fbdev: defio and Metronomefb

Implement support for the E-Ink Metronome controller.  It provides an mmapable
interface to the controller using defio support.  It was tested with a gumstix
pxa255 with Vizplex media using Xfbdev and various X clients such as xeyes,
xpdf, xloadimage.

This patch also fixes the following bug: Defio would cause a hang on write
access to the framebuffer as the page fault would be called ad-infinitum.  It
fixes fb_defio by setting the mapping to be used by page_mkclean.

Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 1034 insertions, 2 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index e0b0580705e4..1bd5fb30237d 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -1893,6 +1893,20 @@ config FB_XILINX
           framebuffer. ML300 carries a 640*480 LCD display on the board,
           ML403 uses a standard DB15 VGA connector.
 
+config FB_METRONOME
+       tristate "Metronome display controller support"
+       depends on FB && ARCH_PXA && MMU
+       select FB_SYS_FILLRECT
+       select FB_SYS_COPYAREA
+       select FB_SYS_IMAGEBLIT
+       select FB_SYS_FOPS
+       select FB_DEFERRED_IO
+       help
+         This enables support for the Metronome display controller. Tested
+         with an E-Ink 800x600 display and Gumstix Connex through an AMLCD
+         interface. Please read <file:Documentation/fb/metronomefb.txt>
+         for more information.
+
 config FB_VIRTUAL
         tristate "Virtual Frame Buffer support (ONLY FOR TESTING!)"
         depends on FB
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 03371c789039..11c0e5e05f21 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -103,6 +103,7 @@ obj-$(CONFIG_FB_PMAG_AA)	  += pmag-aa-fb.o
 obj-$(CONFIG_FB_PMAG_BA)          += pmag-ba-fb.o
 obj-$(CONFIG_FB_PMAGB_B)          += pmagb-b-fb.o
 obj-$(CONFIG_FB_MAXINE)           += maxinefb.o
+obj-$(CONFIG_FB_METRONOME)        += metronomefb.o
 obj-$(CONFIG_FB_S1D13XXX)         += s1d13xxxfb.o
 obj-$(CONFIG_FB_IMX)              += imxfb.o
 obj-$(CONFIG_FB_S3C2410)          += s3c2410fb.o
diff --git a/drivers/video/fb_defio.c b/drivers/video/fb_defio.c
index 0f8cfb988c90..24843fdd5395 100644
--- a/drivers/video/fb_defio.c
+++ b/drivers/video/fb_defio.c
@@ -4,7 +4,7 @@
  *  Copyright (C) 2006 Jaya Kumar
  *
  * 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
+ * License. See the file COPYING in the main directory of this archive
  * for more details.
  */
 
@@ -31,7 +31,7 @@ static int fb_deferred_io_fault(struct vm_area_struct *vma,
         unsigned long offset;
         struct page *page;
         struct fb_info *info = vma->vm_private_data;
-        /* info->screen_base is in System RAM */
+        /* info->screen_base is virtual memory */
         void *screen_base = (void __force *) info->screen_base;
 
         offset = vmf->pgoff << PAGE_SHIFT;
@@ -43,6 +43,15 @@ static int fb_deferred_io_fault(struct vm_area_struct *vma,
                 return VM_FAULT_SIGBUS;
 
         get_page(page);
+
+        if (vma->vm_file)
+                page->mapping = vma->vm_file->f_mapping;
+        else
+                printk(KERN_ERR "no mapping available\n");
+
+        BUG_ON(!page->mapping);
+        page->index = vmf->pgoff;
+
         vmf->page = page;
         return 0;
 }
@@ -138,11 +147,20 @@ EXPORT_SYMBOL_GPL(fb_deferred_io_init);
 
 void fb_deferred_io_cleanup(struct fb_info *info)
 {
+        void *screen_base = (void __force *) info->screen_base;
         struct fb_deferred_io *fbdefio = info->fbdefio;
+        struct page *page;
+        int i;
 
         BUG_ON(!fbdefio);
         cancel_delayed_work(&info->deferred_work);
         flush_scheduled_work();
+
+        /* clear out the mapping that we setup */
+        for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
+                page = vmalloc_to_page(screen_base + i);
+                page->mapping = NULL;
+        }
 }
 EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
 
diff --git a/drivers/video/metronomefb.c b/drivers/video/metronomefb.c
new file mode 100644
index 000000000000..e9a89fd82757
--- /dev/null
+++ b/drivers/video/metronomefb.c
@@ -0,0 +1,999 @@
+/*
+ * linux/drivers/video/metronomefb.c -- FB driver for Metronome controller
+ *
+ * Copyright (C) 2008, Jaya Kumar
+ *
+ * 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 made possible by help and equipment support from E-Ink
+ * Corporation. http://support.eink.com/community
+ *
+ * This driver is written to be used with the Metronome display controller.
