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Message-ID: <CAMuHMdUVj4y4=cZmtxJj29pCE55YhnL27TWLiBOdvY4Vd98YGA@mail.gmail.com>
Date: Wed, 19 Feb 2025 14:06:25 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Thierry Bultel <thierry.bultel.yh@...renesas.com>
Cc: thierry.bultel@...atsea.fr,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Jiri Slaby <jirislaby@...nel.org>,
linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-serial@...r.kernel.org
Subject: Re: [PATCH v2 08/13] serial: sh-sci: Introduced function pointers
Hi Thierry,
Thanks for your patch!
On Mon, 17 Feb 2025 at 11:56, Thierry Bultel
<thierry.bultel.yh@...renesas.com> wrote:
> The aim here is to prepare support for new sci controllers like
> the T2H/RSCI whose registers are too much different for being
> handled in common code.
>
> This named serial controller also has 32 bits register,
> so some return types had to be changed.
>
> The needed generic functions are no longer static, with prototypes
> defined in sh-sci-common.h so that they can be used from specific
I more like this name than the actual file name "sh-sci_common.h" ;-)
> implementation in a separate file, to keep this driver as little
> changed as possible.
>
> For doing so, a set of 'ops' is added to struct sci_port.
>
> Signed-off-by: Thierry Bultel <thierry.bultel.yh@...renesas.com>
I did a rather thorough review while investigating why this patch
broke SuperH...
> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -76,101 +64,39 @@ enum {
> ((port)->irqs[SCIx_ERI_IRQ] && \
> ((port)->irqs[SCIx_RXI_IRQ] < 0))
>
> -enum SCI_CLKS {
> - SCI_FCK, /* Functional Clock */
> - SCI_SCK, /* Optional External Clock */
> - SCI_BRG_INT, /* Optional BRG Internal Clock Source */
> - SCI_SCIF_CLK, /* Optional BRG External Clock Source */
> - SCI_NUM_CLKS
> -};
> -
> -/* Bit x set means sampling rate x + 1 is supported */
> -#define SCI_SR(x) BIT((x) - 1)
> #define SCI_SR_RANGE(x, y) GENMASK((y) - 1, (x) - 1)
>
> #define SCI_SR_SCIFAB SCI_SR(5) | SCI_SR(7) | SCI_SR(11) | \
> SCI_SR(13) | SCI_SR(16) | SCI_SR(17) | \
> SCI_SR(19) | SCI_SR(27)
>
> -#define min_sr(_port) ffs((_port)->sampling_rate_mask)
> -#define max_sr(_port) fls((_port)->sampling_rate_mask)
> -
> /* Iterate over all supported sampling rates, from high to low */
> #define for_each_sr(_sr, _port) \
> for ((_sr) = max_sr(_port); (_sr) >= min_sr(_port); (_sr)--) \
> if ((_port)->sampling_rate_mask & SCI_SR((_sr)))
>
> -struct plat_sci_reg {
> - u8 offset, size;
> -};
> -
> -struct sci_port_params {
> - const struct plat_sci_reg regs[SCIx_NR_REGS];
This was the sole user of SCIx_NR_REGS, so the latter can be removed.
> - unsigned int fifosize;
> - unsigned int overrun_reg;
> - unsigned int overrun_mask;
> - unsigned int sampling_rate_mask;
> - unsigned int error_mask;
> - unsigned int error_clear;
> -};
> -
> -struct sci_port {
> - struct uart_port port;
> -
> - /* Platform configuration */
> - const struct sci_port_params *params;
> - const struct plat_sci_port *cfg;
> - unsigned int sampling_rate_mask;
> - resource_size_t reg_size;
> - struct mctrl_gpios *gpios;
> -
> - /* Clocks */
> - struct clk *clks[SCI_NUM_CLKS];
> - unsigned long clk_rates[SCI_NUM_CLKS];
> -
> - int irqs[SCIx_NR_IRQS];
> - char *irqstr[SCIx_NR_IRQS];
> -
> - struct dma_chan *chan_tx;
> - struct dma_chan *chan_rx;
> -
> -#ifdef CONFIG_SERIAL_SH_SCI_DMA
> - struct dma_chan *chan_tx_saved;
> - struct dma_chan *chan_rx_saved;
> - dma_cookie_t cookie_tx;
> - dma_cookie_t cookie_rx[2];
> - dma_cookie_t active_rx;
> - dma_addr_t tx_dma_addr;
> - unsigned int tx_dma_len;
> - struct scatterlist sg_rx[2];
> - void *rx_buf[2];
> - size_t buf_len_rx;
> - struct work_struct work_tx;
> - struct hrtimer rx_timer;
> - unsigned int rx_timeout; /* microseconds */
> -#endif
> - unsigned int rx_frame;
> - int rx_trigger;
> - struct timer_list rx_fifo_timer;
> - int rx_fifo_timeout;
> - u16 hscif_tot;
> -
> - bool has_rtscts;
> - bool autorts;
> - bool tx_occurred;
> -};
> -
> #define SCI_NPORTS CONFIG_SERIAL_SH_SCI_NR_UARTS
>
> static struct sci_port sci_ports[SCI_NPORTS];
> static unsigned long sci_ports_in_use;
> static struct uart_driver sci_uart_driver;
>
> -static inline struct sci_port *
> -to_sci_port(struct uart_port *uart)
> -{
> - return container_of(uart, struct sci_port, port);
> -}
> +static const struct sci_port_params_bits sci_sci_port_params_bits = {
> + .rxtx_enable = SCSCR_RE | SCSCR_TE,
> + .te_clear = SCSCR_TE | SCSCR_TEIE,
> + .poll_sent_bits = SCI_FER | SCI_TEND
s/SCI_FER/SCI_TDRE/
Cfr.
