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From:   Guenter Roeck <linux@roeck-us.net>
To:     Ley Foon Tan <lftan@altera.com>
Cc:     nios2-dev@lists.rocketboards.org, linux-kernel@vger.kernel.org,
        Guenter Roeck <linux@roeck-us.net>,
        Christoph Hellwig <hch@lst.de>
Subject: [PATCH] nios2: Fix ioremap
Date:   Wed,  4 Dec 2019 18:41:00 -0800
Message-Id: <20191205024100.1066-1-linux@roeck-us.net>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Commit 5ace77e0b41a ("nios2: remove __ioremap") removed the following code,
with the argument that cacheflag is always 0 and the expression would
therefore always be false.

	if (IS_MAPPABLE_UNCACHEABLE(phys_addr) &&
	    IS_MAPPABLE_UNCACHEABLE(last_addr) &&
	    !(cacheflag & _PAGE_CACHED))
		return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr);

This did not take the "!" in the expression into account. Result is that
nios2 images no longer boot. Restoring the removed code fixes the problem.

Fixes: 5ace77e0b41a ("nios2: remove __ioremap")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 arch/nios2/mm/ioremap.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/nios2/mm/ioremap.c b/arch/nios2/mm/ioremap.c
index b56af759dcdf..819bdfcc2e71 100644
--- a/arch/nios2/mm/ioremap.c
+++ b/arch/nios2/mm/ioremap.c
@@ -138,6 +138,14 @@ void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
 				return NULL;
 	}
 
+	/*
+	 * Map uncached objects in the low part of address space to
+	 * CONFIG_NIOS2_IO_REGION_BASE
+	 */
+	if (IS_MAPPABLE_UNCACHEABLE(phys_addr) &&
+	    IS_MAPPABLE_UNCACHEABLE(last_addr))
+		return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr);
+
 	/* Mappings have to be page-aligned */
 	offset = phys_addr & ~PAGE_MASK;
 	phys_addr &= PAGE_MASK;
-- 
2.17.1