+ * It was tested with an E-Ink 800x600 Vizplex EPD on a Gumstix Connex board
+ * using the Lyre interface board.
+ *
+ * General notes:
+ * - User must set metronomefb_enable=1 to enable it.
+ * - See Documentation/fb/metronomefb.txt for how metronome works.
+ */
+#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 <linux/firmware.h>
+#include <linux/dma-mapping.h>
+#include <linux/uaccess.h>
+#include <linux/irq.h>
+
+#include <asm/arch/pxa-regs.h>
+#include <asm/unaligned.h>
+
+#define DEBUG 1
+#ifdef DEBUG
+#define DPRINTK(f, a...) printk(KERN_DEBUG "%s: " f, __func__ , ## a)
+#else
+#define DPRINTK(f, a...)
+#endif
+
+
+/* Display specific information */
+#define DPY_W 832
+#define DPY_H 622
+
+struct metromem_desc {
+        u32 mFDADR0;
+        u32 mFSADR0;
+        u32 mFIDR0;
+        u32 mLDCMD0;
+};
+
+struct metromem_cmd {
+        u16 opcode;
+        u16 args[((64-2)/2)];
+        u16 csum;
+};
+
+struct metronomefb_par {
+        unsigned char *metromem;
+        struct metromem_desc *metromem_desc;
+        struct metromem_cmd *metromem_cmd;
+        unsigned char *metromem_wfm;
+        unsigned char *metromem_img;
+        u16 *metromem_img_csum;
+        u16 *csum_table;
+        int metromemsize;
+        dma_addr_t metromem_dma;
+        dma_addr_t metromem_desc_dma;
+        struct fb_info *info;
+        wait_queue_head_t waitq;
+        u8 frame_count;
+};
+
+/* frame differs from image. frame includes non-visible pixels */
+struct epd_frame {
+        int fw; /* frame width */
+        int fh; /* frame height */
+};
+
+static struct epd_frame epd_frame_table[] = {
+        {
+        .fw = 832,
+        .fh = 622
+        },
+};
+
+static struct fb_fix_screeninfo metronomefb_fix __devinitdata = {
+        .id =           "metronomefb",
+        .type =         FB_TYPE_PACKED_PIXELS,
+        .visual =       FB_VISUAL_STATIC_PSEUDOCOLOR,
+        .xpanstep =     0,
+        .ypanstep =     0,
+        .ywrapstep =    0,
+        .line_length =  DPY_W,
+        .accel =        FB_ACCEL_NONE,
+};
+
+static struct fb_var_screeninfo metronomefb_var __devinitdata = {
+        .xres           = DPY_W,
+        .yres           = DPY_H,
+        .xres_virtual   = DPY_W,
+        .yres_virtual   = DPY_H,
+        .bits_per_pixel = 8,
+        .grayscale      = 1,
+        .nonstd         = 1,
+        .red =          { 4, 3, 0 },
+        .green =        { 0, 0, 0 },
+        .blue =         { 0, 0, 0 },
+        .transp =       { 0, 0, 0 },
+};
+
+static unsigned int metronomefb_enable;
+
+struct waveform_hdr {
+        u8 stuff[32];
+
+        u8 wmta[3];
+        u8 fvsn;
+
+        u8 luts;
+        u8 mc;
+        u8 trc;
+        u8 stuff3;
+
+        u8 endb;
+        u8 swtb;
+        u8 stuff2a[2];
+
+        u8 stuff2b[3];
+        u8 wfm_cs;
+} __attribute__ ((packed));
+
+/* main metronomefb functions */
+static u8 calc_cksum(int start, int end, u8 *mem)
+{
+        u8 tmp = 0;
+        int i;
+
+        for (i = start; i < end; i++)
+                tmp += mem[i];
+
+        return tmp;
+}
+
+static u16 calc_img_cksum(u16 *start, int length)
+{
+        u16 tmp = 0;
+
+        while (length--)
+                tmp += *start++;
+
+        return tmp;
+}
+
+/* here we decode the incoming waveform file and populate metromem */
+#define EXP_WFORM_SIZE 47001
+static int load_waveform(u8 *mem, size_t size, u8 *metromem, int m, int t,
+                                u8 *frame_count)
+{
+        int tta;
+        int wmta;
+        int trn = 0;
+        int i;
+        unsigned char v;
+        u8 cksum;
+        int cksum_idx;
+        int wfm_idx, owfm_idx;
+        int mem_idx = 0;
+        struct waveform_hdr *wfm_hdr;
+
+        if (size != EXP_WFORM_SIZE) {
+                printk(KERN_ERR "Error: unexpected size %d != %d\n", size,
+                                        EXP_WFORM_SIZE);
+                return -EINVAL;
