Neither registers shadowing is functionally needed as all the registers are
read-write, nor the shadowing makes much sense for speed-up, as most speed
critical reads/writes (of data Rx/Tx registers) are not shadowed anyway.
Moreover, the shadowing code is obviously pure overhead on the write path.
Get rid of the shadowing code and variables due to above considerations.
Signed-off-by: Sergey Organov <sorganov@xxxxxxxxx>
---
NOTE: This patch is extracted from patch series "[PATCH 0/8] serial: imx:
work-around for hardware RX flood, and then isr improvements" due to
objection of Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>. I still
believe this is an improvement, so I re-submit the patch separately.
drivers/tty/serial/imx.c | 65 ++--------------------------------------
1 file changed, 3 insertions(+), 62 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 757825edb0cd..f4e2db21d0fe 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -210,13 +210,6 @@ struct imx_port {
struct mctrl_gpios *gpios;
- /* shadow registers */
- unsigned int ucr1;
- unsigned int ucr2;
- unsigned int ucr3;
- unsigned int ucr4;
- unsigned int ufcr;
-
/* DMA fields */
unsigned int dma_is_enabled:1;
unsigned int dma_is_rxing:1;
@@ -273,59 +266,14 @@ static const struct of_device_id imx_uart_dt_ids[] = {
};
MODULE_DEVICE_TABLE(of, imx_uart_dt_ids);
-static void imx_uart_writel(struct imx_port *sport, u32 val, u32 offset)
+static inline void imx_uart_writel(struct imx_port *sport, u32 val, u32 offset)
{
- switch (offset) {
- case UCR1:
- sport->ucr1 = val;
- break;
- case UCR2:
- sport->ucr2 = val;
- break;
- case UCR3:
- sport->ucr3 = val;
- break;
- case UCR4:
- sport->ucr4 = val;
- break;
- case UFCR:
- sport->ufcr = val;
- break;
- default:
- break;
- }
writel(val, sport->port.membase + offset);
}
-static u32 imx_uart_readl(struct imx_port *sport, u32 offset)
+static inline u32 imx_uart_readl(struct imx_port *sport, u32 offset)
{
- switch (offset) {
- case UCR1:
- return sport->ucr1;
- break;
- case UCR2:
- /*
- * UCR2_SRST is the only bit in the cached registers that might
- * differ from the value that was last written. As it only
- * automatically becomes one after being cleared, reread
- * conditionally.
- */
- if (!(sport->ucr2 & UCR2_SRST))
- sport->ucr2 = readl(sport->port.membase + offset);
- return sport->ucr2;
- break;
- case UCR3:
- return sport->ucr3;
- break;
- case UCR4:
- return sport->ucr4;
- break;
- case UFCR:
- return sport->ufcr;
- break;
- default:
- return readl(sport->port.membase + offset);
- }
+ return readl(sport->port.membase + offset);
}
static inline unsigned imx_uart_uts_reg(struct imx_port *sport)
@@ -2340,13 +2288,6 @@ static int imx_uart_probe(struct platform_device *pdev)
return ret;
}
- /* initialize shadow register values */
- sport->ucr1 = readl(sport->port.membase + UCR1);
- sport->ucr2 = readl(sport->port.membase + UCR2);
- sport->ucr3 = readl(sport->port.membase + UCR3);
- sport->ucr4 = readl(sport->port.membase + UCR4);
- sport->ufcr = readl(sport->port.membase + UFCR);
-
ret = uart_get_rs485_mode(&sport->port);
if (ret) {
clk_disable_unprepare(sport->clk_ipg);
base-commit: 40c18f363a0806d4f566e8a9a9bd2d7766a72cf5
--
2.30.1
