On Sat, Feb 25, 2017 at 12:25:32AM +0100, Andreas Färber wrote: > Am 24.02.2017 um 23:29 schrieb Daniel Lezcano: > > On Fri, Feb 24, 2017 at 04:40:42AM +0100, Andreas Färber wrote: > >> Implement clocksource and clockevents for Actions Semi S500. > >> > >> Based on LeMaker linux-actions tree. > >> > >> Signed-off-by: Andreas Färber <afaer...@suse.de> > > > > As this is a new driver, please give some technical information about the > > driver itself and a pointer to documentation if it is publicly available. > > What technical information would that be? Which of the timers we use as > clock source vs. clock events?
Have a look at commit 07862c1 and e4a6b37 as reference. > The only public documentation beyond the source tree mentioned is here: > > http://www.lemaker.org/product-guitar-download-29.html (section 3.4) > > >> +#define OWL_Tx_CTL_INTEN (1 << 1) > >> +#define OWL_Tx_CTL_EN (1 << 2) > > > > s/(1 << 1)/BIT(1)/ > > s/(1 << 2)/BIT(2)/ > > OK > [ ... ] > >> +static struct clock_event_device owl_clockevent = { > >> + .name = "owl_tick", > >> + .rating = 200, > >> + .features = CLOCK_EVT_FEAT_ONESHOT, > > > > Did you consider adding CLOCK_EVT_FEAT_DYNIRQ ? > > No, it was not present downstream. Got a good example? https://lwn.net/Articles/541000/ > >> + .set_state_shutdown = owl_timer_set_state_shutdown, > >> + .set_state_oneshot = owl_timer_set_state_oneshot, > >> + .tick_resume = owl_timer_tick_resume, > >> + .set_next_event = owl_timer_set_next_event, > >> +}; > >> + > >> +static irqreturn_t owl_timer_interrupt(int irq, void *dev_id) > >> +{ > >> + struct clock_event_device *evt = (struct clock_event_device *)dev_id; > >> + > >> + evt->event_handler(evt); > >> + > >> + return IRQ_HANDLED; > >> +} > >> + > >> +static struct irqaction owl_timer_irq = { > >> + .name = "owl-timer", > >> + .flags = IRQF_TIMER, > >> + .handler = owl_timer_interrupt, > >> + .dev_id = &owl_clockevent, > >> +}; > >> + > >> +static int __init owl_timer_init(struct device_node *node) > >> +{ > >> + const unsigned long rate = 24000000; > > > > Use DT, either use clock-frequency or a clock ref. > > Are clk drivers really available at this point? clock-frequency sounds > more promising. Yes they are. Have a look at the other drivers. > >> + int irq1, ret; > >> + > >> + owl_timer_base = of_io_request_and_map(node, 0, "owl-timer"); > >> + if (IS_ERR(owl_timer_base)) { > >> + pr_err("Can't map timer registers"); > >> + return -ENXIO; > > > > Why not PTR_ERR(owl_timer_base) ? > > Only one in-tree driver (sun5i) matches such an expression. Will change. [ ... ] > > Please factor out these calls into a function. > > Do you have something in particular in mind? Maybe ..._reset() for the > first three? Yes. > >> + > >> + sched_clock_register(owl_timer_sched_read, 32, rate); > >> + clocksource_mmio_init(owl_timer_base + OWL_T0_VAL, node->name, > >> + rate, 200, 32, clocksource_mmio_readl_up); > >> + > >> + writel(0, owl_timer_base + OWL_T1_CTL); > >> + writel(0, owl_timer_base + OWL_T1_VAL); > >> + writel(0, owl_timer_base + OWL_T1_CMP); > >> + > >> + ret = setup_irq(irq1, &owl_timer_irq); > >> + if (ret) { > >> + pr_warn("failed to setup irq %d\n", irq1); > >> + return ret; > >> + } > > > > s/setup_irq/request_irq/ > > Care to explain? setup_irq has 32 hits vs. 28 for request_irq. The function setup_irq takes an irqaction as parameter. That forces all the drivers to declare a structure, so for a multiple platforms support (aka single kernel image), there are multiple structures declaration for nothing. The function request_irq allocates the structure and then call setup_irq. So now, request_irq is used in place of setup_irq. > >> + > >> + owl_clockevent.cpumask = cpumask_of(0); > >> + owl_clockevent.irq = irq1; > >> + > >> + clockevents_config_and_register(&owl_clockevent, rate, > >> + 0xf, 0xffffffff); > >> + > >> + return 0; > >> +} > >> +CLOCKSOURCE_OF_DECLARE(owl, "actions,owl-timer", owl_timer_init); > > Do you spot anything functionally wrong in this driver? Despite adding > this new driver, I am only getting the following additional earlycon output: > > [ 0.000029] sched_clock: 32 bits at 24MHz, resolution 41ns, wraps > every 89478484971ns > [ 0.007888] clocksource: timer: mask: 0xffffffff max_cycles: > 0xffffffff, max_idle_ns: 79635851949 ns > [ 0.017748] Console: colour dummy device 80x30 > [ 0.022243] Calibrating delay loop... > [ 0.030895] random: fast init done > [ 0.231021] random: crng init done > > For S900 I'm using the generic timer instead. I don't get the issue, can you elaborate ? Thanks -- Daniel -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