+        }
+
+        wfm_hdr = (struct waveform_hdr *) mem;
+
+        if (wfm_hdr->fvsn != 1) {
+                printk(KERN_ERR "Error: bad fvsn %x\n", wfm_hdr->fvsn);
+                return -EINVAL;
+        }
+        if (wfm_hdr->luts != 0) {
+                printk(KERN_ERR "Error: bad luts %x\n", wfm_hdr->luts);
+                return -EINVAL;
+        }
+        cksum = calc_cksum(32, 47, mem);
+        if (cksum != wfm_hdr->wfm_cs) {
+                printk(KERN_ERR "Error: bad cksum %x != %x\n", cksum,
+                                        wfm_hdr->wfm_cs);
+                return -EINVAL;
+        }
+        wfm_hdr->mc += 1;
+        wfm_hdr->trc += 1;
+        for (i = 0; i < 5; i++) {
+                if (*(wfm_hdr->stuff2a + i) != 0) {
+                        printk(KERN_ERR "Error: unexpected value in padding\n");
+                        return -EINVAL;
+                }
+        }
+
+        /* calculating trn. trn is something used to index into
+        the waveform. presumably selecting the right one for the
+        desired temperature. it works out the offset of the first
+        v that exceeds the specified temperature */
+        if ((sizeof(*wfm_hdr) + wfm_hdr->trc) > size)
+                return -EINVAL;
+
+        for (i = sizeof(*wfm_hdr); i <= sizeof(*wfm_hdr) + wfm_hdr->trc; i++) {
+                if (mem[i] > t) {
+                        trn = i - sizeof(*wfm_hdr) - 1;
+                        break;
+                }
+        }
+
+        /* check temperature range table checksum */
+        cksum_idx = sizeof(*wfm_hdr) + wfm_hdr->trc + 1;
+        if (cksum_idx > size)
+                return -EINVAL;
+        cksum = calc_cksum(sizeof(*wfm_hdr), cksum_idx, mem);
+        if (cksum != mem[cksum_idx]) {
+                printk(KERN_ERR "Error: bad temperature range table cksum"
+                                " %x != %x\n", cksum, mem[cksum_idx]);
+                return -EINVAL;
+        }
+
+        /* check waveform mode table address checksum */
+        wmta = le32_to_cpu(get_unaligned((__le32 *) wfm_hdr->wmta));
+        wmta &= 0x00FFFFFF;
+        cksum_idx = wmta + m*4 + 3;
+        if (cksum_idx > size)
+                return -EINVAL;
+        cksum = calc_cksum(cksum_idx - 3, cksum_idx, mem);
+        if (cksum != mem[cksum_idx]) {
+                printk(KERN_ERR "Error: bad mode table address cksum"
+                                " %x != %x\n", cksum, mem[cksum_idx]);
+                return -EINVAL;
+        }
+
+        /* check waveform temperature table address checksum */
+        tta = le32_to_cpu(get_unaligned((int *) (mem + wmta + m*4)));
+        tta &= 0x00FFFFFF;
+        cksum_idx = tta + trn*4 + 3;
+        if (cksum_idx > size)
+                return -EINVAL;
+        cksum = calc_cksum(cksum_idx - 3, cksum_idx, mem);
+        if (cksum != mem[cksum_idx]) {
+                printk(KERN_ERR "Error: bad temperature table address cksum"
+                        " %x != %x\n", cksum, mem[cksum_idx]);
+                return -EINVAL;
+        }
+
+        /* here we do the real work of putting the waveform into the
+        metromem buffer. this does runlength decoding of the waveform */
+        wfm_idx = le32_to_cpu(get_unaligned((__le32 *) (mem + tta + trn*4)));
+        wfm_idx &= 0x00FFFFFF;
+        owfm_idx = wfm_idx;
+        if (wfm_idx > size)
+                return -EINVAL;
+        while (wfm_idx < size) {
+                unsigned char rl;
+                v = mem[wfm_idx++];
+                if (v == wfm_hdr->swtb) {
+                        while (((v = mem[wfm_idx++]) != wfm_hdr->swtb) &&
+                                wfm_idx < size)
+                                metromem[mem_idx++] = v;
+
+                        continue;
+                }
+
+                if (v == wfm_hdr->endb)
+                        break;
+
+                rl = mem[wfm_idx++];
