linux-kernel - [PATCH v3 6/8] video: xilinxfb: Add support for little endian accesses

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Date:	Fri, 31 May 2013 14:55:36 +0200
From:	Michal Simek <michal.simek@...inx.com>
To:	linux-kernel@...r.kernel.org
Cc:	Michal Simek <monstr@...str.eu>,
	Michal Simek <michal.simek@...inx.com>,
	Arnd Bergmann <arnd@...db.de>, Timur Tabi <timur@...i.org>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Tomi Valkeinen <tomi.valkeinen@...com>,
	linux-fbdev@...r.kernel.org
Subject: [PATCH v3 6/8] video: xilinxfb: Add support for little endian accesses

Dynamically detect endianess on IP and use
ioread/iowrite functions instead of powerpc and microblaze
specific out_be32.

Signed-off-by: Michal Simek <michal.simek@...inx.com>
---
Changes in v3:
- New patch in this patchset based on discussions

Changes in v2: None

 drivers/video/xilinxfb.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/video/xilinxfb.c b/drivers/video/xilinxfb.c
index bd3b85d..f3d4a69 100644
--- a/drivers/video/xilinxfb.c
+++ b/drivers/video/xilinxfb.c
@@ -117,6 +117,7 @@ static struct fb_var_screeninfo xilinx_fb_var = {


 #define BUS_ACCESS_FLAG		0x1 /* 1 = BUS, 0 = DCR */
+#define LITTLE_ENDIAN_ACCESS	0x2 /* LITTLE ENDIAN IO functions */

 struct xilinxfb_drvdata {

@@ -153,14 +154,33 @@ struct xilinxfb_drvdata {
 static void xilinx_fb_out32(struct xilinxfb_drvdata *drvdata, u32 offset,
 				u32 val)
 {
-	if (drvdata->flags & BUS_ACCESS_FLAG)
-		out_be32(drvdata->regs + (offset << 2), val);
+	if (drvdata->flags & BUS_ACCESS_FLAG) {
+		if (drvdata->flags & LITTLE_ENDIAN_ACCESS)
+			iowrite32(val, drvdata->regs + (offset << 2));
+		else
+			iowrite32be(val, drvdata->regs + (offset << 2));
+	}
 #ifdef CONFIG_PPC_DCR
 	else
 		dcr_write(drvdata->dcr_host, offset, val);
 #endif
 }

+static u32 xilinx_fb_in32(struct xilinxfb_drvdata *drvdata, u32 offset)
+{
+	if (drvdata->flags & BUS_ACCESS_FLAG) {
+		if (drvdata->flags & LITTLE_ENDIAN_ACCESS)
+			return ioread32(drvdata->regs + (offset << 2));
+		else
+			return ioread32be(drvdata->regs + (offset << 2));
+	}
+#ifdef CONFIG_PPC_DCR
+	else
+		return dcr_read(drvdata->dcr_host, offset);
+#endif
+	return 0;
+}
+
 static int
 xilinx_fb_setcolreg(unsigned regno, unsigned red, unsigned green, unsigned blue,
 	unsigned transp, struct fb_info *fbi)
@@ -271,6 +291,12 @@ static int xilinxfb_assign(struct platform_device *pdev,

 	/* Tell the hardware where the frame buffer is */
 	xilinx_fb_out32(drvdata, REG_FB_ADDR, drvdata->fb_phys);
+	rc = xilinx_fb_in32(drvdata, REG_FB_ADDR);
+	/* Endianess detection */
+	if (rc != drvdata->fb_phys) {
+		drvdata->flags |= LITTLE_ENDIAN_ACCESS;
+		xilinx_fb_out32(drvdata, REG_FB_ADDR, drvdata->fb_phys);
+	}

 	/* Turn on the display */
 	drvdata->reg_ctrl_default = REG_CTRL_ENABLE;
--
1.8.2.3


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