[PATCH 02/33] powerpc/legacy_serial: cache serial port and info in add_legacy_port()

Jiri Slaby (SUSE) posted 33 patches 4 months ago
[PATCH 02/33] powerpc/legacy_serial: cache serial port and info in add_legacy_port()
Posted by Jiri Slaby (SUSE) 4 months ago
Caching the port and info in local variables makes the code more compact
and easier to understand.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/kernel/legacy_serial.c | 52 ++++++++++++++---------------
 1 file changed, 26 insertions(+), 26 deletions(-)

diff --git a/arch/powerpc/kernel/legacy_serial.c b/arch/powerpc/kernel/legacy_serial.c
index 1da2f6e7d2a1..d9080189c28c 100644
--- a/arch/powerpc/kernel/legacy_serial.c
+++ b/arch/powerpc/kernel/legacy_serial.c
@@ -77,6 +77,8 @@ static int __init add_legacy_port(struct device_node *np, int want_index,
 				  phys_addr_t taddr, unsigned long irq,
 				  upf_t flags, int irq_check_parent)
 {
+	struct plat_serial8250_port *legacy_port;
+	struct legacy_serial_info *legacy_info;
 	const __be32 *clk, *spd, *rs;
 	u32 clock = BASE_BAUD * 16;
 	u32 shift = 0;
@@ -110,16 +112,17 @@ static int __init add_legacy_port(struct device_node *np, int want_index,
 	if (index >= legacy_serial_count)
 		legacy_serial_count = index + 1;
 
+	legacy_port = &legacy_serial_ports[index];
+	legacy_info = &legacy_serial_infos[index];
+
 	/* Check if there is a port who already claimed our slot */
-	if (legacy_serial_infos[index].np != NULL) {
+	if (legacy_info->np != NULL) {
 		/* if we still have some room, move it, else override */
 		if (legacy_serial_count < MAX_LEGACY_SERIAL_PORTS) {
 			printk(KERN_DEBUG "Moved legacy port %d -> %d\n",
 			       index, legacy_serial_count);
-			legacy_serial_ports[legacy_serial_count] =
-				legacy_serial_ports[index];
-			legacy_serial_infos[legacy_serial_count] =
-				legacy_serial_infos[index];
+			legacy_serial_ports[legacy_serial_count] = *legacy_port;
+			legacy_serial_infos[legacy_serial_count] = *legacy_info;
 			legacy_serial_count++;
 		} else {
 			printk(KERN_DEBUG "Replacing legacy port %d\n", index);
@@ -127,36 +130,33 @@ static int __init add_legacy_port(struct device_node *np, int want_index,
 	}
 
 	/* Now fill the entry */
-	memset(&legacy_serial_ports[index], 0,
-	       sizeof(struct plat_serial8250_port));
+	memset(legacy_port, 0, sizeof(*legacy_port));
 	if (iotype == UPIO_PORT)
-		legacy_serial_ports[index].iobase = base;
+		legacy_port->iobase = base;
 	else
-		legacy_serial_ports[index].mapbase = base;
-
-	legacy_serial_ports[index].iotype = iotype;
-	legacy_serial_ports[index].uartclk = clock;
-	legacy_serial_ports[index].irq = irq;
-	legacy_serial_ports[index].flags = flags;
-	legacy_serial_ports[index].regshift = shift;
-	legacy_serial_infos[index].taddr = taddr;
-	legacy_serial_infos[index].np = of_node_get(np);
-	legacy_serial_infos[index].clock = clock;
-	legacy_serial_infos[index].speed = spd ? be32_to_cpup(spd) : 0;
-	legacy_serial_infos[index].irq_check_parent = irq_check_parent;
+		legacy_port->mapbase = base;
+
+	legacy_port->iotype = iotype;
+	legacy_port->uartclk = clock;
+	legacy_port->irq = irq;
+	legacy_port->flags = flags;
+	legacy_port->regshift = shift;
+	legacy_info->taddr = taddr;
+	legacy_info->np = of_node_get(np);
+	legacy_info->clock = clock;
+	legacy_info->speed = spd ? be32_to_cpup(spd) : 0;
+	legacy_info->irq_check_parent = irq_check_parent;
 
 	if (iotype == UPIO_TSI) {
-		legacy_serial_ports[index].serial_in = tsi_serial_in;
-		legacy_serial_ports[index].serial_out = tsi_serial_out;
+		legacy_port->serial_in = tsi_serial_in;
+		legacy_port->serial_out = tsi_serial_out;
 	}
 
-	printk(KERN_DEBUG "Found legacy serial port %d for %pOF\n",
-	       index, np);
+	printk(KERN_DEBUG "Found legacy serial port %d for %pOF\n", index, np);
 	printk(KERN_DEBUG "  %s=%llx, taddr=%llx, irq=%lx, clk=%d, speed=%d\n",
 	       (iotype == UPIO_PORT) ? "port" : "mem",
 	       (unsigned long long)base, (unsigned long long)taddr, irq,
-	       legacy_serial_ports[index].uartclk,
-	       legacy_serial_infos[index].speed);
+	       legacy_port->uartclk, legacy_info->speed);
 
 	return index;
 }
-- 
2.49.0
Re: [PATCH 02/33] powerpc/legacy_serial: cache serial port and info in add_legacy_port()
Posted by Ilpo Järvinen 4 months ago
On Wed, 11 Jun 2025, Jiri Slaby (SUSE) wrote:

> Caching the port and info in local variables makes the code more compact
> and easier to understand.
> 
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
> Cc: linuxppc-dev@lists.ozlabs.org

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

--
 i.