+                for (i = 0; i <= rl; i++)
+                        metromem[mem_idx++] = v;
+        }
+
+        cksum_idx = wfm_idx;
+        if (cksum_idx > size)
+                return -EINVAL;
+        cksum = calc_cksum(owfm_idx, cksum_idx, mem);
+        if (cksum != mem[cksum_idx]) {
+                printk(KERN_ERR "Error: bad waveform data cksum"
+                                " %x != %x\n", cksum, mem[cksum_idx]);
+                return -EINVAL;
+        }
+        *frame_count = (mem_idx/64);
+
+        return 0;
+}
+
+/* register offsets for gpio control */
+#define LED_GPIO_PIN 51
+#define STDBY_GPIO_PIN 48
+#define RST_GPIO_PIN 49
+#define RDY_GPIO_PIN 32
+#define ERR_GPIO_PIN 17
+#define PCBPWR_GPIO_PIN 16
+
+#define AF_SEL_GPIO_N 0x3
+#define GAFR0_U_OFFSET(pin) ((pin - 16) * 2)
+#define GAFR1_L_OFFSET(pin) ((pin - 32) * 2)
+#define GAFR1_U_OFFSET(pin) ((pin - 48) * 2)
+#define GPDR1_OFFSET(pin) (pin - 32)
+#define GPCR1_OFFSET(pin) (pin - 32)
+#define GPSR1_OFFSET(pin) (pin - 32)
+#define GPCR0_OFFSET(pin) (pin)
+#define GPSR0_OFFSET(pin) (pin)
+
+static void metronome_set_gpio_output(int pin, int val)
+{
+        u8 index;
+
+        index = pin >> 4;
+
+        switch (index) {
+        case 1:
+                if (val)
+                        GPSR0 |= (1 << GPSR0_OFFSET(pin));
+                else
+                        GPCR0 |= (1 << GPCR0_OFFSET(pin));
+                break;
+        case 2:
+                break;
+        case 3:
+                if (val)
+                        GPSR1 |= (1 << GPSR1_OFFSET(pin));
+                else
+                        GPCR1 |= (1 << GPCR1_OFFSET(pin));
+                break;
+        default:
+                printk(KERN_ERR "unimplemented\n");
+        }
+}
+
+static void __devinit metronome_init_gpio_pin(int pin, int dir)
+{
+        u8 index;
+        /* dir 0 is output, 1 is input
+        - do 2 things here:
+        - set gpio alternate function to standard gpio
+        - set gpio direction to input or output  */
+
+        index = pin >> 4;
+        switch (index) {
+        case 1:
+                GAFR0_U &= ~(AF_SEL_GPIO_N << GAFR0_U_OFFSET(pin));
+
+                if (dir)
+                        GPDR0 &= ~(1 << pin);
+                else
+                        GPDR0 |= (1 << pin);
+                break;
+        case 2:
+                GAFR1_L &= ~(AF_SEL_GPIO_N << GAFR1_L_OFFSET(pin));
+
+                if (dir)
+                        GPDR1 &= ~(1 << GPDR1_OFFSET(pin));
+                else
+                        GPDR1 |= (1 << GPDR1_OFFSET(pin));
+                break;
+        case 3:
+                GAFR1_U &= ~(AF_SEL_GPIO_N << GAFR1_U_OFFSET(pin));
+
+                if (dir)
+                        GPDR1 &= ~(1 << GPDR1_OFFSET(pin));
+                else
+                        GPDR1 |= (1 << GPDR1_OFFSET(pin));
+                break;
+        default:
+                printk(KERN_ERR "unimplemented\n");
+        }
+}
+
+static void __devinit metronome_init_gpio_regs(void)
+{
+        metronome_init_gpio_pin(LED_GPIO_PIN, 0);
+        metronome_set_gpio_output(LED_GPIO_PIN, 0);
+
+        metronome_init_gpio_pin(STDBY_GPIO_PIN, 0);
+        metronome_set_gpio_output(STDBY_GPIO_PIN, 0);
+
+        metronome_init_gpio_pin(RST_GPIO_PIN, 0);
+        metronome_set_gpio_output(RST_GPIO_PIN, 0);
+
+        metronome_init_gpio_pin(RDY_GPIO_PIN, 1);
+
+        metronome_init_gpio_pin(ERR_GPIO_PIN, 1);
+
+        metronome_init_gpio_pin(PCBPWR_GPIO_PIN, 0);
+        metronome_set_gpio_output(PCBPWR_GPIO_PIN, 0);
+}
+
+static void metronome_disable_lcd_controller(struct metronomefb_par *par)
+{
+        LCSR = 0xffffffff;      /* Clear LCD Status Register */
+        LCCR0 |= LCCR0_DIS;     /* Disable LCD Controller */
+
+        /* we reset and just wait for things to settle */
+        msleep(200);
+}
+
+static void metronome_enable_lcd_controller(struct metronomefb_par *par)
