fbdev: hecuba Framebuffer Driver

This patch implements support for the E-Ink/hecuba display device.  It uses
deferred IO support.

[akpm@linux-foundation.org: linker section fixes]
Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 495 insertions, 0 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 61c0a03d33f2..0aeab4e725a4 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -557,6 +557,20 @@ config FB_IMAC
         help
           This is the frame buffer device driver for the Intel-based Macintosh
 
+config FB_HECUBA
+       tristate "Hecuba board support"
+       depends on FB && X86 && MMU
+       select FB_CFB_FILLRECT
+       select FB_CFB_COPYAREA
+       select FB_CFB_IMAGEBLIT
+       select FB_DEFERRED_IO
+       help
+         This enables support for the Hecuba board. This driver was tested
+         with an E-Ink 800x600 display and x86 SBCs through a 16 bit GPIO
+         interface (8 bit data, 4 bit control). If you anticpate using
+         this driver, say Y or M; otherwise say N. You must specify the
+         GPIO IO address to be used for setting control and data.
+
 config FB_HGA
         tristate "Hercules mono graphics support"
         depends on FB && X86
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index deb5fa55f783..49d01eb48c7b 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_FB_ACORN)            += acornfb.o
 obj-$(CONFIG_FB_ATARI)            += atafb.o c2p.o atafb_mfb.o \
                                      atafb_iplan2p2.o atafb_iplan2p4.o atafb_iplan2p8.o
 obj-$(CONFIG_FB_MAC)              += macfb.o
+obj-$(CONFIG_FB_HECUBA)           += hecubafb.o
 obj-$(CONFIG_FB_HGA)              += hgafb.o
 obj-$(CONFIG_FB_XVR500)           += sunxvr500.o
 obj-$(CONFIG_FB_XVR2500)          += sunxvr2500.o
diff --git a/drivers/video/hecubafb.c b/drivers/video/hecubafb.c
new file mode 100644
index 000000000000..396dc277ab51
--- /dev/null
+++ b/drivers/video/hecubafb.c
@@ -0,0 +1,480 @@
+/*
+ * linux/drivers/video/hecubafb.c -- FB driver for Hecuba controller
+ *
+ * Copyright (C) 2006, Jaya Kumar
+ * This work was sponsored by CIS(M) Sdn Bhd
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of this archive for
+ * more details.
+ *
+ * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
+ * This work was possible because of apollo display code from E-Ink's website
+ * http://support.eink.com/community
+ * All information used to write this code is from public material made
+ * available by E-Ink on its support site. Some commands such as 0xA4
+ * were found by looping through cmd=0x00 thru 0xFF and supplying random
+ * values. There are other commands that the display is capable of,
+ * beyond the 5 used here but they are more complex.
+ *
+ * This driver is written to be used with the Hecuba display controller
+ * board, and tested with the EInk 800x600 display in 1 bit mode.
+ * The interface between Hecuba and the host is TTL based GPIO. The
+ * GPIO requirements are 8 writable data lines and 6 lines for control.
+ * Only 4 of the controls are actually used here but 6 for future use.
+ * The driver requires the IO addresses for data and control GPIO at
+ * load time. It is also possible to use this display with a standard
+ * PC parallel port.
