linux-ti33x-psp 3.2: make st7735fb DMA safe

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net> Signed-off-by: Denys Dmytriyenko <denys@ti.com>
2026-06-04 18:00:36 +00:00 · 2012-05-16 15:27:00 +02:00
parent a334f160ea
commit 0fbf85083f
2 changed files with 145 additions and 1 deletions
@@ -0,0 +1,143 @@
+From 783a66842e956b2eb9d7dc379848fbf79a370bc8 Mon Sep 17 00:00:00 2001
+From: Matt Porter <mporter@ti.com>
+Date: Wed, 28 Mar 2012 23:35:44 -0400
+Subject: [PATCH] st7735fb: Working WIP changes to make DMA safe and add
+ endian fix
+
+This removes the "from the stack" allocation of 1 byte buffers
+that was a temporary thing and isn't dma safe. Now vmallocs the
+user buffer to be deferred I/O safe and kmallocs a swapped
+shadow buffer to support the byte swabbing hack to fix userspace
+limitations.
+
+The buffer allocation and endian hack code needs some serious
+cleanup as on big endian systems if would fail miserably atm.
+However, the LE path works for the moment so people can do something
+with the driver.
+
+Signed-off-by: Matt Porter <mporter@ti.com>
+---
+ drivers/video/st7735fb.c |   49 ++++++++++++++++++++++++++++++----------------
+ include/video/st7735fb.h |    2 +
+ 2 files changed, 34 insertions(+), 17 deletions(-)
+
+diff --git a/drivers/video/st7735fb.c b/drivers/video/st7735fb.c
+index 500cc88..0931ca2 100644
+--- a/drivers/video/st7735fb.c
+++ b/drivers/video/st7735fb.c
+@@ -145,11 +145,9 @@ static struct fb_var_screeninfo st7735fb_var __devinitdata = {
+ 
+ static int st7735_write(struct st7735fb_par *par, u8 data)
+ {
+-	u8 txbuf[2]; /* allocation from stack must go */
+	par->buf[0] = data;
+ 
+-	txbuf[0] = data;
+-
+-	return spi_write(par->spi, &txbuf[0], 1);
+	return spi_write(par->spi, par->buf, 1);
+ }
+ 
+ static void st7735_write_data(struct st7735fb_par *par, u8 data)
+@@ -243,16 +241,17 @@ static void st7735_reset(struct st7735fb_par *par)
+ static void st7735fb_update_display(struct st7735fb_par *par)
+ {
+ 	int ret = 0;
+-	u8 *vmem = par->info->screen_base;
+-
+-	/*
+-		TODO:
+-		Allow a subset of pages to be passed in
+-		(for deferred I/O).  Check pages against
+-		pan display settings to see if they
+-		should be updated.
+-	*/
+-	/* For now, just write the full 40KiB on each update */
+	u16 *vmem;
+#ifdef __LITTLE_ENDIAN
+	int i;
+	u16 *vmem16 = (u16 *)par->info->screen_base;
+	vmem = par->ssbuf;
+
+	for (i=0; i<WIDTH*HEIGHT*BPP/8/2; i++)
+		vmem[i] = swab16(vmem16[i]);
+#else
+	vmem = (u16 *)par->info->screen_base;
+#endif
+ 
+ 	/* Set row/column data window */
+ 	st7735_set_addr_win(par, 0, 0, WIDTH-1, HEIGHT-1);
+@@ -261,7 +260,7 @@ static void st7735fb_update_display(struct st7735fb_par *par)
+ 	st7735_write_cmd(par, ST7735_RAMWR);
+ 
+ 	/* Blast framebuffer to ST7735 internal display RAM */
+-	ret = st7735_write_data_buf(par, vmem, WIDTH*HEIGHT*BPP/8);
+	ret = st7735_write_data_buf(par, (u8 *)vmem, WIDTH*HEIGHT*BPP/8);
+ 	if (ret < 0)
+ 		pr_err("%s: spi_write failed to update display buffer\n",
+ 			par->info->fix.id);
+@@ -369,7 +368,7 @@ static struct fb_ops st7735fb_ops = {
+ };
+ 
+ static struct fb_deferred_io st7735fb_defio = {
+-	.delay		= HZ,
+	.delay		= HZ/20,
+ 	.deferred_io	= st7735fb_deferred_io,
+ };
+ 
+@@ -395,7 +394,11 @@ static int __devinit st7735fb_probe (struct spi_device *spi)
+ 		return -EINVAL;
+ 	}
+ 
+-	vmem = vzalloc(vmem_size);
+#ifdef __LITTLE_ENDIAN
+	vmem = (u8 *)vmalloc(vmem_size);
+#else
+	vmem = (u8 *)kmalloc(vmem_size, GFP_KERNEL);
+#endif
+ 	if (!vmem)
+ 		return retval;
+ 
+@@ -431,6 +434,14 @@ static int __devinit st7735fb_probe (struct spi_device *spi)
+ 	par->spi = spi;
+ 	par->rst = pdata->rst_gpio;
+ 	par->dc = pdata->dc_gpio;
+	par->buf = kmalloc(1, GFP_KERNEL);
+
+#ifdef __LITTLE_ENDIAN
+	/* Allocated swapped shadow buffer */
+	par->ssbuf = kmalloc(vmem_size, GFP_KERNEL);
+	if (!par->ssbuf)
+		return retval;
+#endif
+ 
+ 	retval = register_framebuffer(info);
+ 	if (retval < 0)
+@@ -457,7 +468,11 @@ fbreg_fail:
+ 	framebuffer_release(info);
+ 
+ fballoc_fail:
+#ifdef __LITTLE_ENDIAN
+ 	vfree(vmem);
+#else
+	kfree(vmem);
+#endif
+ 
+ 	return retval;
+ }
+diff --git a/include/video/st7735fb.h b/include/video/st7735fb.h
+index 250f036..e99cd05 100644
+--- a/include/video/st7735fb.h
+++ b/include/video/st7735fb.h
+@@ -36,6 +36,8 @@ struct st7735fb_par {
+ 	struct fb_info *info;
+ 	int rst;
+ 	int dc;
+	u16 *ssbuf;
+	u8 *buf;
+ };
+ 
+ struct st7735fb_platform_data {
+-- 
+1.7.7.6
+
@@ -12,7 +12,7 @@ MULTI_CONFIG_BASE_SUFFIX = ""

 BRANCH = "v3.2-staging"
 SRCREV = "720e07b4c1f687b61b147b31c698cb6816d72f01"
-MACHINE_KERNEL_PR_append = "i+gitr${SRCREV}"
+MACHINE_KERNEL_PR_append = "j+gitr${SRCREV}"

 COMPATIBLE_MACHINE = "(ti33x)"

@@ -967,5 +967,6 @@ PATCHES_OVER_PSP = " \
 	file://beaglebone/0038-board-am335xevm.c-Beaglebone-expose-all-pwms-through.patch \
 	file://beaglebone/0039-ARM-OMAP-Mux-Fixed-debugfs-mux-output-always-reporti.patch \
 	file://beaglebone/0040-beaglebone-export-SPI2-as-spidev-when-no-capes-are-u.patch \
+    file://beaglebone/0043-st7735fb-Working-WIP-changes-to-make-DMA-safe-and-ad.patch \
 	file://beaglebone/0001-arm-boot-compressed-default-asm-arch-to-armv7-a.patch \
 "