From ab79b0d5e099b0b1b5dff180a17d6f5836b84423 Mon Sep 17 00:00:00 2001
From: Sebastian Sumpf <sebastian.sumpf@genode-labs.com>
Date: Thu, 12 Nov 2015 15:00:39 +0100
Subject: [PATCH] ahci: Reset port before access

Also throw error if wakup from power safe mode failes.

Fix #1776
---
 repos/os/src/drivers/ahci/ahci.cc | 24 +++++++++++++++++++-----
 repos/os/src/drivers/ahci/ahci.h  | 17 ++++++++++++++---
 2 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/repos/os/src/drivers/ahci/ahci.cc b/repos/os/src/drivers/ahci/ahci.cc
index 5b6d40a5d..32e2fe5ab 100644
--- a/repos/os/src/drivers/ahci/ahci.cc
+++ b/repos/os/src/drivers/ahci/ahci.cc
@@ -71,6 +71,11 @@ struct Ahci
 		return sig == ATAPI_SIG_QEMU || sig == ATAPI_SIG;
 	}
 
+	bool is_ata(unsigned sig)
+	{
+		return sig == ATA_SIG;
+	}
+
 	/**
 	 * Forward IRQs to ports
 	 */
@@ -121,12 +126,21 @@ struct Ahci
 				continue;
 
 			Port port(hba, platform_hba, i);
-			bool enabled = port.enable();
-			unsigned sig = port.read<Port::Sig>();
 
-			PINF("\t\t#%u: %s", i, enabled ?
-			                       (is_atapi(sig) ? "ATAPI" : "ATA") :
-			                       "off");
+			/* check for ATA/ATAPI devices */
+			unsigned sig = port.read<Port::Sig>();
+			if (!is_atapi(sig) && !is_ata(sig)) {
+				PINF("\t\t#%u: off", i);
+				continue;
+			}
+
+			port.reset();
+
+			bool enabled = false;
+			try { enabled = port.enable(); }
+			catch (Port::Not_ready) { PERR("Could not enable port %u", i); }
+
+			PINF("\t\t#%u: %s", i, is_atapi(sig) ? "ATAPI" : "ATA");
 
 			if (!enabled)
 				continue;
diff --git a/repos/os/src/drivers/ahci/ahci.h b/repos/os/src/drivers/ahci/ahci.h
index 15b019e79..b63fc0ace 100644
--- a/repos/os/src/drivers/ahci/ahci.h
+++ b/repos/os/src/drivers/ahci/ahci.h
@@ -16,6 +16,7 @@
 
 #include <block/component.h>
 #include <os/attached_mmio.h>
+#include <util/retry.h>
 #include <util/volatile_object.h>
 
 static bool constexpr verbose = false;
@@ -389,6 +390,9 @@ struct Command_table
  */
 struct Port : Genode::Mmio
 {
+	struct Not_ready : Genode::Exception { };
+
+
 	Hba           &hba;
 	Platform::Hba &platform_hba;
 	unsigned       cmd_slots = hba.command_slots();
@@ -639,9 +643,16 @@ struct Port : Genode::Mmio
 			/* try to wake up device */
 			write<Cmd::Icc>(Ssts::Ipm::ACTIVE);
 
-			while ((Ssts::Dec::get(status) != Ssts::Dec::ESTABLISHED) ||
-			      !(Ssts::Ipm::get(status) &  Ssts::Ipm::ACTIVE))
-				status = read<Ssts>();
+			Genode::retry<Not_ready>(
+				[&] {
+							if ((Ssts::Dec::get(status) != Ssts::Dec::ESTABLISHED) ||
+							    !(Ssts::Ipm::get(status) &  Ssts::Ipm::ACTIVE))
+								throw Not_ready();
+				},
+				[&] {
+					hba.delayer().usleep(1000);
+					status = read<Ssts>();
+				}, 10);
 		}
 
 		return ((Ssts::Dec::get(status) == Ssts::Dec::ESTABLISHED) &&