dt-bindings: simplefb: Specify node location and handoff related properties

Since simplefb nodes do not relate directly to hw typically they have been
placed in the root of the devicetree. As the represent runtime information
having them as sub-nodes of /chosen is more logical, specify this.

Also specify when to set the chosen stdout-path property to a simplefb node.

For reliable handover to a hardware specific driver, that driver needs to
know which simplefb to unregister when taking over, specify how the hw driver
can find the matching simplefb node.

Last add some advice on how to fill and use simplefb nodes from a firmware
pov.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
--
Changes in v2:
-Add stdout-path to the example code
Changes in v3:
-Specify that the node name must be "framebuffer@<address>"
-Specify that the link to link simplefb node and display hw noded to one
 another for handover goes into the simplefb node, and must be called "display"
-Specify how aliases may be used to tell the OS how to number displays
-Update the example to reflect these changes
simplefb: Add support for enumerating simplefb dt nodes in /chosen

Update simplefb to support the new preferred location for simplefb dt nodes
under /chosen.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
--
Changes in v2:
-Make name array larger in case we ever encounter more then 10000 framebuffers
Changes in v3:
-Switch to for_each_child_of_node to loop over the nodes under chosen
simplefb: Change simplefb_init from module_init to fs_initcall

One of the reasons for having the simplefb nodes in /chosen, and doing
explicit enumeration of the nodes there, is too allow enumerating them sooner,
so that we get a console earlier on.

Doing this earlier then fs_initcall is not useful, since the fb only turns into
a console when fbcon intializes, which is a fs_initcall too.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Grant Likely <grant.likely@linaro.org>
fbcon: Change fbcon_init from module_init to fs_initcall

Various fb drivers register themselves before module_init so as to have a
console as early as possible, this is of little use if fbcon does not initialze
early too.

Fbcon cannot initialize earlier then fs_initcall, because then the creation
of /sys/class/graphics/fbcon will fail.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
phy-sun4i-usb: Change disconnect threshold value for sun6i

The allwinner SDK usesa  value of 3 for the disconnect threshold setting on
sun6i, do the same in the kernel.

In my previous experience with sun5i problems getting the threshold right
is important to avoid usb devices being unplugged sometimes going unnoticed.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: dts: sunxi: Add regulator-boot-on property to ahci-5v regulator

This avoids it getting briefly turned off between when the regulator getting
registered and the ahci driver turning it back on, thus avoiding the disk
going into emergency head park mode.

Cc: Bruno Prémont <bonbons@linux-vserver.org>
Reported-and-tested-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: dts: sun4i: Add simplefb node

Add a simplefb template node for u-boot to further fill and activate.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: dts: sun5i: Add simplefb node

Add a simplefb template node for u-boot to further fill and activate.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: dts: sun6i: Add simplefb node

Add a simplefb template node for u-boot to further fill and activate.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: dts: sun7i: Add simplefb node

Add a simplefb template node for u-boot to further fill and activate.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: dts: sun6i: Add EHCI support for the M9 board

The Mele M9 / A1000G quad uses both usb-ports, one goes to an internal
usb wifi card, the other to a build-in usb-hub, so neither need their
OHCI companion controller to be enabled since the are always connected at
USB-2 speeds.

The controller which is attached to the wifi also does not need a vbus
regulator.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: dts: sun6i: Add support for the status led

The Mele M9 / A1000G quad has a blue status led, add support for this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
AHCI: Fix threaded interrupt setup

Commit 18dcf433f3de (AHCI: Optimize single IRQ interrupt processing)
switched the single IRQ case of the AHCI driver to use threaded
threaded interrupts.

During this conversion, only the IRQF_SHARED flag was provided. The net
effect of this in the presence of level interrupts is that the
interrupt will not be masked during the execution of the treaded
handler, leading to a screaming interrupt if the thread is not
scheduled quickly enough, specially in error conditions:

[    2.728051] ahci-sunxi 1c18000.sata: controller can't do PMP, turning off CAP_PMP
[    2.735578] ahci-sunxi 1c18000.sata: SSS flag set, parallel bus scan disabled
[    2.742792] ahci-sunxi 1c18000.sata: AHCI 0001.0100 32 slots 1 ports 3 Gbps 0x1 impl platform mode
[    2.751789] ahci-sunxi 1c18000.sata: flags: ncq sntf stag pm led clo only pio slum part ccc
[    2.761539] scsi host0: ahci_platform
[    2.765754] ata1: SATA max UDMA/133 mmio [mem 0x01c18000-0x01c18fff] port 0x100 irq 88
[...]
[    3.127977] ata1: SATA link down (SStatus 0 SControl 300)
[...]
[    3.162035] Waiting for root device /dev/sda1...
[    3.163700] random: nonblocking pool is initialized
[    3.326593] irq 88: nobody cared (try booting with the "irqpoll" option)
[    3.333296] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.18.0-rc1+ #3077
[    3.339936] [<c002b318>] (unwind_backtrace) from [<c0026980>] (show_stack+0x20/0x24)
[    3.347681] [<c0026980>] (show_stack) from [<c067dd18>] (dump_stack+0x9c/0xd4)
[    3.354904] [<c067dd18>] (dump_stack) from [<c007ac08>] (__report_bad_irq+0x38/0xd4)
[    3.362643] [<c007ac08>] (__report_bad_irq) from [<c007b1dc>] (note_interrupt+0x280/0x2d0)
[    3.370903] [<c007b1dc>] (note_interrupt) from [<c0078a70>] (handle_irq_event_percpu+0x210/0x27c)
[    3.379771] [<c0078a70>] (handle_irq_event_percpu) from [<c0078b28>] (handle_irq_event+0x4c/0x6c)
[    3.388636] [<c0078b28>] (handle_irq_event) from [<c007b860>] (handle_fasteoi_irq+0xbc/0x1a0)
[    3.397156] [<c007b860>] (handle_fasteoi_irq) from [<c0077f5c>] (generic_handle_irq+0x3c/0x4c)
[    3.405764] [<c0077f5c>] (generic_handle_irq) from [<c0078220>] (__handle_domain_irq+0x6c/0xb4)
[    3.414456] [<c0078220>] (__handle_domain_irq) from [<c0008754>] (gic_handle_irq+0x34/0x6c)
[    3.422802] [<c0008754>] (gic_handle_irq) from [<c0027540>] (__irq_svc+0x40/0x74)
[    3.430274] Exception stack(0xc09c1df8 to 0xc09c1e40)
[    3.435321] 1de0:                                                       00000001 c0a27ec0
[    3.443491] 1e00: 00000000 00000000 c09c0028 0000001e 00000282 00000000 ee00c400 c0a239f8
[    3.451660] 1e20: c09c0000 c09c1ea4 c0a27ec0 c09c1e40 00200000 c003c7cc 20000113 ffffffff
[    3.459835] [<c0027540>] (__irq_svc) from [<c003c7cc>] (__do_softirq+0xbc/0x34c)
[    3.467229] [<c003c7cc>] (__do_softirq) from [<c003cd44>] (irq_exit+0xbc/0x104)
[    3.474536] [<c003cd44>] (irq_exit) from [<c0078224>] (__handle_domain_irq+0x70/0xb4)
[    3.482362] [<c0078224>] (__handle_domain_irq) from [<c0008754>] (gic_handle_x74)
[    3.498169] Exception stack(0xc09c1f10 to 0xc09c1f58)
[    3.503216] 1f00:                                     ee7ca310 00000000 00000ab4 c0035560
[    3.511386] 1f20: c09c0000 00000000 c0a23f84 c09c8474 c09c84bc c09c0000 c0688bf8 c09c1f64
[    3.519554] 1f40: c09c1f68 c09c1f58 c00235d8 c00235dc 60000113 ffffffff
[    3.526165] [<c0027540>] (__irq_svc) from [<c00235dc>] (arch_cpu_idle+0x48/0x4c)
[    3.533557] [<c00235dc>] (arch_cpu_idle) from [<c00701fc>] (cpu_startup_entry+0x13c/0x27c)
[    3.541816] [<c00701fc>] (cpu_startup_entry) from [<c067af1c>] (rest_init+0x94/0x98)
[    3.549557] [<c067af1c>] (rest_init) from [<c093dd38>] (start_kernel+0x3f0/0x3fc)
[    3.557036] [<c093dd38>] (start_kernel) from [<40008084>] (0x40008084)
[    3.563555] handlers:
[    3.565830] [<c03a1a80>] ahci_single_irq_intr threaded [<c03a223c>] ahci_thread_fn
[    3.573415] Disabling IRQ #88
[    3.576532] ata1: exception Emask 0x10 SAct 0x0 SErr 0x4050002 action 0xe frozen
[    3.583977] ata1: irq_stat 0x00400040, connection status changed
[    3.590006] ata1: SError: { RecovComm PHYRdyChg CommWake DevExch }
[    3.596209] ata1: hard resetting link
[...]

Not good. The culprit is a missing IRQF_ONESHOT flag, which addition
solves the problem entierly. The number of interrupts drops radically:

[Booting Debian Jessie to a prompt]
Before fix:
 88:       3562          0       GIC  88  ahci-sunxi
After fix:
 88:       1992          0       GIC  88  ahci-sunxi

Tested on a A20 board (ahci-sunxi).

Cc: Alexander Gordeev <agordeev@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-ide@vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
ahci_sunxi: Drop AHCI_HFLAG_NO_PMP flag

This is something which we inherited from the Allwinner android kernel sources,
and I've always wanted to test if this is really necessary.

So recently I've bought a sata port multiplexer, and I've given this a test
spin on both A10 and A20 devices, and it seems to work fine:

[    2.154456] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[    2.161092] ata1.15: Port Multiplier 1.2, 0x197b:0x0325 r0, 5 ports, feat 0x5/0xf
[    2.175511] ata1.00: hard resetting link
[    2.524929] ata1.00: SATA link up 3.0 Gbps (SStatus 123 SControl 320)
[    2.531430] ata1.01: hard resetting link
[    2.974465] ata1.01: link resume succeeded after 1 retries
[    3.094932] ata1.01: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[    3.101431] ata1.02: hard resetting link
[    4.174466] ata1.02: failed to resume link (SControl 0)
[    4.180065] ata1.02: SATA link down (SStatus 0 SControl 0)
(and the same for links 3 and 4)

Once the NO_PMP flag is removed it correctly sees the 2 disks which I've
attached, and I can mount and use them just fine, so lets drop the flag.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>