clocksource/drivers/cadence_ttc: Convert init function to return error

The init functions do not return any error. They behave as the following:

 - panic, thus leading to a kernel crash while another timer may work and
   make the system boot up correctly

 or

 - print an error and let the caller unaware if the state of the system

Change that by converting the init functions to return an error conforming
to the CLOCKSOURCE_OF_RET prototype.

Proper error handling (rollback, errno value) will be changed later case
by case, thus this change just return back an error or success in the init
function.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Sören Brinkmann <soren.brinkmann@xilinx.com>

diff --git a/drivers/clocksource/cadence_ttc_timer.c b/drivers/clocksource/cadence_ttc_timer.c
index 9be6018bd2b89cc8737e2a3c3e19a277c7eb67ed..e2e76311dde21c7027b76cb661c45a335306cbf7 100644 (file)
--- a/drivers/clocksource/cadence_ttc_timer.c
+++ b/drivers/clocksource/cadence_ttc_timer.c
@@ -322,22 +322,22 @@ static int ttc_rate_change_clocksource_cb(struct notifier_block *nb,
        return NOTIFY_DONE;
 }
 
-static void __init ttc_setup_clocksource(struct clk *clk, void __iomem *base,
+static int __init ttc_setup_clocksource(struct clk *clk, void __iomem *base,
                                         u32 timer_width)
 {
        struct ttc_timer_clocksource *ttccs;
        int err;
 
        ttccs = kzalloc(sizeof(*ttccs), GFP_KERNEL);
-       if (WARN_ON(!ttccs))
-               return;
+       if (!ttccs)
+               return -ENOMEM;
 
        ttccs->ttc.clk = clk;
 
        err = clk_prepare_enable(ttccs->ttc.clk);
-       if (WARN_ON(err)) {
+       if (err) {
                kfree(ttccs);
-               return;
+               return err;
        }
 
        ttccs->ttc.freq = clk_get_rate(ttccs->ttc.clk);
@@ -345,8 +345,10 @@ static void __init ttc_setup_clocksource(struct clk *clk, void __iomem *base,
        ttccs->ttc.clk_rate_change_nb.notifier_call =
                ttc_rate_change_clocksource_cb;
        ttccs->ttc.clk_rate_change_nb.next = NULL;
-       if (clk_notifier_register(ttccs->ttc.clk,
-                               &ttccs->ttc.clk_rate_change_nb))
+
+       err = clk_notifier_register(ttccs->ttc.clk,
+                                   &ttccs->ttc.clk_rate_change_nb);
+       if (err)
                pr_warn("Unable to register clock notifier.\n");
 
        ttccs->ttc.base_addr = base;
@@ -368,14 +370,16 @@ static void __init ttc_setup_clocksource(struct clk *clk, void __iomem *base,
                     ttccs->ttc.base_addr + TTC_CNT_CNTRL_OFFSET);
 
        err = clocksource_register_hz(&ttccs->cs, ttccs->ttc.freq / PRESCALE);
-       if (WARN_ON(err)) {
+       if (err) {
                kfree(ttccs);
-               return;
+               return err;
        }
 
        ttc_sched_clock_val_reg = base + TTC_COUNT_VAL_OFFSET;
        sched_clock_register(ttc_sched_clock_read, timer_width,
                             ttccs->ttc.freq / PRESCALE);
+
+       return 0;
 }
 
 static int ttc_rate_change_clockevent_cb(struct notifier_block *nb,
@@ -401,30 +405,35 @@ static int ttc_rate_change_clockevent_cb(struct notifier_block *nb,
        }
 }
 
