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tty: serial: samsung: shrink the clock selection to 8 clocks

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<linux/serial_s3c.h> provides a clock selection pool of maximum 4 clocks.
Update the driver to consider a pool selection of maximum 8 clocks.
u8 is large enough to allow more clocks than are supported by the driver
now, and not too big to cause spanning of ``struct s3c24xx_uart_info``
through 2 cachelines when compiled for arm64. The goal is to reduce the
memory footprint of ``struct s3c24xx_uart_info``.

Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/r/20240119104526.1221243-18-tudor.ambarus@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tudor Ambarus 2024-01-19 10:45:24 +00:00 committed by Greg Kroah-Hartman
parent 92e32ed303
commit 6e1e48b6ef
1 changed files with 11 additions and 11 deletions
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22
drivers/tty/serial/samsung_tty.c
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@ -81,11 +81,11 @@ struct s3c24xx_uart_info {
unsigned long tx_fifomask;
unsigned long tx_fifoshift;
unsigned long tx_fifofull;
unsigned int def_clk_sel;
unsigned long num_clks;
unsigned long clksel_mask;
unsigned long clksel_shift;
unsigned long ucon_mask;
u8 def_clk_sel;
u8 num_clks;
u8 iotype;
/* uart port features */
@ -1340,7 +1340,7 @@ static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
#define MAX_CLK_NAME_LENGTH 15
static inline int s3c24xx_serial_getsource(struct uart_port *port)
static inline u8 s3c24xx_serial_getsource(struct uart_port *port)
{
const struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
u32 ucon;
@ -1353,8 +1353,7 @@ static inline int s3c24xx_serial_getsource(struct uart_port *port)
return ucon >> info->clksel_shift;
}
static void s3c24xx_serial_setsource(struct uart_port *port,
unsigned int clk_sel)
static void s3c24xx_serial_setsource(struct uart_port *port, u8 clk_sel)
{
const struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
u32 ucon;
@ -1373,14 +1372,15 @@ static void s3c24xx_serial_setsource(struct uart_port *port,
static unsigned int s3c24xx_serial_getclk(struct s3c24xx_uart_port *ourport,
unsigned int req_baud, struct clk **best_clk,
unsigned int *clk_num)
u8 *clk_num)
{
const struct s3c24xx_uart_info *info = ourport->info;
struct clk *clk;
unsigned long rate;
unsigned int cnt, baud, quot, best_quot = 0;
unsigned int baud, quot, best_quot = 0;
char clkname[MAX_CLK_NAME_LENGTH];
int calc_deviation, deviation = (1 << 30) - 1;
u8 cnt;
for (cnt = 0; cnt < info->num_clks; cnt++) {
/* Keep selected clock if provided */
@ -1473,9 +1473,10 @@ static void s3c24xx_serial_set_termios(struct uart_port *port,
struct s3c24xx_uart_port *ourport = to_ourport(port);
struct clk *clk = ERR_PTR(-EINVAL);
unsigned long flags;
unsigned int baud, quot, clk_sel = 0;
unsigned int baud, quot;
unsigned int udivslot = 0;
u32 ulcon, umcon;
u8 clk_sel = 0;
/*
* We don't support modem control lines.
@ -1776,10 +1777,9 @@ static int s3c24xx_serial_enable_baudclk(struct s3c24xx_uart_port *ourport)
struct device *dev = ourport->port.dev;
const struct s3c24xx_uart_info *info = ourport->info;
char clk_name[MAX_CLK_NAME_LENGTH];
unsigned int clk_sel;
struct clk *clk;
int clk_num;
int ret;
u8 clk_sel, clk_num;
clk_sel = ourport->cfg->clk_sel ? : info->def_clk_sel;
for (clk_num = 0; clk_num < info->num_clks; clk_num++) {
@ -2287,9 +2287,9 @@ s3c24xx_serial_get_options(struct uart_port *port, int *baud,
{
struct clk *clk;
unsigned long rate;
unsigned int clk_sel;
u32 ulcon, ucon, ubrdiv;
char clk_name[MAX_CLK_NAME_LENGTH];
u8 clk_sel;
ulcon = rd_regl(port, S3C2410_ULCON);
ucon = rd_regl(port, S3C2410_UCON);