#define SCxSR_TDxE(port) (((port)->type == PORT_SCI) ? SCI_TDRE :
SCIF_TDFE)
> +};
> +
> +static const struct sci_port_params_bits sci_scix_port_params_bits = {
I'd rather call this sci_scif_port_params_bits, as it is used by all
SCIF variants (IRDA is sort-of SH3 SCIF).
> + .rxtx_enable = SCSCR_RE | SCSCR_TE,
> + .te_clear = SCSCR_TE | SCSCR_TEIE,
> + .poll_sent_bits = SCIF_TDFE | SCIF_TEND
> +};
> +
> +static const struct sci_common_regs sci_common_regs = {
> + .status = SCxSR,
> + .control = SCSCR,
> +};
>
> static const struct sci_port_params sci_port_params[SCIx_NR_REGTYPES] = {
> /*
> @@ -713,15 +667,16 @@ static void sci_clear_SCxSR(struct uart_port *port, unsigned int mask)
> defined(CONFIG_SERIAL_SH_SCI_EARLYCON)
>
> #ifdef CONFIG_CONSOLE_POLL
> -static int sci_poll_get_char(struct uart_port *port)
> +int sci_poll_get_char(struct uart_port *port)
As rzsci.c does not call this, I think it can stay static...
> {
> unsigned short status;
> + struct sci_port *s = to_sci_port(port);
> int c;
>
> do {
> status = sci_serial_in(port, SCxSR);
> if (status & SCxSR_ERRORS(port)) {
> - sci_clear_SCxSR(port, SCxSR_ERROR_CLEAR(port));
> + s->ops->clear_SCxSR(port, SCxSR_ERROR_CLEAR(port));
> continue;
> }
> break;
> @@ -1623,7 +1582,7 @@ static struct dma_chan *sci_request_dma_chan(struct uart_port *port,
> return chan;
> }
>
> -static void sci_request_dma(struct uart_port *port)
> +void sci_request_dma(struct uart_port *port)
Likewise.
> {
> struct sci_port *s = to_sci_port(port);
> struct tty_port *tport = &port->state->port;
> @@ -1711,7 +1670,7 @@ static void sci_request_dma(struct uart_port *port)
> }
> }
>
> -static void sci_free_dma(struct uart_port *port)
> +void sci_free_dma(struct uart_port *port)
Likewise
> {
> struct sci_port *s = to_sci_port(port);
>
> @@ -1721,7 +1680,7 @@ static void sci_free_dma(struct uart_port *port)
> sci_dma_rx_release(s);
> }
>
> -static void sci_flush_buffer(struct uart_port *port)
> +void sci_flush_buffer(struct uart_port *port)
Not need if rzsci.c does not use DMA yet.
> {
> struct sci_port *s = to_sci_port(port);
>
> @@ -1750,11 +1709,11 @@ static void sci_dma_check_tx_occurred(struct sci_port *s)
> s->tx_occurred = true;
> }
> #else /* !CONFIG_SERIAL_SH_SCI_DMA */
> -static inline void sci_request_dma(struct uart_port *port)
> +inline void sci_request_dma(struct uart_port *port)
Non-static inline?
> {
> }
>
> -static inline void sci_free_dma(struct uart_port *port)
> +inline void sci_free_dma(struct uart_port *port)
Likewise
> {
> }
>
> @@ -1762,7 +1721,9 @@ static void sci_dma_check_tx_occurred(struct sci_port *s)
> {
> }
>
> -#define sci_flush_buffer NULL
> +inline void sci_flush_buffer(struct uart_port *port)
Why?
> +{
> +}
> #endif /* !CONFIG_SERIAL_SH_SCI_DMA */
>
> static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
> @@ -1837,16 +1799,19 @@ static irqreturn_t sci_tx_interrupt(int irq, void *ptr)
> static irqreturn_t sci_tx_end_interrupt(int irq, void *ptr)
> {
> struct uart_port *port = ptr;
> + struct sci_port *s = to_sci_port(port);
> + const struct sci_common_regs *regs = s->params->common_regs;
> unsigned long flags;
> - unsigned short ctrl;
> + u32 ctrl;
>
> if (port->type != PORT_SCI)
> return sci_tx_interrupt(irq, ptr);
>
> uart_port_lock_irqsave(port, &flags);
> - ctrl = sci_serial_in(port, SCSCR);
> - ctrl &= ~(SCSCR_TE | SCSCR_TEIE);
> - sci_serial_out(port, SCSCR, ctrl);
> + ctrl = s->ops->read_reg(port, regs->control);
> +
> + ctrl &= ~(s->params->param_bits->te_clear);
As you only ever use ~te_clear, please move the ~ to the initialization.
