fbdev: sh_mobile_hdmi: implement locking
The SH-Mobile HDMI driver runs in several contexts: ISR, delayed work-queue,
task context, when called from the sh_mobile_lcdc framebuffer driver. This
creates ample race possibilities. Even though most these races are purely
theoretical, it is better to close them. To trace fb_info validity we install a
notification callback in the HDMI driver, and the only way for it to get to
driver internal data is by using struct sh_mobile_lcdc_chan, therefore it had
to be extracted into a separate common header.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/drivers/video/sh_mobile_lcdcfb.c b/drivers/video/sh_mobile_lcdcfb.c
index ddd6c46..29d7ce7 100644
--- a/drivers/video/sh_mobile_lcdcfb.c
+++ b/drivers/video/sh_mobile_lcdcfb.c
@@ -12,7 +12,6 @@
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/mm.h>
-#include <linux/fb.h>
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/platform_device.h>
@@ -24,7 +23,8 @@
#include <video/sh_mobile_lcdc.h>
#include <asm/atomic.h>
-#define PALETTE_NR 16
+#include "sh_mobile_lcdcfb.h"
+
#define SIDE_B_OFFSET 0x1000
#define MIRROR_OFFSET 0x2000
@@ -53,12 +53,6 @@
};
#define NR_SHARED_REGS ARRAY_SIZE(lcdc_shared_regs)
-/* per-channel registers */
-enum { LDDCKPAT1R, LDDCKPAT2R, LDMT1R, LDMT2R, LDMT3R, LDDFR, LDSM1R,
- LDSM2R, LDSA1R, LDMLSR, LDHCNR, LDHSYNR, LDVLNR, LDVSYNR, LDPMR,
- LDHAJR,
- NR_CH_REGS };
-
static unsigned long lcdc_offs_mainlcd[NR_CH_REGS] = {
[LDDCKPAT1R] = 0x400,
[LDDCKPAT2R] = 0x404,
@@ -112,25 +106,6 @@
#define LDRCNTR_MRC 0x00000001
#define LDSR_MRS 0x00000100
-struct sh_mobile_lcdc_priv;
-struct sh_mobile_lcdc_chan {
- struct sh_mobile_lcdc_priv *lcdc;
- unsigned long *reg_offs;
- unsigned long ldmt1r_value;
- unsigned long enabled; /* ME and SE in LDCNT2R */
- struct sh_mobile_lcdc_chan_cfg cfg;
- u32 pseudo_palette[PALETTE_NR];
- unsigned long saved_ch_regs[NR_CH_REGS];
- struct fb_info *info;
- dma_addr_t dma_handle;
- struct fb_deferred_io defio;
- struct scatterlist *sglist;
- unsigned long frame_end;
- unsigned long pan_offset;
- wait_queue_head_t frame_end_wait;
- struct completion vsync_completion;
-};
-
struct sh_mobile_lcdc_priv {
void __iomem *base;
int irq;
@@ -589,8 +564,10 @@
continue;
board_cfg = &ch->cfg.board_cfg;
- if (board_cfg->display_on)
+ if (try_module_get(board_cfg->owner) && board_cfg->display_on) {
board_cfg->display_on(board_cfg->board_data, ch->info);
+ module_put(board_cfg->owner);
+ }
}
return 0;
@@ -622,8 +599,10 @@
}
board_cfg = &ch->cfg.board_cfg;
- if (board_cfg->display_off)
+ if (try_module_get(board_cfg->owner) && board_cfg->display_off) {
board_cfg->display_off(board_cfg->board_data);
+ module_put(board_cfg->owner);
+ }
}
/* stop the lcdc */
@@ -954,6 +933,7 @@
.runtime_resume = sh_mobile_lcdc_runtime_resume,
};
+/* locking: called with info->lock held */
static int sh_mobile_lcdc_notify(struct notifier_block *nb,
unsigned long action, void *data)
{
@@ -971,16 +951,20 @@
switch(action) {
case FB_EVENT_SUSPEND:
- if (board_cfg->display_off)
+ if (try_module_get(board_cfg->owner) && board_cfg->display_off) {
board_cfg->display_off(board_cfg->board_data);
+ module_put(board_cfg->owner);
+ }
pm_runtime_put(info->device);
break;
case FB_EVENT_RESUME:
var = &info->var;
/* HDMI must be enabled before LCDC configuration */
- if (board_cfg->display_on)
+ if (try_module_get(board_cfg->owner) && board_cfg->display_on) {
board_cfg->display_on(board_cfg->board_data, ch->info);
+ module_put(board_cfg->owner);
+ }
/* Check if the new display is not in our modelist */
if (ch->info->modelist.next &&