HID: picolcd: Add minimal palette required by fbcon on 8bpp

Add a minimal palette so fbcon does not try to dereference
a NULL point when fb is set to 8bpp.

fbcon stores pixels the other way around in bytes for 1bpp
than intially implemented, correct this.

Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 51 insertions, 11 deletions

diff --git a/drivers/hid/hid-picolcd.c b/drivers/hid/hid-picolcd.c
index 839a5ac0ad82..dc19501a786f 100644
--- a/drivers/hid/hid-picolcd.c
+++ b/drivers/hid/hid-picolcd.c
@@ -127,6 +127,26 @@ static const struct fb_var_screeninfo picolcdfb_var = {
         .height         = 26,
         .bits_per_pixel = 1,
         .grayscale      = 1,
+        .red            = {
+                .offset = 0,
+                .length = 1,
+                .msb_right = 0,
+        },
+        .green          = {
+                .offset = 0,
+                .length = 1,
+                .msb_right = 0,
+        },
+        .blue           = {
+                .offset = 0,
+                .length = 1,
+                .msb_right = 0,
+        },
+        .transp         = {
+                .offset = 0,
+                .length = 0,
+                .msb_right = 0,
+        },
 };
 #endif /* CONFIG_HID_PICOLCD_FB */
 
@@ -188,6 +208,7 @@ struct picolcd_data {
         /* Framebuffer stuff */
         u8 fb_update_rate;
         u8 fb_bpp;
+        u8 fb_force;
         u8 *fb_vbitmap;         /* local copy of what was sent to PicoLCD */
         u8 *fb_bitmap;          /* framebuffer */
         struct fb_info *fb_info;
@@ -346,7 +367,7 @@ static int picolcd_fb_update_tile(u8 *vbitmap, const u8 *bitmap, int bpp,
                         const u8 *bdata = bitmap + tile * 256 + chip * 8 + b * 32;
                         for (i = 0; i < 64; i++) {
                                 tdata[i] <<= 1;
-                                tdata[i] |= (bdata[i/8] >> (7 - i % 8)) & 0x01;
+                                tdata[i] |= (bdata[i/8] >> (i % 8)) & 0x01;
                         }
                 }
         } else if (bpp == 8) {
@@ -399,13 +420,10 @@ static int picolcd_fb_reset(struct picolcd_data *data, int clear)
 
         if (data->fb_bitmap) {
                 if (clear) {
-                        memset(data->fb_vbitmap, 0xff, PICOLCDFB_SIZE);
+                        memset(data->fb_vbitmap, 0, PICOLCDFB_SIZE);
                         memset(data->fb_bitmap, 0, PICOLCDFB_SIZE*data->fb_bpp);
-                } else {
-                        /* invert 1 byte in each tile to force resend */
-                        for (i = 0; i < PICOLCDFB_SIZE; i += 64)
-                                data->fb_vbitmap[i] = ~data->fb_vbitmap[i];
                 }
+                data->fb_force = 1;
         }
 
         /* schedule first output of framebuffer */
@@ -440,7 +458,8 @@ static void picolcd_fb_update(struct picolcd_data *data)
         for (chip = 0; chip < 4; chip++)
                 for (tile = 0; tile < 8; tile++)
                         if (picolcd_fb_update_tile(data->fb_vbitmap,
-                                        data->fb_bitmap, data->fb_bpp, chip, tile)) {
+                                        data->fb_bitmap, data->fb_bpp, chip, tile) ||
+                                data->fb_force) {
                                 n += 2;
                                 if (n >= HID_OUTPUT_FIFO_SIZE / 2) {
                                         usbhid_wait_io(data->hdev);
@@ -448,6 +467,7 @@ static void picolcd_fb_update(struct picolcd_data *data)
                                 }
                                 picolcd_fb_send_tile(data->hdev, chip, tile);
                         }
+        data->fb_force = false;
         if (n)
                 usbhid_wait_io(data->hdev);
 }
@@ -526,10 +546,17 @@ static int picolcd_fb_check_var(struct fb_var_screeninfo *var, struct fb_info *i
         /* only allow 1/8 bit depth (8-bit is grayscale) */
         *var = picolcdfb_var;
         var->activate = activate;
-        if (bpp >= 8)
+        if (bpp >= 8) {
                 var->bits_per_pixel = 8;
-        else
+                var->red.length     = 8;
+                var->green.length   = 8;
+                var->blue.length    = 8;
+        } else {
                 var->bits_per_pixel = 1;
+                var->red.length     = 1;
+                var->green.length   = 1;
+                var->blue.length    = 1;
+        }
         return 0;
 }
 
@@ -660,9 +687,10 @@ static int picolcd_init_framebuffer(struct picolcd_data *data)
 {
         struct device *dev = &data->hdev->dev;
         struct fb_info *info = NULL;
-        int error = -ENOMEM;
+        int i, error = -ENOMEM;
         u8 *fb_vbitmap = NULL;
         u8 *fb_bitmap  = NULL;
+        u32 *palette;
 
         fb_bitmap = vmalloc(PICOLCDFB_SIZE*picolcdfb_var.bits_per_pixel);
         if (fb_bitmap == NULL) {
@@ -678,12 +706,23 @@ static int picolcd_init_framebuffer(struct picolcd_data *data)
 
         data->fb_update_rate = PICOLCDFB_UPDATE_RATE_DEFAULT;
         data->fb_defio = picolcd_fb_defio;
-        info = framebuffer_alloc(0, dev);
+        /* The extra memory is:
+         * - struct picolcd_fb_cleanup_item
+         * - u32 for ref_count
+         * - 256*u32 for pseudo_palette
+         */
+        info = framebuffer_alloc(257 * sizeof(u32), dev);
         if (info == NULL) {
                 dev_err(dev, "failed to allocate a framebuffer\n");
                 goto err_nomem;
         }
 
+        palette  = info->par;
+        *palette = 1;
+        palette++;
+        for (i = 0; i < 256; i++)
+                palette[i] = i > 0 && i < 16 ? 0xff : 0;
+        info->pseudo_palette = palette;
         info->fbdefio = &data->fb_defio;
         info->screen_base = (char __force __iomem *)fb_bitmap;
         info->fbops = &picolcdfb_ops;
@@ -715,6 +754,7 @@ static int picolcd_init_framebuffer(struct picolcd_data *data)
                 goto err_sysfs;
         }
         /* schedule first output of framebuffer */
+        data->fb_force = 1;
         schedule_delayed_work(&info->deferred_work, 0);
         return 0;