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From:   "Hyunki Koo" <hyunki00.koo@samsung.com>
To:     "'Krzysztof Kozlowski'" <krzk@kernel.org>
Cc:     <gregkh@linuxfoundation.org>, "'Kukjin Kim'" <kgene@kernel.org>,
        "'Jiri Slaby'" <jslaby@suse.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-samsung-soc@vger.kernel.org>,
        <linux-serial@vger.kernel.org>, <linux-kernel@vger.kernel.org>
In-Reply-To: <20200403133457.GA7561@kozik-lap>
Subject: RE: [PATCH v4] tty: samsung_tty: 32-bit access for TX/RX hold
 registers
Date:   Mon, 6 Apr 2020 06:41:09 +0900
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References: <20200401082721.19431-1-hyunki00.koo@samsung.com>
        <CGME20200403111520epcas2p42ef81138693ffaaa281499c7a24e0e48@epcas2p4.samsung.com>
        <20200403111511.10598-1-hyunki00.koo@samsung.com>
        <20200403133457.GA7561@kozik-lap>
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On Fri, Apr 03, 2020 at 10:35:10PM +0900, Krzysztof Kozlowski wrote:
> On Fri, Apr 03, 2020 at 08:15:10PM +0900, Hyunki Koo wrote:
> > Support 32-bit access for the TX/RX hold registers UTXH and URXH.
> >
> > This is required for some newer SoCs.
> >
> > Signed-off-by: Hyunki Koo <hyunki00.koo=40samsung.com>
> > ---
> > v2:
> > line 954 : change rd_regl to rd_reg in for backward compatibility.
> > line 2031: Add init value for ourport->port.iotype  to UPIO_MEM
> > v3:
> > line 2031: remove redundant init value  for ourport->port.iotype
> > v4:
> > correct variable types and change misleading function name
> > ---
> >  drivers/tty/serial/samsung_tty.c =7C 76
> > +++++++++++++++++++++++++++++++++-------
> >  1 file changed, 64 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/tty/serial/samsung_tty.c
> > b/drivers/tty/serial/samsung_tty.c
> > index 73f951d65b93..bdf1d4d12cb1 100644
> > --- a/drivers/tty/serial/samsung_tty.c
> > +++ b/drivers/tty/serial/samsung_tty.c
> > =40=40 -154,12 +154,47 =40=40 struct s3c24xx_uart_port =7B  =23define
> > portaddrl(port, reg) =5C
> >  	((unsigned long *)(unsigned long)((port)->membase + (reg)))
> >
> > -=23define rd_regb(port, reg) (readb_relaxed(portaddr(port, reg)))
> > +static u32 rd_reg(struct uart_port *port, u32 reg) =7B
> > +	switch (port->iotype) =7B
> > +	case UPIO_MEM:
> > +		return readb_relaxed(portaddr(port, reg));
> > +	case UPIO_MEM32:
> > +		return readl_relaxed(portaddr(port, reg));
> > +	default:
> > +		return 0;
> > +	=7D
> > +	return 0;
> > +=7D
> > +
> >  =23define rd_regl(port, reg) (readl_relaxed(portaddr(port, reg)))
> >
> > -=23define wr_regb(port, reg, val) writeb_relaxed(val, portaddr(port,
> > reg))
> > +static void wr_reg(struct uart_port *port, u32 reg, u32 val) =7B
> > +	switch (port->iotype) =7B
> > +	case UPIO_MEM:
> > +		writeb_relaxed(val, portaddr(port, reg));
> > +		break;
> > +	case UPIO_MEM32:
> > +		writel_relaxed(val, portaddr(port, reg));
> > +		break;
> > +	=7D
> > +=7D
> > +
> >  =23define wr_regl(port, reg, val) writel_relaxed(val, portaddr(port,
> > reg))
> >
> > +static void wr_reg_barrier(struct uart_port *port, u32 reg, u32 val)
> > +=7B
> > +	switch (port->iotype) =7B
> > +	case UPIO_MEM:
> > +		writeb(val, portaddr(port, reg));
> > +		break;
> > +	case UPIO_MEM32:
> > +		writel(val, portaddr(port, reg));
> > +		break;
> > +	=7D
> > +=7D
> > +
> >  /* Byte-order aware bit setting/clearing functions. */
> >