> ---
>  arch/powerpc/kernel/legacy_serial.c | 52 ++++++++++++++---------------
>  1 file changed, 26 insertions(+), 26 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/legacy_serial.c b/arch/powerpc/kernel/legacy_serial.c
> index 1da2f6e7d2a1..d9080189c28c 100644
> --- a/arch/powerpc/kernel/legacy_serial.c
> +++ b/arch/powerpc/kernel/legacy_serial.c
> @@ -77,6 +77,8 @@ static int __init add_legacy_port(struct device_node *np, int want_index,
>  				  phys_addr_t taddr, unsigned long irq,
>  				  upf_t flags, int irq_check_parent)
>  {
> +	struct plat_serial8250_port *legacy_port;
> +	struct legacy_serial_info *legacy_info;
>  	const __be32 *clk, *spd, *rs;
>  	u32 clock = BASE_BAUD * 16;
>  	u32 shift = 0;
> @@ -110,16 +112,17 @@ static int __init add_legacy_port(struct device_node *np, int want_index,
>  	if (index >= legacy_serial_count)
>  		legacy_serial_count = index + 1;
>  
> +	legacy_port = &legacy_serial_ports[index];
> +	legacy_info = &legacy_serial_infos[index];
> +
>  	/* Check if there is a port who already claimed our slot */
> -	if (legacy_serial_infos[index].np != NULL) {
> +	if (legacy_info->np != NULL) {
>  		/* if we still have some room, move it, else override */
>  		if (legacy_serial_count < MAX_LEGACY_SERIAL_PORTS) {
>  			printk(KERN_DEBUG "Moved legacy port %d -> %d\n",
>  			       index, legacy_serial_count);
> -			legacy_serial_ports[legacy_serial_count] =
> -				legacy_serial_ports[index];
> -			legacy_serial_infos[legacy_serial_count] =
> -				legacy_serial_infos[index];
> +			legacy_serial_ports[legacy_serial_count] = *legacy_port;
> +			legacy_serial_infos[legacy_serial_count] = *legacy_info;
>  			legacy_serial_count++;
>  		} else {
>  			printk(KERN_DEBUG "Replacing legacy port %d\n", index);
> @@ -127,36 +130,33 @@ static int __init add_legacy_port(struct device_node *np, int want_index,
>  	}
>  
>  	/* Now fill the entry */
> -	memset(&legacy_serial_ports[index], 0,
> -	       sizeof(struct plat_serial8250_port));
> +	memset(legacy_port, 0, sizeof(*legacy_port));
>  	if (iotype == UPIO_PORT)
> -		legacy_serial_ports[index].iobase = base;
> +		legacy_port->iobase = base;
>  	else
> -		legacy_serial_ports[index].mapbase = base;
> -
> -	legacy_serial_ports[index].iotype = iotype;
> -	legacy_serial_ports[index].uartclk = clock;
> -	legacy_serial_ports[index].irq = irq;
> -	legacy_serial_ports[index].flags = flags;
> -	legacy_serial_ports[index].regshift = shift;
> -	legacy_serial_infos[index].taddr = taddr;
> -	legacy_serial_infos[index].np = of_node_get(np);
> -	legacy_serial_infos[index].clock = clock;
> -	legacy_serial_infos[index].speed = spd ? be32_to_cpup(spd) : 0;
> -	legacy_serial_infos[index].irq_check_parent = irq_check_parent;
> +		legacy_port->mapbase = base;
> +
> +	legacy_port->iotype = iotype;
> +	legacy_port->uartclk = clock;
> +	legacy_port->irq = irq;
> +	legacy_port->flags = flags;
> +	legacy_port->regshift = shift;
> +	legacy_info->taddr = taddr;
> +	legacy_info->np = of_node_get(np);
> +	legacy_info->clock = clock;
> +	legacy_info->speed = spd ? be32_to_cpup(spd) : 0;
> +	legacy_info->irq_check_parent = irq_check_parent;
>  
>  	if (iotype == UPIO_TSI) {
> -		legacy_serial_ports[index].serial_in = tsi_serial_in;
> -		legacy_serial_ports[index].serial_out = tsi_serial_out;
> +		legacy_port->serial_in = tsi_serial_in;
> +		legacy_port->serial_out = tsi_serial_out;
>  	}
>  
> -	printk(KERN_DEBUG "Found legacy serial port %d for %pOF\n",
> -	       index, np);
> +	printk(KERN_DEBUG "Found legacy serial port %d for %pOF\n", index, np);
>  	printk(KERN_DEBUG "  %s=%llx, taddr=%llx, irq=%lx, clk=%d, speed=%d\n",
>  	       (iotype == UPIO_PORT) ? "port" : "mem",
>  	       (unsigned long long)base, (unsigned long long)taddr, irq,
> -	       legacy_serial_ports[index].uartclk,
> -	       legacy_serial_infos[index].speed);
> +	       legacy_port->uartclk, legacy_info->speed);
>  
>  	return index;
>  }
>