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Message-ID: <1300915804.848.40.camel@work-vm>
Date: Wed, 23 Mar 2011 14:30:04 -0700
From: John Stultz <john.stultz@...aro.org>
To: Richard Cochran <richardcochran@...il.com>
Cc: linux-kernel@...r.kernel.org, linux-api@...r.kernel.org,
netdev@...r.kernel.org, devicetree-discuss@...ts.ozlabs.org,
linux-arm-kernel@...ts.infradead.org,
linuxppc-dev@...ts.ozlabs.org, Alan Cox <alan@...rguk.ukuu.org.uk>,
Arnd Bergmann <arnd@...db.de>,
Christoph Lameter <cl@...ux.com>,
David Miller <davem@...emloft.net>,
Krzysztof Halasa <khc@...waw.pl>,
Peter Zijlstra <peterz@...radead.org>,
Rodolfo Giometti <giometti@...ux.it>,
Thomas Gleixner <tglx@...utronix.de>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Mike Frysinger <vapier@...too.org>,
Paul Mackerras <paulus@...ba.org>,
Russell King <linux@....linux.org.uk>
Subject: Re: [PATCH V12 2/4] ptp: Added a clock that uses the eTSEC found
on the MPC85xx.
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
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