+ *
+ * General notes:
+ * - User must set hecubafb_enable=1 to enable it
+ * - User must set dio_addr=0xIOADDR cio_addr=0xIOADDR c2io_addr=0xIOADDR
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/fb.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/list.h>
+#include <asm/uaccess.h>
+
+/* Apollo controller specific defines */
+#define APOLLO_START_NEW_IMG    0xA0
+#define APOLLO_STOP_IMG_DATA    0xA1
+#define APOLLO_DISPLAY_IMG      0xA2
+#define APOLLO_ERASE_DISPLAY    0xA3
+#define APOLLO_INIT_DISPLAY     0xA4
+
+/* Hecuba interface specific defines */
+/* WUP is inverted, CD is inverted, DS is inverted */
+#define HCB_NWUP_BIT    0x01
+#define HCB_NDS_BIT     0x02
+#define HCB_RW_BIT      0x04
+#define HCB_NCD_BIT     0x08
+#define HCB_ACK_BIT     0x80
+
+/* Display specific information */
+#define DPY_W 600
+#define DPY_H 800
+
+struct hecubafb_par {
+        unsigned long dio_addr;
+        unsigned long cio_addr;
+        unsigned long c2io_addr;
+        unsigned char ctl;
+        struct fb_info *info;
+        unsigned int irq;
+};
+
+static struct fb_fix_screeninfo hecubafb_fix __devinitdata = {
+        .id =           "hecubafb",
+        .type =         FB_TYPE_PACKED_PIXELS,
+        .visual =       FB_VISUAL_MONO01,
+        .xpanstep =     0,
+        .ypanstep =     0,
+        .ywrapstep =    0,
+        .accel =        FB_ACCEL_NONE,
+};
+
+static struct fb_var_screeninfo hecubafb_var __devinitdata = {
+        .xres           = DPY_W,
+        .yres           = DPY_H,
+        .xres_virtual   = DPY_W,
+        .yres_virtual   = DPY_H,
+        .bits_per_pixel = 1,
+        .nonstd         = 1,
+};
+
+static unsigned long dio_addr;
+static unsigned long cio_addr;
+static unsigned long c2io_addr;
+static unsigned long splashval;
+static unsigned int nosplash;
+static unsigned int hecubafb_enable;
+static unsigned int irq;
+
+static DECLARE_WAIT_QUEUE_HEAD(hecubafb_waitq);
+
+static void hcb_set_ctl(struct hecubafb_par *par)
+{
+        outb(par->ctl, par->cio_addr);
+}
+
+static unsigned char hcb_get_ctl(struct hecubafb_par *par)
+{
+        return inb(par->c2io_addr);
+}
+
+static void hcb_set_data(struct hecubafb_par *par, unsigned char value)
+{
+        outb(value, par->dio_addr);
+}
+
+static int __devinit apollo_init_control(struct hecubafb_par *par)
+{
+        unsigned char ctl;
+        /* for init, we want the following setup to be set:
+        WUP = lo
+        ACK = hi
+        DS = hi
+        RW = hi
+        CD = lo
+        */
+
+        /* write WUP to lo, DS to hi, RW to hi, CD to lo */
+        par->ctl = HCB_NWUP_BIT | HCB_RW_BIT | HCB_NCD_BIT ;
+        par->ctl &= ~HCB_NDS_BIT;
+        hcb_set_ctl(par);
+
+        /* check ACK is not lo */
+        ctl = hcb_get_ctl(par);
+        if ((ctl & HCB_ACK_BIT)) {
+                printk(KERN_ERR "Fail because ACK is already low\n");
+                return -ENXIO;
+        }
+
+        return 0;
+}
+
+void hcb_wait_for_ack(struct hecubafb_par *par)
+{
+
+        int timeout;
+        unsigned char ctl;
+
+        timeout=500;
+        do {
+                ctl = hcb_get_ctl(par);
+                if ((ctl & HCB_ACK_BIT))
+                        return;
+                udelay(1);
+        } while (timeout--);
+        printk(KERN_ERR "timed out waiting for ack\n");
+}
+
+void hcb_wait_for_ack_clear(struct hecubafb_par *par)
+{
+
+        int timeout;
+        unsigned char ctl;
+
+        timeout=500;
+        do {
+                ctl = hcb_get_ctl(par);
+                if (!(ctl & HCB_ACK_BIT))
+                        return;
+                udelay(1);
+        } while (timeout--);
+        printk(KERN_ERR "timed out waiting for clear\n");
+}
+
+void apollo_send_data(struct hecubafb_par *par, unsigned char data)
+{
+        /* set data */
+        hcb_set_data(par, data);
+
+        /* set DS low */
+        par->ctl |= HCB_NDS_BIT;
+        hcb_set_ctl(par);
+
+        hcb_wait_for_ack(par);
+
+        /* set DS hi */
+        par->ctl &= ~(HCB_NDS_BIT);
+        hcb_set_ctl(par);
+
