lkml.org 
[lkml]   [2011]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH V12 2/4] ptp: Added a clock that uses the eTSEC found on the MPC85xx.
    From
    Date
    On Mon, 2011-02-28 at 08:57 +0100, Richard Cochran wrote:
    > The eTSEC includes a PTP clock with quite a few features. This patch adds
    > support for the basic clock adjustment functions, plus two external time
    > stamps, one alarm, and the PPS callback.

    Just a minor question on the locking, but otherwise looks ok.

    > --- /dev/null
    > +++ b/drivers/net/gianfar_ptp.c
    > @@ -0,0 +1,579 @@
    [snip]
    > +/*
    > + * Register access functions
    > + */

    So what are the locking rules on the functions below? I assume the
    etsects->lock needs to be held prior to calling, so that should be made
    explicit in a comment.

    > +static u64 tmr_cnt_read(struct etsects *etsects)
    > +{
    > + u64 ns;
    > + u32 lo, hi;
    > +
    > + lo = gfar_read(&etsects->regs->tmr_cnt_l);
    > + hi = gfar_read(&etsects->regs->tmr_cnt_h);
    > + ns = ((u64) hi) << 32;
    > + ns |= lo;
    > + return ns;
    > +}
    > +
    > +static void tmr_cnt_write(struct etsects *etsects, u64 ns)
    > +{
    > + u32 hi = ns >> 32;
    > + u32 lo = ns & 0xffffffff;
    > +
    > + gfar_write(&etsects->regs->tmr_cnt_l, lo);
    > + gfar_write(&etsects->regs->tmr_cnt_h, hi);
    > +}
    > +
    > +static void set_alarm(struct etsects *etsects)
    > +{
    > + u64 ns;
    > + u32 lo, hi;
    > +
    > + ns = tmr_cnt_read(etsects) + 1500000000ULL;
    > + ns = div_u64(ns, 1000000000UL) * 1000000000ULL;
    > + ns -= etsects->tclk_period;
    > + hi = ns >> 32;
    > + lo = ns & 0xffffffff;
    > + gfar_write(&etsects->regs->tmr_alarm1_l, lo);
    > + gfar_write(&etsects->regs->tmr_alarm1_h, hi);
    > +}
    > +
    > +static void set_fipers(struct etsects *etsects)
    > +{
    > + u32 tmr_ctrl = gfar_read(&etsects->regs->tmr_ctrl);
    > +
    > + gfar_write(&etsects->regs->tmr_ctrl, tmr_ctrl & (~TE));
    > + gfar_write(&etsects->regs->tmr_prsc, etsects->tmr_prsc);
    > + gfar_write(&etsects->regs->tmr_fiper1, etsects->tmr_fiper1);
    > + gfar_write(&etsects->regs->tmr_fiper2, etsects->tmr_fiper2);
    > + set_alarm(etsects);
    > + gfar_write(&etsects->regs->tmr_ctrl, tmr_ctrl|TE);
    > +}
    > +

    [snip]

    > +static int gianfar_ptp_probe(struct platform_device *dev)
    > +{
    > + struct device_node *node = dev->dev.of_node;
    > + struct etsects *etsects;
    > + struct timespec now;
    > + int err = -ENOMEM;
    > + u32 tmr_ctrl;
    > +
    > + etsects = kzalloc(sizeof(*etsects), GFP_KERNEL);
    > + if (!etsects)
    > + goto no_memory;
    > +
    > + err = -ENODEV;
    > +
    > + etsects->caps = ptp_gianfar_caps;
    > + etsects->cksel = DEFAULT_CKSEL;
    > +
    > + if (get_of_u32(node, "fsl,tclk-period", &etsects->tclk_period) ||
    > + get_of_u32(node, "fsl,tmr-prsc", &etsects->tmr_prsc) ||
    > + get_of_u32(node, "fsl,tmr-add", &etsects->tmr_add) ||
    > + get_of_u32(node, "fsl,tmr-fiper1", &etsects->tmr_fiper1) ||
    > + get_of_u32(node, "fsl,tmr-fiper2", &etsects->tmr_fiper2) ||
    > + get_of_u32(node, "fsl,max-adj", &etsects->caps.max_adj)) {
    > + pr_err("device tree node missing required elements\n");
    > + goto no_node;
    > + }
    > +
    > + etsects->irq = platform_get_irq(dev, 0);
    > +
    > + if (etsects->irq == NO_IRQ) {
    > + pr_err("irq not in device tree\n");
    > + goto no_node;
    > + }
    > + if (request_irq(etsects->irq, isr, 0, DRIVER, etsects)) {
    > + pr_err("request_irq failed\n");
    > + goto no_node;
    > + }
    > +
    > + etsects->rsrc = platform_get_resource(dev, IORESOURCE_MEM, 0);
    > + if (!etsects->rsrc) {
    > + pr_err("no resource\n");
    > + goto no_resource;
    > + }
    > + if (request_resource(&ioport_resource, etsects->rsrc)) {
    > + pr_err("resource busy\n");
    > + goto no_resource;
    > + }
    > +
    > + spin_lock_init(&etsects->lock);
    > +
    > + etsects->regs = ioremap(etsects->rsrc->start,
    > + 1 + etsects->rsrc->end - etsects->rsrc->start);
    > + if (!etsects->regs) {
    > + pr_err("ioremap ptp registers failed\n");
    > + goto no_ioremap;
    > + }
    > + getnstimeofday(&now);
    > + ptp_gianfar_settime(&etsects->caps, &now);
    > +
    > + tmr_ctrl =
    > + (etsects->tclk_period & TCLK_PERIOD_MASK) << TCLK_PERIOD_SHIFT |
    > + (etsects->cksel & CKSEL_MASK) << CKSEL_SHIFT;
    > +
    > + gfar_write(&etsects->regs->tmr_ctrl, tmr_ctrl);
    > + gfar_write(&etsects->regs->tmr_add, etsects->tmr_add);
    > + gfar_write(&etsects->regs->tmr_prsc, etsects->tmr_prsc);
    > + gfar_write(&etsects->regs->tmr_fiper1, etsects->tmr_fiper1);
    > + gfar_write(&etsects->regs->tmr_fiper2, etsects->tmr_fiper2);
    > + set_alarm(etsects);
    > + gfar_write(&etsects->regs->tmr_ctrl, tmr_ctrl|FS|RTPE|TE);

    Does any of the above need a lock should an irq land in the middle of
    the writes?



    thanks
    -john




    \
     
     \ /
      Last update: 2011-03-23 22:33    [W:0.032 / U:1.772 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site