Re: [PATCH v7 11/12] tty: serial: Add Nuvoton ma35d1 serial driver support
From: Jacky Huang
Date: Sat Apr 15 2023 - 22:32:02 EST
Dear Jiri,
Thanks for you advice.
On 2023/4/14 下午 02:47, Jiri Slaby wrote:
On 12. 04. 23, 7:38, Jacky Huang wrote:
From: Jacky Huang <ychuang3@xxxxxxxxxxx>
This adds UART and console driver for Nuvoton ma35d1 Soc.
It supports full-duplex communication, FIFO control, and
hardware flow control.
Signed-off-by: Jacky Huang <ychuang3@xxxxxxxxxxx>
...
--- /dev/null
+++ b/drivers/tty/serial/ma35d1_serial.c
@@ -0,0 +1,773 @@
...
+static void transmit_chars(struct uart_ma35d1_port *up)
+{
+ int count;
count is unsigned.
I will use 'u32' instead.
+ u8 ch;
+
+ if (uart_tx_stopped(&up->port)) {
+ ma35d1serial_stop_tx(&up->port);
+ return;
+ }
+ count = UART_FIFO_DEPTH - ((serial_in(up, UART_REG_FSR) &
FSR_TXPTR_MSK) >> 16);
So this could be FIELD_GET() while you are defining FSR_TXPTR_MSK
using GENMASK(), right?
Yes, I will modify it as
count = UART_FIFO_DEPTH - FIELD_GET(FSR_TXPTR_MSK, serial_in(up,
UART_REG_FSR));
+ uart_port_tx_limited(&up->port, ch, count,
+ !(serial_in(up, UART_REG_FSR) & FSR_TX_FULL),
+ serial_out(up, UART_REG_THR, ch),
+ ({}));
+}
...
+static void ma35d1serial_set_termios(struct uart_port *port,
+ struct ktermios *termios,
+ const struct ktermios *old)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+ u32 lcr = 0;
+ unsigned long flags;
+ u32 baud, quot;
+
+ lcr = UART_LCR_WLEN(tty_get_char_size(termios->c_cflag));
+
+ if (termios->c_cflag & CSTOPB)
+ lcr |= LCR_NSB;
+ if (termios->c_cflag & PARENB)
+ lcr |= LCR_PBE;
+ if (!(termios->c_cflag & PARODD))
+ lcr |= LCR_EPE;
+ if (termios->c_cflag & CMSPAR)
+ lcr |= LCR_SPE;
+
+ baud = uart_get_baud_rate(port, termios, old, port->uartclk /
0xffff,
+ port->uartclk / 11);
+
+ quot = ma35d1serial_get_divisor(port, baud);
+
+ /*
+ * Ok, we're now changing the port state. Do it with
+ * interrupts disabled.
+ */
+ spin_lock_irqsave(&up->port.lock, flags);
+
+ up->port.read_status_mask = FSR_RX_OVER_IF;
+ if (termios->c_iflag & INPCK)
+ up->port.read_status_mask |= FSR_FEF | FSR_PEF;
+ if (termios->c_iflag & (BRKINT | PARMRK))
+ up->port.read_status_mask |= FSR_BIF;
+
+ /*
+ * Characteres to ignore
"Characters"
The comment could be oneline.
Okay, I will modify it as as oneline.
+ */
+ up->port.ignore_status_mask = 0;
+ if (termios->c_iflag & IGNPAR)
+ up->port.ignore_status_mask |= FSR_FEF | FSR_PEF;
+ if (termios->c_iflag & IGNBRK) {
+ up->port.ignore_status_mask |= FSR_BIF;
+ /*
+ * If we're ignoring parity and break indicators,
+ * ignore overruns too (for real raw support).
+ */
+ if (termios->c_iflag & IGNPAR)
+ up->port.ignore_status_mask |= FSR_RX_OVER_IF;
+ }
Actually I don't understand the "Characteres" comment above at all.
What characters?
We just follow what other serial drivers have done.
You can find the same code segment in tty/serial dz.c, fsl_lpuart.c,
atmel_serial.c, 8250_port.c ....
+ if (termios->c_cflag & CRTSCTS)
+ up->mcr |= UART_MCR_AFE;
+ else
+ up->mcr &= ~UART_MCR_AFE;
+
+ uart_update_timeout(port, termios->c_cflag, baud);
+ ma35d1serial_set_mctrl(&up->port, up->port.mctrl);
+ serial_out(up, UART_REG_BAUD, quot | BAUD_MODE2);
+ serial_out(up, UART_REG_LCR, lcr);
+ spin_unlock_irqrestore(&up->port.lock, flags);
+}
...
+/*
+ * Print a string to the serial port trying not to disturb
+ * any possible real use of the port...
+ *
+ * The console_lock must be held when we get here.
+ */
+static void ma35d1serial_console_write(struct console *co,
+ const char *s, u32 count)
+{
+ struct uart_ma35d1_port *up = &ma35d1serial_ports[co->index];
+ unsigned long flags;
+ u32 ier;
+
+ local_irq_save(flags);
This doesn't protect access to the registers on other CPUs.
We will add spin_lock protect to it.