-static void __init ttc_setup_clockevent(struct clk *clk,
-                                               void __iomem *base, u32 irq)
+static int __init ttc_setup_clockevent(struct clk *clk,
+                                      void __iomem *base, u32 irq)
 {
        struct ttc_timer_clockevent *ttcce;
        int err;
 
        ttcce = kzalloc(sizeof(*ttcce), GFP_KERNEL);
-       if (WARN_ON(!ttcce))
-               return;
+       if (!ttcce)
+               return -ENOMEM;
 
        ttcce->ttc.clk = clk;
 
        err = clk_prepare_enable(ttcce->ttc.clk);
-       if (WARN_ON(err)) {
+       if (err) {
                kfree(ttcce);
-               return;
+               return err;
        }
 
        ttcce->ttc.clk_rate_change_nb.notifier_call =
                ttc_rate_change_clockevent_cb;
        ttcce->ttc.clk_rate_change_nb.next = NULL;
-       if (clk_notifier_register(ttcce->ttc.clk,
-                               &ttcce->ttc.clk_rate_change_nb))
+
+       err = clk_notifier_register(ttcce->ttc.clk,
+                                   &ttcce->ttc.clk_rate_change_nb);
+       if (err) {
                pr_warn("Unable to register clock notifier.\n");
+               return err;
+       }
+
        ttcce->ttc.freq = clk_get_rate(ttcce->ttc.clk);
 
        ttcce->ttc.base_addr = base;
@@ -451,13 +460,15 @@ static void __init ttc_setup_clockevent(struct clk *clk,
 
        err = request_irq(irq, ttc_clock_event_interrupt,
                          IRQF_TIMER, ttcce->ce.name, ttcce);
-       if (WARN_ON(err)) {
+       if (err) {
                kfree(ttcce);
-               return;
+               return err;
        }
 
        clockevents_config_and_register(&ttcce->ce,
                        ttcce->ttc.freq / PRESCALE, 1, 0xfffe);
+
+       return 0;
 }
 
 /**
@@ -466,17 +477,17 @@ static void __init ttc_setup_clockevent(struct clk *clk,
  * Initializes the timer hardware and register the clock source and clock event
  * timers with Linux kernal timer framework
  */
-static void __init ttc_timer_init(struct device_node *timer)
+static int __init ttc_timer_init(struct device_node *timer)
 {
        unsigned int irq;
        void __iomem *timer_baseaddr;
        struct clk *clk_cs, *clk_ce;
        static int initialized;
-       int clksel;
+       int clksel, ret;
        u32 timer_width = 16;
 
        if (initialized)
-               return;
+               return 0;
 
        initialized = 1;
 
@@ -488,13 +499,13 @@ static void __init ttc_timer_init(struct device_node *timer)
        timer_baseaddr = of_iomap(timer, 0);
        if (!timer_baseaddr) {
                pr_err("ERROR: invalid timer base address\n");
-               BUG();
+               return -ENXIO;
        }
 
        irq = irq_of_parse_and_map(timer, 1);
        if (irq <= 0) {
                pr_err("ERROR: invalid interrupt number\n");
-               BUG();
+               return -EINVAL;
        }
 
        of_property_read_u32(timer, "timer-width", &timer_width);
@@ -504,7 +515,7 @@ static void __init ttc_timer_init(struct device_node *timer)
        clk_cs = of_clk_get(timer, clksel);
        if (IS_ERR(clk_cs)) {
                pr_err("ERROR: timer input clock not found\n");
-               BUG();
+               return PTR_ERR(clk_cs);
        }
 
        clksel = readl_relaxed(timer_baseaddr + 4 + TTC_CLK_CNTRL_OFFSET);
@@ -512,13 +523,20 @@ static void __init ttc_timer_init(struct device_node *timer)
        clk_ce = of_clk_get(timer, clksel);
        if (IS_ERR(clk_ce)) {
                pr_err("ERROR: timer input clock not found\n");
-               BUG();
+               return PTR_ERR(clk_cs);
        }
 
-       ttc_setup_clocksource(clk_cs, timer_baseaddr, timer_width);
-       ttc_setup_clockevent(clk_ce, timer_baseaddr + 4, irq);
+       ret = ttc_setup_clocksource(clk_cs, timer_baseaddr, timer_width);
+       if (ret)
+               return ret;
+
+       ret = ttc_setup_clockevent(clk_ce, timer_baseaddr + 4, irq);
+       if (ret)
+               return ret;
 
        pr_info("%s #0 at %p, irq=%d\n", timer->name, timer_baseaddr, irq);
+
+       return 0;
 }
 
-CLOCKSOURCE_OF_DECLARE(ttc, "cdns,ttc", ttc_timer_init);
+CLOCKSOURCE_OF_DECLARE_RET(ttc, "cdns,ttc", ttc_timer_init);