+{
+        LCSR = 0xffffffff;
+        FDADR0 = par->metromem_desc_dma;
+        LCCR0 |= LCCR0_ENB;
+}
+
+static void __devinit metronome_init_lcdc_regs(struct metronomefb_par *par)
+{
+        /* here we do:
+        - disable the lcd controller
+        - setup lcd control registers
+        - setup dma descriptor
+        - reenable lcd controller
+        */
+
+        /* disable the lcd controller */
+        metronome_disable_lcd_controller(par);
+
+        /* setup lcd control registers */
+        LCCR0 = LCCR0_LDM | LCCR0_SFM | LCCR0_IUM | LCCR0_EFM | LCCR0_PAS
+                | LCCR0_QDM | LCCR0_BM | LCCR0_OUM;
+
+        LCCR1 = (epd_frame_table[0].fw/2 - 1) /* pixels per line */
+                | (27 << 10) /* hsync pulse width - 1 */
+                | (33 << 16) /* eol pixel count */
+                | (33 << 24); /* bol pixel count */
+
+        LCCR2 = (epd_frame_table[0].fh - 1) /* lines per panel */
+                | (24 << 10) /* vsync pulse width - 1 */
+                | (2 << 16) /* eof pixel count */
+                | (0 << 24); /* bof pixel count */
+
+        LCCR3 = 2 /* pixel clock divisor */
+                | (24 << 8) /* AC Bias pin freq */
+                | LCCR3_16BPP /* BPP */
+                | LCCR3_PCP;  /* PCP falling edge */
+
+        /* setup dma descriptor */
+        par->metromem_desc->mFDADR0 = par->metromem_desc_dma;
+        par->metromem_desc->mFSADR0 = par->metromem_dma;
+        par->metromem_desc->mFIDR0 = 0;
+        par->metromem_desc->mLDCMD0 = epd_frame_table[0].fw
+                                        * epd_frame_table[0].fh;
+        /* reenable lcd controller */
+        metronome_enable_lcd_controller(par);
+}
+
+static int metronome_display_cmd(struct metronomefb_par *par)
+{
+        int i;
+        u16 cs;
+        u16 opcode;
+        static u8 borderval;
+        u8 *ptr;
+
+        /* setup display command
+        we can't immediately set the opcode since the controller
+        will try parse the command before we've set it all up
+        so we just set cs here and set the opcode at the end */
+
+        ptr = par->metromem;
+
+        if (par->metromem_cmd->opcode == 0xCC40)
+                opcode = cs = 0xCC41;
+        else
+                opcode = cs = 0xCC40;
+
+        /* set the args ( 2 bytes ) for display */
+        i = 0;
+        par->metromem_cmd->args[i] =    1 << 3 /* border update */
+                                        | ((borderval++ % 4) & 0x0F) << 4
+                                        | (par->frame_count - 1) << 8;
+        cs += par->metromem_cmd->args[i++];
+
+        /* the rest are 0 */
+        memset((u8 *) (par->metromem_cmd->args + i), 0, (32-i)*2);
+
+        par->metromem_cmd->csum = cs;
+        par->metromem_cmd->opcode = opcode; /* display cmd */
+
+        i = wait_event_interruptible_timeout(par->waitq, (GPLR1 & 0x01), HZ);
+        return i;
+}
+
+static int __devinit metronome_powerup_cmd(struct metronomefb_par *par)
+{
+        int i;
+        u16 cs;
+
+        /* setup power up command */
+        par->metromem_cmd->opcode = 0x1234; /* pwr up pseudo cmd */
+        cs = par->metromem_cmd->opcode;
+
+        /* set pwr1,2,3 to 1024 */
+        for (i = 0; i < 3; i++) {
+                par->metromem_cmd->args[i] = 1024;
+                cs += par->metromem_cmd->args[i];
+        }
+
+        /* the rest are 0 */
+        memset((u8 *) (par->metromem_cmd->args + i), 0, (32-i)*2);
+
+        par->metromem_cmd->csum = cs;
+
+        msleep(1);
+        metronome_set_gpio_output(RST_GPIO_PIN, 1);
+
+        msleep(1);
+        metronome_set_gpio_output(STDBY_GPIO_PIN, 1);
+
+        i = wait_event_timeout(par->waitq, (GPLR1 & 0x01), HZ);
+        return i;
+}
+
+static int __devinit metronome_config_cmd(struct metronomefb_par *par)
+{
+        int i;
+        u16 cs;
+
+        /* setup config command