+
+ /*
+ * First save the IER then disable the interrupts
+ */
+ ier = serial_in(up, UART_REG_IER);
+ serial_out(up, UART_REG_IER, 0);
+
+ uart_console_write(&up->port, s, count,
ma35d1serial_console_putchar);
+
+ wait_for_xmitr(up);
+
+ serial_out(up, UART_REG_IER, ier);
+ local_irq_restore(flags);
+}
+
+static int __init ma35d1serial_console_setup(struct console *co,
+ char *options)
+{
+ struct device_node *np = ma35d1serial_uart_nodes[co->index];
+ struct uart_ma35d1_port *p = &ma35d1serial_ports[co->index];
+ u32 val32[4];
+ struct uart_port *port;
+ int baud = 115200;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
If you don't do uart_parse_options() (why you don't?), you don't need
the variables.
On this platform, the serial console is fixed to be 11520, n, 8, since
booting from
the non-volatile firmware in MaskROM, arm-trust-firmware, uboot. So we
do not
use usrt_parse_options().
I will remove these variables and modify 'uart_set_options(port, co,
baud, parity, bits, flow)'
as 'uart_set_options(port, co, 115200, n, 8, n)'
+ /*
+ * Check whether an invalid uart number has been specified, and
+ * if so, search for the first available port that does have
+ * console support.
+ */
+ if ((co->index < 0) || (co->index >= UART_NR)) {
+ pr_debug("Console Port%x out of range\n", co->index);
+ return -EINVAL;
+ }
+
+ if (of_property_read_u32_array(np, "reg", val32, 4) != 0)
+ return -EINVAL;
+ p->port.iobase = val32[1];
+ p->port.membase = ioremap(p->port.iobase, UART_REG_SIZE);
+ p->port.ops = &ma35d1serial_ops;
+ p->port.line = 0;
+ p->port.uartclk = UART_CONSOLE_CLK;
+
+ port = &ma35d1serial_ports[co->index].port;
+ return uart_set_options(port, co, baud, parity, bits, flow);
+}
...> +static void ma35d1serial_console_init_port(void)
+{
+ int i = 0;
unsigned
I will fix it.
+ struct device_node *np;
+
+ for_each_matching_node(np, ma35d1_serial_of_match) {
+ if (ma35d1serial_uart_nodes[i] == NULL) {
+ of_node_get(np);
+ ma35d1serial_uart_nodes[i] = np;
+ i++;
+ if (i == UART_NR)
+ break;
+ }
+ }
+}
+/*
+ * Register a set of serial devices attached to a platform device.
+ * The list is terminated with a zero flags entry, which means we
expect
+ * all entries to have at least UPF_BOOT_AUTOCONF set.
+ */
+static int ma35d1serial_probe(struct platform_device *pdev)
+{
+ struct resource *res_mem;
+ struct uart_ma35d1_port *up;
+ int ret = 0;
+ struct clk *clk;
+ int err;
+
+ if (pdev->dev.of_node) {
+ ret = of_alias_get_id(pdev->dev.of_node, "serial");
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to get alias/pdev id, errno
%d\n", ret);
+ return ret;
+ }
+ }
+ up = &ma35d1serial_ports[ret];
+ up->port.line = ret;
+ res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res_mem)
+ return -ENODEV;
+
+ up->port.iobase = res_mem->start;
+ up->port.membase = ioremap(up->port.iobase, UART_REG_SIZE);
+ up->port.ops = &ma35d1serial_ops;
+
+ spin_lock_init(&up->port.lock);
+
+ clk = of_clk_get(pdev->dev.of_node, 0);
+ if (IS_ERR(clk)) {
+ err = PTR_ERR(clk);
+ dev_err(&pdev->dev, "failed to get core clk: %d\n", err);
+ return -ENOENT;
iounmap(membase) missing.
I will use devm_ioremap instead, and add return value check to it.
+ }
+ err = clk_prepare_enable(clk);
+ if (err)
+ return -ENOENT;
Dtto.
+
+ if (up->port.line != 0)
+ up->port.uartclk = clk_get_rate(clk);
+ up->port.irq = platform_get_irq(pdev, 0);
What if this fails?
I will add return value check to it.
+ up->port.dev = &pdev->dev;
+ up->port.flags = UPF_BOOT_AUTOCONF;
+ ret = uart_add_one_port(&ma35d1serial_reg, &up->port);
And this?
I will add return value check to it.
+ platform_set_drvdata(pdev, up);
+ return 0;
+}
+
+/*
+ * Remove serial ports registered against a platform device.
+ */
+static int ma35d1serial_remove(struct platform_device *dev)
+{
+ struct uart_port *port = platform_get_drvdata(dev);
+
+ uart_remove_one_port(&ma35d1serial_reg, port);
+ free_irq(port->irq, port);
You do this in ma35d1serial_shutdown() already, correct? So this will
error out, right?
Yes, the free_irq() should be removed. I will fix it.
+ return 0;
+}
Just a couple of questions about testing. Have you tried to:
* remove the module?
* suspend/resume the machine while having a line active (device node
opened)?
* running at least a lockdep-enabled kernel while using the device
extensively?
thanks,
Thank you for the suggestions. Actually, we never remove the serial
driver module.
We will have a test on serial module remove, and test suspend/resume
with at least one uart port enabled.
For the last question, as this SoC have dual-core Cortex-A35 CPU. We
will a test
to run independent uart transfer application on different core.
Best regards,
Jacky Huang