> + s->ops->write_reg(port, regs->control, ctrl);
> uart_port_unlock_irqrestore(port, flags);
>
> return IRQ_HANDLED;
> @@ -2059,7 +2025,7 @@ static int sci_request_irq(struct sci_port *port)
> return ret;
> }
>
> -static void sci_free_irq(struct sci_port *port)
> +void sci_free_irq(struct sci_port *port)
As rzsci.c does not call this, I think it can stay static...
> {
> int i, j;
>
> @@ -2232,7 +2198,7 @@ static unsigned int sci_get_mctrl(struct uart_port *port)
> return mctrl;
> }
>
> -static void sci_enable_ms(struct uart_port *port)
> +void sci_enable_ms(struct uart_port *port)
Likewise
> {
> mctrl_gpio_enable_ms(to_sci_port(port)->gpios);
> }
> @@ -2383,9 +2352,9 @@ static int sci_brg_calc(struct sci_port *s, unsigned int bps,
> }
>
> /* calculate sample rate, BRR, and clock select */
> -static int sci_scbrr_calc(struct sci_port *s, unsigned int bps,
> - unsigned int *brr, unsigned int *srr,
> - unsigned int *cks)
> +int sci_scbrr_calc(struct sci_port *s, unsigned int bps,
Likewise.
> + unsigned int *brr, unsigned int *srr,
> + unsigned int *cks)
> {
> unsigned long freq = s->clk_rates[SCI_FCK];
> unsigned int sr, br, prediv, scrate, c;
> @@ -2881,6 +2861,19 @@ static const struct uart_ops sci_uart_ops = {
> #endif
> };
>
> +static const struct sci_port_ops sci_port_ops = {
> + .read_reg = sci_serial_in,
> + .write_reg = sci_serial_out,
> + .receive_chars = sci_receive_chars,
> + .transmit_chars = sci_transmit_chars,
> + .poll_put_char = sci_poll_put_char,
> + .clear_SCxSR = sci_clear_SCxSR,
> + .set_rtrg = scif_set_rtrg,
> + .rtrg_enabled = scif_rtrg_enabled,
> + .shutdown_complete = sci_shutdown_complete,
> + .prepare_console_write = sci_prepare_console_write,
> +};
Please initialize all members in the same order as in the structure's
definition in the header file.
> +
> static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
> {
> const char *clk_names[] = {
> @@ -3119,21 +3115,21 @@ static void serial_console_write(struct console *co, const char *s,
> uart_port_lock_irqsave(port, &flags);
>
> /* first save SCSCR then disable interrupts, keep clock source */
> - ctrl = sci_serial_in(port, SCSCR);
> - ctrl_temp = SCSCR_RE | SCSCR_TE |
> - (sci_port->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0)) |
> - (ctrl & (SCSCR_CKE1 | SCSCR_CKE0));
> - sci_serial_out(port, SCSCR, ctrl_temp | sci_port->hscif_tot);
> +
> + ctrl = sci_port->ops->read_reg(port, regs->control);
> + sci_port->ops->prepare_console_write(port, ctrl);
>
> uart_console_write(port, s, count, serial_console_putchar);
>
> /* wait until fifo is empty and last bit has been transmitted */
> - bits = SCxSR_TDxE(port) | SCxSR_TEND(port);
> - while ((sci_serial_in(port, SCxSR) & bits) != bits)
> +
> + bits = sci_ports->params->param_bits->poll_sent_bits;
s/sci_ports/sci_port/
Else it crashes on e.g. RTS7751R2D (qemu-system-sh4 -M r2d) and Landisk,
where the serial console is ttySC1.
> +
> + while ((sci_port->ops->read_reg(port, regs->status) & bits) != bits)
> cpu_relax();
>
> /* restore the SCSCR */
> - sci_serial_out(port, SCSCR, ctrl);
> + sci_port->ops->write_reg(port, regs->control, ctrl);
>
> if (locked)
> uart_port_unlock_irqrestore(port, flags);
> @@ -3564,9 +3559,11 @@ sh_early_platform_init_buffer("earlyprintk", &sci_driver,
> #ifdef CONFIG_SERIAL_SH_SCI_EARLYCON
> static struct plat_sci_port port_cfg __initdata;
>
> -static int __init early_console_setup(struct earlycon_device *device,
> +int __init early_console_setup(struct earlycon_device *device,
The name of this function is too generic to make it global.
> int type)
> {
> + const struct sci_common_regs *regs;
> +
> if (!device->port.membase)
> return -ENODEV;
>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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