+        we can't immediately set the opcode since the controller
+        will try parse the command before we've set it all up
+        so we just set cs here and set the opcode at the end */
+
+        cs = 0xCC10;
+
+        /* set the 12 args ( 8 bytes ) for config. see spec for meanings */
+        i = 0;
+        par->metromem_cmd->args[i] =    15 /* sdlew */
+                                        | 2 << 8 /* sdosz */
+                                        | 0 << 11 /* sdor */
+                                        | 0 << 12 /* sdces */
+                                        | 0 << 15; /* sdcer */
+        cs += par->metromem_cmd->args[i++];
+
+        par->metromem_cmd->args[i] =    42 /* gdspl */
+                                        | 1 << 8 /* gdr1 */
+                                        | 1 << 9 /* sdshr */
+                                        | 0 << 15; /* gdspp */
+        cs += par->metromem_cmd->args[i++];
+
+        par->metromem_cmd->args[i] =    18 /* gdspw */
+                                        | 0 << 15; /* dispc */
+        cs += par->metromem_cmd->args[i++];
+
+        par->metromem_cmd->args[i] =    599 /* vdlc */
+                                        | 0 << 11 /* dsi */
+                                        | 0 << 12; /* dsic */
+        cs += par->metromem_cmd->args[i++];
+
+        /* the rest are 0 */
+        memset((u8 *) (par->metromem_cmd->args + i), 0, (32-i)*2);
+
+        par->metromem_cmd->csum = cs;
+        par->metromem_cmd->opcode = 0xCC10; /* config cmd */
+
+        i = wait_event_timeout(par->waitq, (GPLR1 & 0x01), HZ);
+        return i;
+}
+
+static int __devinit metronome_init_cmd(struct metronomefb_par *par)
+{
+        int i;
+        u16 cs;
+
+        /* setup init command
+        we can't immediately set the opcode since the controller
+        will try parse the command before we've set it all up
+        so we just set cs here and set the opcode at the end */
+
+        cs = 0xCC20;
+
+        /* set the args ( 2 bytes ) for init */
+        i = 0;
+        par->metromem_cmd->args[i] = 0;
+        cs += par->metromem_cmd->args[i++];
+
+        /* the rest are 0 */
+        memset((u8 *) (par->metromem_cmd->args + i), 0, (32-i)*2);
+
+        par->metromem_cmd->csum = cs;
+        par->metromem_cmd->opcode = 0xCC20; /* init cmd */
+
+        i = wait_event_timeout(par->waitq, (GPLR1 & 0x01), HZ);
+        return i;
+}
+
+static int __devinit metronome_init_regs(struct metronomefb_par *par)
+{
+        int res;
+
+        metronome_init_gpio_regs();
+        metronome_init_lcdc_regs(par);
+
+        res = metronome_powerup_cmd(par);
+        if (res)
+                return res;
+
+        res = metronome_config_cmd(par);
+        if (res)
+                return res;
+
+        res = metronome_init_cmd(par);
+        if (res)
+                return res;
+
+        return res;
+}
+
+static void metronomefb_dpy_update(struct metronomefb_par *par)
+{
+        u16 cksum;
+        unsigned char *buf = (unsigned char __force *)par->info->screen_base;
+
+        /* copy from vm to metromem */
+        memcpy(par->metromem_img, buf, DPY_W*DPY_H);
+
+        cksum = calc_img_cksum((u16 *) par->metromem_img,
+                                (epd_frame_table[0].fw * DPY_H)/2);
+        *((u16 *) (par->metromem_img) +
+                        (epd_frame_table[0].fw * DPY_H)/2) = cksum;
+        metronome_display_cmd(par);
+}
+
+static u16 metronomefb_dpy_update_page(struct metronomefb_par *par, int index)
+{
+        int i;
+        u16 csum = 0;
+        u16 *buf = (u16 __force *) (par->info->screen_base + index);
+        u16 *img = (u16 *) (par->metromem_img + index);
+
+        /* swizzle from vm to metromem and recalc cksum at the same time*/
+        for (i = 0; i < PAGE_SIZE/2; i++) {
+                *(img + i) = (buf[i] << 5) & 0xE0E0;
+                csum += *(img + i);
+        }