+        hcb_wait_for_ack_clear(par);
+}
+
+void apollo_send_command(struct hecubafb_par *par, unsigned char data)
+{
+        /* command so set CD to high */
+        par->ctl &= ~(HCB_NCD_BIT);
+        hcb_set_ctl(par);
+
+        /* actually strobe with command */
+        apollo_send_data(par, data);
+
+        /* clear CD back to low */
+        par->ctl |= (HCB_NCD_BIT);
+        hcb_set_ctl(par);
+}
+
+/* main hecubafb functions */
+
+static void hecubafb_dpy_update(struct hecubafb_par *par)
+{
+        int i;
+        unsigned char *buf = par->info->screen_base;
+
+        apollo_send_command(par, 0xA0);
+
+        for (i=0; i < (DPY_W*DPY_H/8); i++) {
+                apollo_send_data(par, *(buf++));
+        }
+
+        apollo_send_command(par, 0xA1);
+        apollo_send_command(par, 0xA2);
+}
+
+/* this is called back from the deferred io workqueue */
+static void hecubafb_dpy_deferred_io(struct fb_info *info,
+                                struct list_head *pagelist)
+{
+        hecubafb_dpy_update(info->par);
+}
+
+static void hecubafb_fillrect(struct fb_info *info,
+                                   const struct fb_fillrect *rect)
+{
+        struct hecubafb_par *par = info->par;
+
+        cfb_fillrect(info, rect);
+
+        hecubafb_dpy_update(par);
+}
+
+static void hecubafb_copyarea(struct fb_info *info,
+                                   const struct fb_copyarea *area)
+{
+        struct hecubafb_par *par = info->par;
+
+        cfb_copyarea(info, area);
+
+        hecubafb_dpy_update(par);
+}
+
+static void hecubafb_imageblit(struct fb_info *info,
+                                const struct fb_image *image)
+{
+        struct hecubafb_par *par = info->par;
+
+        cfb_imageblit(info, image);
+
+        hecubafb_dpy_update(par);
+}
+
+/*
+ * this is the slow path from userspace. they can seek and write to
+ * the fb. it's inefficient to do anything less than a full screen draw
+ */
+static ssize_t hecubafb_write(struct file *file, const char __user *buf,
+                                size_t count, loff_t *ppos)
+{
+        struct inode *inode;
+        int fbidx;
+        struct fb_info *info;
+        unsigned long p;
+        int err=-EINVAL;
+        struct hecubafb_par *par;
+        unsigned int xres;
+        unsigned int fbmemlength;
+
+        p = *ppos;
+        inode = file->f_dentry->d_inode;
+        fbidx = iminor(inode);
+        info = registered_fb[fbidx];
+
+        if (!info || !info->screen_base)
+                return -ENODEV;
+
+        par = info->par;
+        xres = info->var.xres;
+        fbmemlength = (xres * info->var.yres)/8;
+
+        if (p > fbmemlength)
+                return -ENOSPC;
+
+        err = 0;
+        if ((count + p) > fbmemlength) {
+                count = fbmemlength - p;
+                err = -ENOSPC;
+        }
+
+        if (count) {
+                char *base_addr;
+
+                base_addr = info->screen_base;
+                count -= copy_from_user(base_addr + p, buf, count);
+                *ppos += count;
+                err = -EFAULT;
+        }
+
+        hecubafb_dpy_update(par);
+
+        if (count)
+                return count;
+
+        return err;
+}
+
+static struct fb_ops hecubafb_ops = {
+        .owner          = THIS_MODULE,
+        .fb_write       = hecubafb_write,
+        .fb_fillrect    = hecubafb_fillrect,
+        .fb_copyarea    = hecubafb_copyarea,
+        .fb_imageblit   = hecubafb_imageblit,
+};
+
+static struct fb_deferred_io hecubafb_defio = {
+        .delay          = HZ,
+        .deferred_io    = hecubafb_dpy_deferred_io,
+};
+
+static int __devinit hecubafb_probe(struct platform_device *dev)
+{
+        struct fb_info *info;
+        int retval = -ENOMEM;
+        int videomemorysize;
+        unsigned char *videomemory;
+        struct hecubafb_par *par;
+
+        videomemorysize = (DPY_W*DPY_H)/8;
+
+        if (!(videomemory = vmalloc(videomemorysize)))
+                return retval;
+
+        memset(videomemory, 0, videomemorysize);
+
