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Date:      Sun, 6 May 2018 14:37:11 +0000 (UTC)
From:      Emmanuel Vadot <manu@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r333305 - head/sys/arm/ti/am335x
Message-ID:  <201805061437.w46EbB1Q004842@repo.freebsd.org>
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Author: manu
Date: Sun May  6 14:37:11 2018
New Revision: 333305
URL: https://svnweb.freebsd.org/changeset/base/333305

Log:
  am335x_prcm: Delay the frequencies read check
  
  With Linux 4.17 dts the compatible for the prcm added 'simplebus' we mean
  that the simplebus driver will attach to it at the BUS_PASS_BUS pass.
  Change the pass for the prcm driver to be at BUS_PASS_BUS so we will win
  the attach.
  This introduce a problem as this driver needs the ti_scm one to be already
  attached. ti_scm also attach at BUS_PASS_BUS but after the prcm one as it is
  after in the dtb and the simplebus driver simpy walk the tree to attach it's
  children.
  Use the bus_new_pass method to defer the frequencies read at BUS_PASS_TIMER.
  This fixes booting on BeagleBone*
  
  Reported by:	many

Modified:
  head/sys/arm/ti/am335x/am335x_prcm.c

Modified: head/sys/arm/ti/am335x/am335x_prcm.c
==============================================================================
--- head/sys/arm/ti/am335x/am335x_prcm.c	Sun May  6 14:19:50 2018	(r333304)
+++ head/sys/arm/ti/am335x/am335x_prcm.c	Sun May  6 14:37:11 2018	(r333305)
@@ -136,6 +136,7 @@ struct am335x_prcm_softc {
 	struct resource *	res[2];
 	bus_space_tag_t		bst;
 	bus_space_handle_t	bsh;
+	int			attach_done;
 };
 
 static struct resource_spec am335x_prcm_spec[] = {
@@ -424,7 +425,6 @@ static int
 am335x_prcm_attach(device_t dev)
 {
 	struct am335x_prcm_softc *sc = device_get_softc(dev);
-	unsigned int sysclk, fclk;
 
 	if (am335x_prcm_sc)
 		return (ENXIO);
@@ -440,6 +440,24 @@ am335x_prcm_attach(device_t dev)
 	am335x_prcm_sc = sc;
 	ti_cpu_reset = am335x_prcm_reset;
 
+	return (0);
+}
+
+static void
+am335x_prcm_new_pass(device_t dev)
+{
+	struct am335x_prcm_softc *sc = device_get_softc(dev);
+	unsigned int sysclk, fclk;
+
+	sc = device_get_softc(dev);
+	if (sc->attach_done ||
+	    bus_current_pass < (BUS_PASS_TIMER + BUS_PASS_ORDER_EARLY)) {
+		bus_generic_new_pass(dev);
+		return;
+	}
+
+	sc->attach_done = 1;
+
 	if (am335x_clk_get_sysclk_freq(NULL, &sysclk) != 0)
 		sysclk = 0;
 	if (am335x_clk_get_arm_fclk_freq(NULL, &fclk) != 0)
@@ -447,15 +465,24 @@ am335x_prcm_attach(device_t dev)
 	if (sysclk && fclk)
 		device_printf(dev, "Clocks: System %u.%01u MHz, CPU %u MHz\n",
 		    sysclk/1000000, (sysclk % 1000000)/100000, fclk/1000000);
-	else
+	else {
 		device_printf(dev, "can't read frequencies yet (SCM device not ready?)\n");
+		goto fail;
+	}
 
-	return (0);
+	return;
+
+fail:
+	device_detach(dev);
+	return;
 }
 
 static device_method_t am335x_prcm_methods[] = {
 	DEVMETHOD(device_probe,		am335x_prcm_probe),
 	DEVMETHOD(device_attach,	am335x_prcm_attach),
+
+	/* Bus interface */
+	DEVMETHOD(bus_new_pass,		am335x_prcm_new_pass),
 	{ 0, 0 }
 };
 
@@ -468,7 +495,7 @@ static driver_t am335x_prcm_driver = {
 static devclass_t am335x_prcm_devclass;
 
 EARLY_DRIVER_MODULE(am335x_prcm, simplebus, am335x_prcm_driver,
-	am335x_prcm_devclass, 0, 0, BUS_PASS_TIMER + BUS_PASS_ORDER_EARLY);
+	am335x_prcm_devclass, 0, 0, BUS_PASS_BUS + BUS_PASS_ORDER_MIDDLE);
 MODULE_VERSION(am335x_prcm, 1);
 MODULE_DEPEND(am335x_prcm, ti_scm, 1, 1, 1);

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