[PATCH] lib: utils: serial: Add Cadence UART driver
Anup Patel
anup at brainfault.org
Fri Jul 8 05:14:24 PDT 2022
On Fri, Jul 8, 2022 at 5:40 PM Anup Patel <anup at brainfault.org> wrote:
>
> 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().
I meant rename fdt_parse_uart8250_node() to fdt_parse_uart_node().
Regards,
Anup
>
> > 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
> >
> >
> >
> > --
> > opensbi mailing list
> > opensbi at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/opensbi
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