+        return csum;
+}
+
+/* this is called back from the deferred io workqueue */
+static void metronomefb_dpy_deferred_io(struct fb_info *info,
+                                struct list_head *pagelist)
+{
+        u16 cksum;
+        struct page *cur;
+        struct fb_deferred_io *fbdefio = info->fbdefio;
+        struct metronomefb_par *par = info->par;
+
+        /* walk the written page list and swizzle the data */
+        list_for_each_entry(cur, &fbdefio->pagelist, lru) {
+                cksum = metronomefb_dpy_update_page(par,
+                                        (cur->index << PAGE_SHIFT));
+                par->metromem_img_csum -= par->csum_table[cur->index];
+                par->csum_table[cur->index] = cksum;
+                par->metromem_img_csum += cksum;
+        }
+
+        metronome_display_cmd(par);
+}
+
+static void metronomefb_fillrect(struct fb_info *info,
+                                   const struct fb_fillrect *rect)
+{
+        struct metronomefb_par *par = info->par;
+
+        cfb_fillrect(info, rect);
+        metronomefb_dpy_update(par);
+}
+
+static void metronomefb_copyarea(struct fb_info *info,
+                                   const struct fb_copyarea *area)
+{
+        struct metronomefb_par *par = info->par;
+
+        cfb_copyarea(info, area);
+        metronomefb_dpy_update(par);
+}
+
+static void metronomefb_imageblit(struct fb_info *info,
+                                const struct fb_image *image)
+{
+        struct metronomefb_par *par = info->par;
+
+        cfb_imageblit(info, image);
+        metronomefb_dpy_update(par);
+}
+
+/*
+ * this is the slow path from userspace. they can seek and write to
+ * the fb. it is based on fb_sys_write
+ */
+static ssize_t metronomefb_write(struct fb_info *info, const char __user *buf,
+                                size_t count, loff_t *ppos)
+{
+        struct metronomefb_par *par = info->par;
+        unsigned long p = *ppos;
+        void *dst;
+        int err = 0;
+        unsigned long total_size;
+
+        if (info->state != FBINFO_STATE_RUNNING)
+                return -EPERM;
+
+        total_size = info->fix.smem_len;
+
+        if (p > total_size)
+                return -EFBIG;
+
+        if (count > total_size) {
+                err = -EFBIG;
+                count = total_size;
+        }
+
+        if (count + p > total_size) {
+                if (!err)
+                        err = -ENOSPC;
+
+                count = total_size - p;
+        }
+
+        dst = (void __force *) (info->screen_base + p);
+
+        if (copy_from_user(dst, buf, count))
+                err = -EFAULT;
+
+        if  (!err)
+                *ppos += count;
+
+        metronomefb_dpy_update(par);
+
+        return (err) ? err : count;
+}
+
+static struct fb_ops metronomefb_ops = {
+        .owner          = THIS_MODULE,
+        .fb_write       = metronomefb_write,
+        .fb_fillrect    = metronomefb_fillrect,
+        .fb_copyarea    = metronomefb_copyarea,
+        .fb_imageblit   = metronomefb_imageblit,
+};
+
+static struct fb_deferred_io metronomefb_defio = {
+        .delay          = HZ,
+        .deferred_io    = metronomefb_dpy_deferred_io,
+};
+
+static irqreturn_t metronome_handle_irq(int irq, void *dev_id)
+{
+        struct fb_info *info = dev_id;
+        struct metronomefb_par *par = info->par;
+
+        wake_up_interruptible(&par->waitq);
+        return IRQ_HANDLED;
+}
+
+static int __devinit metronomefb_probe(struct platform_device *dev)
+{
+        struct fb_info *info;
+        int retval = -ENOMEM;
+        int videomemorysize;
+        unsigned char *videomemory;
+        struct metronomefb_par *par;
+        const struct firmware *fw_entry;
+        int cmd_size, wfm_size, img_size, padding_size, totalsize;
+        int i;
+
+        /* we have two blocks of memory.
+        info->screen_base which is vm, and is the fb used by apps.
