arch/powerpc/platforms/8xx/m8xx_setup.c

Source file repositories/reference/linux-study-clean/arch/powerpc/platforms/8xx/m8xx_setup.c

File Facts

System
Linux kernel
Corpus path
arch/powerpc/platforms/8xx/m8xx_setup.c
Extension
.c
Size
4900 bytes
Lines
173
Domain
Architecture Layer
Bucket
arch/powerpc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

if (fp) {
			found = 1;
			*val = *fp;
		}

		of_node_put(cpu);
	}

	return found;
}

/* The decrementer counts at the system (internal) clock frequency divided by
 * sixteen, or external oscillator divided by four.  We force the processor
 * to use system clock divided by sixteen.
 */
void __init mpc8xx_calibrate_decr(void)
{
	struct device_node *cpu;
	int irq, virq;

	/* Unlock the SCCR. */
	out_be32(&mpc8xx_immr->im_clkrstk.cark_sccrk, ~KAPWR_KEY);
	out_be32(&mpc8xx_immr->im_clkrstk.cark_sccrk, KAPWR_KEY);

	/* Force all 8xx processors to use divide by 16 processor clock. */
	setbits32(&mpc8xx_immr->im_clkrst.car_sccr, 0x02000000);

	/* Processor frequency is MHz.
	 */
	ppc_proc_freq = 50000000;
	if (!get_freq("clock-frequency", &ppc_proc_freq))
		printk(KERN_ERR "WARNING: Estimating processor frequency "
		                "(not found)\n");

	ppc_tb_freq = ppc_proc_freq / 16;
	printk("Decrementer Frequency = 0x%lx\n", ppc_tb_freq);

	/* Perform some more timer/timebase initialization.  This used
	 * to be done elsewhere, but other changes caused it to get
	 * called more than once....that is a bad thing.
	 *
	 * First, unlock all of the registers we are going to modify.
	 * To protect them from corruption during power down, registers
	 * that are maintained by keep alive power are "locked".  To
	 * modify these registers we have to write the key value to
	 * the key location associated with the register.
	 * Some boards power up with these unlocked, while others
	 * are locked.  Writing anything (including the unlock code?)
	 * to the unlocked registers will lock them again.  So, here
	 * we guarantee the registers are locked, then we unlock them
	 * for our use.
	 */
	out_be32(&mpc8xx_immr->im_sitk.sitk_tbscrk, ~KAPWR_KEY);
	out_be32(&mpc8xx_immr->im_sitk.sitk_rtcsck, ~KAPWR_KEY);
	out_be32(&mpc8xx_immr->im_sitk.sitk_tbk, ~KAPWR_KEY);
	out_be32(&mpc8xx_immr->im_sitk.sitk_tbscrk, KAPWR_KEY);
	out_be32(&mpc8xx_immr->im_sitk.sitk_rtcsck, KAPWR_KEY);
	out_be32(&mpc8xx_immr->im_sitk.sitk_tbk, KAPWR_KEY);

	/* Disable the RTC one second and alarm interrupts. */
	clrbits16(&mpc8xx_immr->im_sit.sit_rtcsc, (RTCSC_SIE | RTCSC_ALE));

	/* Enable the RTC */
	setbits16(&mpc8xx_immr->im_sit.sit_rtcsc, (RTCSC_RTF | RTCSC_RTE));

	/* Enabling the decrementer also enables the timebase interrupts
	 * (or from the other point of view, to get decrementer interrupts
	 * we have to enable the timebase).  The decrementer interrupt
	 * is wired into the vector table, nothing to do here for that.
	 */
	cpu = of_get_cpu_node(0, NULL);
	virq= irq_of_parse_and_map(cpu, 0);
	of_node_put(cpu);
	irq = virq_to_hw(virq);

	out_be16(&mpc8xx_immr->im_sit.sit_tbscr,
		 ((1 << (7 - (irq / 2))) << 8) | (TBSCR_TBF | TBSCR_TBE));

	if (request_irq(virq, timebase_interrupt, IRQF_NO_THREAD, "tbint",
			NULL))
		panic("Could not allocate timer IRQ!");
}

/* The RTC on the MPC8xx is an internal register.
 * We want to protect this during power down, so we need to unlock,
 * modify, and re-lock.
 */

int mpc8xx_set_rtc_time(struct rtc_time *tm)
{

Annotation

Implementation Notes