From 2d30ccacb12f1f5fd028da857f61f4d511fc5bcb Mon Sep 17 00:00:00 2001 From: Gerhard Sittig Date: Tue, 6 Aug 2013 22:43:42 +0200 Subject: [PATCH] serial: mpc512x: cleanup clock API use cleanup the clock API use of the UART driver which is shared among the MPC512x and the MPC5200 platforms - get, prepare, and enable the MCLK during port allocation; disable, unprepare and put the MCLK upon port release; hold a reference to the clock over the period of use; check for and propagate enable errors - fix a buffer overflow for clock names with two digit PSC index numbers - stick with the PPC_CLOCK 'psc%d_mclk' name for clock lookup, only switch to a fixed string later after device tree based clock lookup will have become available to achieve support for MPC512x which is neutral to MPC5200, the modification was done as follows - introduce "clock alloc" and "clock release" routines in addition to the previous "clock enable/disable" routine in the psc_ops struct - make the clock allocation a part of the port request (resource allocation), and make clock release a part of the port release, such that essential resources get allocated early - just enable/disable the clock from within the .clock() callback without any allocation or preparation as the former implementation did, since this routine is called from within the startup and shutdown callbacks - all of the above remains a NOP for the MPC5200 platform (no callbacks are provided on that platform) - implementation note: the clock gets enabled upon allocation already just in case the clock is not only required for bitrate generation but for register access as well Signed-off-by: Gerhard Sittig Acked-by: Greg Kroah-Hartman Signed-off-by: Anatolij Gustschin --- drivers/tty/serial/mpc52xx_uart.c | 98 +++++++++++++++++++++++++------ 1 file changed, 81 insertions(+), 17 deletions(-) diff --git a/drivers/tty/serial/mpc52xx_uart.c b/drivers/tty/serial/mpc52xx_uart.c index e1280a20b7a2..5be1df39f9f5 100644 --- a/drivers/tty/serial/mpc52xx_uart.c +++ b/drivers/tty/serial/mpc52xx_uart.c @@ -107,6 +107,8 @@ struct psc_ops { unsigned int (*set_baudrate)(struct uart_port *port, struct ktermios *new, struct ktermios *old); + int (*clock_alloc)(struct uart_port *port); + void (*clock_relse)(struct uart_port *port); int (*clock)(struct uart_port *port, int enable); int (*fifoc_init)(void); void (*fifoc_uninit)(void); @@ -616,31 +618,73 @@ static irqreturn_t mpc512x_psc_handle_irq(struct uart_port *port) return IRQ_NONE; } -static int mpc512x_psc_clock(struct uart_port *port, int enable) +static struct clk *psc_mclk_clk[MPC52xx_PSC_MAXNUM]; + +/* called from within the .request_port() callback (allocation) */ +static int mpc512x_psc_alloc_clock(struct uart_port *port) { - struct clk *psc_clk; int psc_num; - char clk_name[10]; + char clk_name[16]; + struct clk *clk; + int err; + + psc_num = (port->mapbase & 0xf00) >> 8; + snprintf(clk_name, sizeof(clk_name), "psc%d_mclk", psc_num); + clk = devm_clk_get(port->dev, clk_name); + if (IS_ERR(clk)) { + dev_err(port->dev, "Failed to get MCLK!\n"); + return PTR_ERR(clk); + } + err = clk_prepare_enable(clk); + if (err) { + dev_err(port->dev, "Failed to enable MCLK!\n"); + return err; + } + psc_mclk_clk[psc_num] = clk; + return 0; +} + +/* called from within the .release_port() callback (release) */ +static void mpc512x_psc_relse_clock(struct uart_port *port) +{ + int psc_num; + struct clk *clk; + + psc_num = (port->mapbase & 0xf00) >> 8; + clk = psc_mclk_clk[psc_num]; + if (clk) { + clk_disable_unprepare(clk); + psc_mclk_clk[psc_num] = NULL; + } +} + +/* implementation of the .clock() callback (enable/disable) */ +static int mpc512x_psc_endis_clock(struct uart_port *port, int enable) +{ + int psc_num; + struct clk *psc_clk; + int ret; if (uart_console(port)) return 0; psc_num = (port->mapbase & 0xf00) >> 8; - snprintf(clk_name, sizeof(clk_name), "psc%d_mclk", psc_num); - psc_clk = clk_get(port->dev, clk_name); - if (IS_ERR(psc_clk)) { + psc_clk = psc_mclk_clk[psc_num]; + if (!psc_clk) { dev_err(port->dev, "Failed to get PSC clock entry!\n"); return -ENODEV; } - dev_dbg(port->dev, "%s %sable\n", clk_name, enable ? "en" : "dis"); - - if (enable) - clk_enable(psc_clk); - else + dev_dbg(port->dev, "mclk %sable\n", enable ? "en" : "dis"); + if (enable) { + ret = clk_enable(psc_clk); + if (ret) + dev_err(port->dev, "Failed to enable MCLK!\n"); + return ret; + } else { clk_disable(psc_clk); - - return 0; + return 0; + } } static void mpc512x_psc_get_irq(struct uart_port *port, struct device_node *np) @@ -873,7 +917,9 @@ static struct psc_ops mpc5125_psc_ops = { .cw_disable_ints = mpc5125_psc_cw_disable_ints, .cw_restore_ints = mpc5125_psc_cw_restore_ints, .set_baudrate = mpc5125_psc_set_baudrate, - .clock = mpc512x_psc_clock, + .clock_alloc = mpc512x_psc_alloc_clock, + .clock_relse = mpc512x_psc_relse_clock, + .clock = mpc512x_psc_endis_clock, .fifoc_init = mpc512x_psc_fifoc_init, .fifoc_uninit = mpc512x_psc_fifoc_uninit, .get_irq = mpc512x_psc_get_irq, @@ -906,7 +952,9 @@ static struct psc_ops mpc512x_psc_ops = { .cw_disable_ints = mpc512x_psc_cw_disable_ints, .cw_restore_ints = mpc512x_psc_cw_restore_ints, .set_baudrate = mpc512x_psc_set_baudrate, - .clock = mpc512x_psc_clock, + .clock_alloc = mpc512x_psc_alloc_clock, + .clock_relse = mpc512x_psc_relse_clock, + .clock = mpc512x_psc_endis_clock, .fifoc_init = mpc512x_psc_fifoc_init, .fifoc_uninit = mpc512x_psc_fifoc_uninit, .get_irq = mpc512x_psc_get_irq, @@ -1166,6 +1214,9 @@ mpc52xx_uart_type(struct uart_port *port) static void mpc52xx_uart_release_port(struct uart_port *port) { + if (psc_ops->clock_relse) + psc_ops->clock_relse(port); + /* remapped by us ? */ if (port->flags & UPF_IOREMAP) { iounmap(port->membase); @@ -1190,11 +1241,24 @@ mpc52xx_uart_request_port(struct uart_port *port) err = request_mem_region(port->mapbase, sizeof(struct mpc52xx_psc), "mpc52xx_psc_uart") != NULL ? 0 : -EBUSY; - if (err && (port->flags & UPF_IOREMAP)) { + if (err) + goto out_membase; + + if (psc_ops->clock_alloc) { + err = psc_ops->clock_alloc(port); + if (err) + goto out_mapregion; + } + + return 0; + +out_mapregion: + release_mem_region(port->mapbase, sizeof(struct mpc52xx_psc)); +out_membase: + if (port->flags & UPF_IOREMAP) { iounmap(port->membase); port->membase = NULL; } - return err; }