+        info = framebuffer_alloc(sizeof(struct hecubafb_par), &dev->dev);
+        if (!info)
+                goto err;
+
+        info->screen_base = (char __iomem *) videomemory;
+        info->fbops = &hecubafb_ops;
+
+        info->var = hecubafb_var;
+        info->fix = hecubafb_fix;
+        info->fix.smem_len = videomemorysize;
+        par = info->par;
+        par->info = info;
+
+        if (!dio_addr || !cio_addr || !c2io_addr) {
+                printk(KERN_WARNING "no IO addresses supplied\n");
+                goto err1;
+        }
+        par->dio_addr = dio_addr;
+        par->cio_addr = cio_addr;
+        par->c2io_addr = c2io_addr;
+        info->flags = FBINFO_FLAG_DEFAULT;
+
+        info->fbdefio = &hecubafb_defio;
+        fb_deferred_io_init(info);
+
+        retval = register_framebuffer(info);
+        if (retval < 0)
+                goto err1;
+        platform_set_drvdata(dev, info);
+
+        printk(KERN_INFO
+               "fb%d: Hecuba frame buffer device, using %dK of video memory\n",
+               info->node, videomemorysize >> 10);
+
+        /* this inits the dpy */
+        apollo_init_control(par);
+
+        apollo_send_command(par, APOLLO_INIT_DISPLAY);
+        apollo_send_data(par, 0x81);
+
+        /* have to wait while display resets */
+        udelay(1000);
+
+        /* if we were told to splash the screen, we just clear it */
+        if (!nosplash) {
+                apollo_send_command(par, APOLLO_ERASE_DISPLAY);
+                apollo_send_data(par, splashval);
+        }
+
+        return 0;
+err1:
+        framebuffer_release(info);
+err:
+        vfree(videomemory);
+        return retval;
+}
+
+static int __devexit hecubafb_remove(struct platform_device *dev)
+{
+        struct fb_info *info = platform_get_drvdata(dev);
+
+        if (info) {
+                fb_deferred_io_cleanup(info);
+                unregister_framebuffer(info);
+                vfree(info->screen_base);
+                framebuffer_release(info);
+        }
+        return 0;
+}
+
+static struct platform_driver hecubafb_driver = {
+        .probe  = hecubafb_probe,
+        .remove = hecubafb_remove,
+        .driver = {
+                .name   = "hecubafb",
+        },
+};
+
+static struct platform_device *hecubafb_device;
+
+static int __init hecubafb_init(void)
+{
+        int ret;
+
+        if (!hecubafb_enable) {
+                printk(KERN_ERR "Use hecubafb_enable to enable the device\n");
+                return -ENXIO;
+        }
+
+        ret = platform_driver_register(&hecubafb_driver);
+        if (!ret) {
+                hecubafb_device = platform_device_alloc("hecubafb", 0);
+                if (hecubafb_device)
+                        ret = platform_device_add(hecubafb_device);
+                else
+                        ret = -ENOMEM;
+
+                if (ret) {
+                        platform_device_put(hecubafb_device);
+                        platform_driver_unregister(&hecubafb_driver);
+                }
+        }
+        return ret;
+
+}
+
+static void __exit hecubafb_exit(void)
+{
+        platform_device_unregister(hecubafb_device);
+        platform_driver_unregister(&hecubafb_driver);
+}
+
+module_param(nosplash, uint, 0);
+MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
+module_param(hecubafb_enable, uint, 0);
+MODULE_PARM_DESC(hecubafb_enable, "Enable communication with Hecuba board");
+module_param(dio_addr, ulong, 0);
+MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
+module_param(cio_addr, ulong, 0);
+MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
+module_param(c2io_addr, ulong, 0);
+MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
+module_param(splashval, ulong, 0);
+MODULE_PARM_DESC(splashval, "Splash pattern: 0x00 is black, 0x01 is white");
+module_param(irq, uint, 0);
+MODULE_PARM_DESC(irq, "IRQ for the Hecuba board");
+
+module_init(hecubafb_init);
+module_exit(hecubafb_exit);
+
+MODULE_DESCRIPTION("fbdev driver for Hecuba board");
+MODULE_AUTHOR("Jaya Kumar");
+MODULE_LICENSE("GPL");