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

Jiri Slaby (SUSE)
2025-06-11T10:03:29Z

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