> >  static inline void s3c24xx_set_bit(struct uart_port *port, int idx,
> > =40=40 -714,7 +749,7 =40=40 static void s3c24xx_serial_rx_drain_fifo(st=
ruct
> s3c24xx_uart_port *ourport)
> >  		fifocnt--;
> >
> >  		uerstat =3D rd_regl(port, S3C2410_UERSTAT);
> > -		ch =3D rd_regb(port, S3C2410_URXH);
> > +		ch =3D rd_reg(port, S3C2410_URXH);
> >
> >  		if (port->flags & UPF_CONS_FLOW) =7B
> >  			int txe =3D s3c24xx_serial_txempty_nofifo(port);
> > =40=40 -826,7 +861,7 =40=40 static irqreturn_t s3c24xx_serial_tx_chars(=
int
> irq, void *id)
> >  	=7D
> >
> >  	if (port->x_char) =7B
> > -		wr_regb(port, S3C2410_UTXH, port->x_char);
> > +		wr_reg(port, S3C2410_UTXH, port->x_char);
> >  		port->icount.tx++;
> >  		port->x_char =3D 0;
> >  		goto out;
> > =40=40 -852,7 +887,7 =40=40 static irqreturn_t s3c24xx_serial_tx_chars(=
int
> irq, void *id)
> >  		if (rd_regl(port, S3C2410_UFSTAT) & ourport->info-
> >tx_fifofull)
> >  			break;
> >
> > -		wr_regb(port, S3C2410_UTXH, xmit->buf=5Bxmit->tail=5D);
> > +		wr_reg(port, S3C2410_UTXH, xmit->buf=5Bxmit->tail=5D);
> >  		xmit->tail =3D (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
> >  		port->icount.tx++;
> >  		count--;
> > =40=40 -916,7 +951,7 =40=40 static unsigned int
> s3c24xx_serial_tx_empty(struct
> > uart_port *port)
> >  /* no modem control lines */
> >  static unsigned int s3c24xx_serial_get_mctrl(struct uart_port *port)
> > =7B
> > -	unsigned int umstat =3D rd_regb(port, S3C2410_UMSTAT);
> > +	unsigned int umstat =3D rd_reg(port, S3C2410_UMSTAT);
> >
> >  	if (umstat & S3C2410_UMSTAT_CTS)
> >  		return TIOCM_CAR =7C TIOCM_DSR =7C TIOCM_CTS; =40=40 -
> 1974,7 +2009,7 =40=40
> > static int s3c24xx_serial_probe(struct platform_device *pdev)
> >  	struct device_node *np =3D pdev->dev.of_node;
> >  	struct s3c24xx_uart_port *ourport;
> >  	int index =3D probe_index;
> > -	int ret;
> > +	int ret, prop =3D 0;
> >
> >  	if (np) =7B
> >  		ret =3D of_alias_get_id(np, =22serial=22); =40=40 -2000,10
> +2035,27 =40=40 static
> > int s3c24xx_serial_probe(struct platform_device *pdev)
> >  			dev_get_platdata(&pdev->dev) :
> >  			ourport->drv_data->def_cfg;
> >
> > -	if (np)
> > +	if (np) =7B
> >  		of_property_read_u32(np,
> >  			=22samsung,uart-fifosize=22, &ourport->port.fifosize);
> >
> > +		if (of_property_read_u32(np, =22reg-io-width=22, &prop) =3D=3D
> 0) =7B
>=20
> I got more thoughts... where is the binding for it? It looked like standa=
rd
> DT property but it is not described in device tree spec.
>=20
> Also, where is the user (DTS) with it? I expect such changes go with the
> user itself... otherwise, next cleanup it will go away.
>=20
> Best regards,
> Krzysztof

Do you think this kind of change is needed?
Do I have to make as a series patches with previous patch?

diff --git a/Documentation/devicetree/bindings/serial/samsung_uart.yaml b/D=
ocumentation/devicetree/bindings/serial/samsung_uart.yaml
index 9d2ce347875b..a57b1233c691 100644
--- a/Documentation/devicetree/bindings/serial/samsung_uart.yaml
+++ b/Documentation/devicetree/bindings/serial/samsung_uart.yaml
=40=40 -29,6 +29,14 =40=40 properties:
   reg:
     maxItems: 1
=20
+  reg-io-width:
+    description: =7C
+      The size (in bytes) of the IO accesses that should be performed
+      on the device.
+    allOf:
+      - =24ref: /schemas/types.yaml=23/definitions/uint32
+      - enum: =5B 1, 4 =5D
+