_freq;
> + uart_baudrate = baudrate;
> +
> + /* Disable interrupts */
> + set_reg(UART_REG_OFFSET_INT_DIS, 0xFFFFFFFF);
> + /* Disable TX RX */
> + set_reg(UART_REG_OFFSET_CTRL, UART_CR_TX_DIS | UART_CR_RX_DIS);
> + /* Configure baudrate */
> + if (in_freq) {
> + set_reg(UART_REG_OFFSET_BRG, UART_BRG_CLK_DIVISOR);
> + set_reg(UART_REG_OFFSET_BRD,
> + uart_min_clk_divisor(in_freq, baudrate));
> + }
> + /* Software reset TX RX data path and enable TX RX */
> + set_reg(UART_REG_OFFSET_CTRL, UART_CR_TXRST | UART_CR_RXRST
> + | UART_CR_TX_EN | UART_CR_RX_EN);
> + /* Set:
> + * 1 stop bit, bits[07:06] = 0x00,
> + * no parity set, bits[05:03] = 0x100,
> + * 8 bits character length, bits[02:01] = 0x00,
> + * sel_clk = uart_clk, bit[0] = 0x0
> + */
> + set_reg(UART_REG_OFFSET_MODE, UART_MR_PARITY_NONE);
> +
> + sbi_console_set_device(&cadence_console);
> +
> + return 0;
> +}
> diff --git a/lib/utils/serial/fdt_serial.c b/lib/utils/serial/fdt_serial.c
> index f73d26a..460f516 100644
> --- a/lib/utils/serial/fdt_serial.c
> +++ b/lib/utils/serial/fdt_serial.c
> @@ -13,6 +13,7 @@
> #include <sbi_utils/fdt/fdt_helper.h>
> #include <sbi_utils/serial/fdt_serial.h>
>
> +extern struct fdt_serial fdt_serial_cadence;
This change is not required.
> extern struct fdt_serial fdt_serial_uart8250;
> extern struct fdt_serial fdt_serial_sifive;
> extern struct fdt_serial fdt_serial_litex;
> @@ -21,6 +22,7 @@ extern struct fdt_serial fdt_serial_shakti;
> extern struct fdt_serial fdt_serial_gaisler;
>
> static struct fdt_serial *serial_drivers[] = {
> + &fdt_serial_cadence,
This change is not required as well.
As-per latest OpenSBI, you just need following two lines
in lib/utils/serial/objects.mk:
carray-fdt_serial_drivers-y += fdt_serial_cadence
libsbiutils-objs-y += serial/fdt_serial_cadence.o
> &fdt_serial_uart8250,
> &fdt_serial_sifive,
> &fdt_serial_litex,
> diff --git a/lib/utils/serial/fdt_serial_cadence.c b/lib/utils/serial/fdt_serial_cadence.c
> new file mode 100644
> index 0000000..f6f13d6
> --- /dev/null
> +++ b/lib/utils/serial/fdt_serial_cadence.c
> @@ -0,0 +1,35 @@
> +/*
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2022 StarFive Technology Co., Ltd.
> + *
> + * Author: Jun Liang Tan <junliang.tan at linux.starfivetech.com>
> + */
> +
> +#include <sbi_utils/fdt/fdt_helper.h>
> +#include <sbi_utils/serial/fdt_serial.h>
> +#include <sbi_utils/serial/cadence-uart.h>
> +
> +static int serial_cadence_init(void *fdt, int nodeoff,
> + const struct fdt_match *match)
> +{
> + int rc;
> + struct platform_uart_data uart;
> +
> + rc = fdt_parse_cadence_uart_node(fdt, nodeoff, &uart);
> + if (rc)
> + return rc;
> +
> + return cadence_uart_init(uart.addr, uart.freq, uart.baud);
> +}
> +
> +static const struct fdt_match serial_cadence_match[] = {
> + { .compatible = "cdns,uart-r1p12" },
> + { .compatible = "starfive,jh8100-uart" },
> + { },
> +};
> +
> +struct fdt_serial fdt_serial_cadence = {
> + .match_table = serial_cadence_match,
> + .init = serial_cadence_init
> +};
> diff --git a/lib/utils/serial/objects.mk b/lib/utils/serial/objects.mk
> index 4f751ba..c201d76 100644
> --- a/lib/utils/serial/objects.mk
> +++ b/lib/utils/serial/objects.mk
> @@ -8,12 +8,14 @@
> #
>
> libsbiutils-objs-y += serial/fdt_serial.o
> +libsbiutils-objs-y += serial/fdt_serial_cadence.o
> libsbiutils-objs-y += serial/fdt_serial_gaisler.o
> libsbiutils-objs-y += serial/fdt_serial_htif.o
> libsbiutils-objs-y += serial/fdt_serial_shakti.o
> libsbiutils-objs-y += serial/fdt_serial_sifive.o
> libsbiutils-objs-y += serial/fdt_serial_litex.o
> libsbiutils-objs-y += serial/fdt_serial_uart8250.o
> +libsbiutils-objs-y += serial/cadence-uart.o
> libsbiutils-objs-y += serial/gaisler-uart.o
> libsbiutils-objs-y += serial/shakti-uart.o
> libsbiutils-objs-y += serial/sifive-uart.o
Please see the above comment. This is not aligned with
latest OpenSBI sources.
Regards,
Anup
> --
> 2.25.1
>
>
>
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