+        par->metromem which is physically contiguous memory and
+        contains the display controller commands, waveform,
+        processed image data and padding. this is the data pulled
+        by the pxa255's LCD controller and pushed to Metronome */
+
+        videomemorysize = (DPY_W*DPY_H);
+        videomemory = vmalloc(videomemorysize);
+        if (!videomemory)
+                return retval;
+
+        memset(videomemory, 0, videomemorysize);
+
+        info = framebuffer_alloc(sizeof(struct metronomefb_par), &dev->dev);
+        if (!info)
+                goto err_vfree;
+
+        info->screen_base = (char __iomem *) videomemory;
+        info->fbops = &metronomefb_ops;
+
+        info->var = metronomefb_var;
+        info->fix = metronomefb_fix;
+        info->fix.smem_len = videomemorysize;
+        par = info->par;
+        par->info = info;
+        init_waitqueue_head(&par->waitq);
+
+        /* this table caches per page csum values. */
+        par->csum_table = vmalloc(videomemorysize/PAGE_SIZE);
+        if (!par->csum_table)
+                goto err_csum_table;
+
+        /* the metromem buffer is divided as follows:
+        command | CRC | padding
+        16kb waveform data | CRC | padding
+        image data | CRC
+        and an extra 256 bytes for dma descriptors
+        eg: IW=832 IH=622 WS=128
+        */
+
+        cmd_size = 1 * epd_frame_table[0].fw;
+        wfm_size = ((16*1024 + 2 + epd_frame_table[0].fw - 1)
+                        / epd_frame_table[0].fw) * epd_frame_table[0].fw;
+        img_size = epd_frame_table[0].fh * epd_frame_table[0].fw;
+        padding_size = 4 * epd_frame_table[0].fw;
+        totalsize = cmd_size + wfm_size + img_size + padding_size;
+        par->metromemsize = PAGE_ALIGN(totalsize + 256);
+        DPRINTK("desired memory size = %d\n", par->metromemsize);
+        dev->dev.coherent_dma_mask = 0xffffffffull;
+        par->metromem = dma_alloc_writecombine(&dev->dev, par->metromemsize,
+                                                &par->metromem_dma, GFP_KERNEL);
+        if (!par->metromem) {
+                printk(KERN_ERR
+                        "metronomefb: unable to allocate dma buffer\n");
+                goto err_vfree;
+        }
+
+        info->fix.smem_start = par->metromem_dma;
+        par->metromem_cmd = (struct metromem_cmd *) par->metromem;
+        par->metromem_wfm = par->metromem + cmd_size;
+        par->metromem_img = par->metromem + cmd_size + wfm_size;
+        par->metromem_img_csum = (u16 *) (par->metromem_img +
+                                        (epd_frame_table[0].fw * DPY_H));
+        DPRINTK("img offset=0x%x\n", cmd_size + wfm_size);
+        par->metromem_desc = (struct metromem_desc *) (par->metromem + cmd_size
+                                        + wfm_size + img_size + padding_size);
+        par->metromem_desc_dma = par->metromem_dma + cmd_size + wfm_size
+                                 + img_size + padding_size;
+
+        /* load the waveform in. assume mode 3, temp 31 for now */
+        /*      a) request the waveform file from userspace
+                b) process waveform and decode into metromem */
+
+        retval = request_firmware(&fw_entry, "waveform.wbf", &dev->dev);
+        if (retval < 0) {
+                printk(KERN_ERR "metronomefb: couldn't get waveform\n");
+                goto err_dma_free;
+        }
+
+        retval = load_waveform((u8 *) fw_entry->data, fw_entry->size,
+                                par->metromem_wfm, 3, 31, &par->frame_count);
+        if (retval < 0) {
+                printk(KERN_ERR "metronomefb: couldn't process waveform\n");
+                goto err_ld_wfm;
+        }
+        release_firmware(fw_entry);
+
+        retval = request_irq(IRQ_GPIO(RDY_GPIO_PIN), metronome_handle_irq,
+                                IRQF_DISABLED, "Metronome", info);
+        if (retval) {
+                dev_err(&dev->dev, "request_irq failed: %d\n", retval);
+                goto err_ld_wfm;
+        }
+        set_irq_type(IRQ_GPIO(RDY_GPIO_PIN), IRQT_FALLING);
+
+        retval = metronome_init_regs(par);
+        if (retval < 0)
+                goto err_free_irq;
+
+        info->flags = FBINFO_FLAG_DEFAULT;
+
+        info->fbdefio = &metronomefb_defio;
+        fb_deferred_io_init(info);
+
+        retval = fb_alloc_cmap(&info->cmap, 8, 0);
+        if (retval < 0) {
+                printk(KERN_ERR "Failed to allocate colormap\n");
+                goto err_fb_rel;
+        }
+
+        /* set cmap */
+        for (i = 0; i < 8; i++)
+                info->cmap.red[i] = (((2*i)+1)*(0xFFFF))/16;
+        memcpy(info->cmap.green, info->cmap.red, sizeof(u16)*8);
+        memcpy(info->cmap.blue, info->cmap.red, sizeof(u16)*8);
+
+        retval = register_framebuffer(info);
+        if (retval < 0)
+                goto err_cmap;
+
+        platform_set_drvdata(dev, info);
+
+        printk(KERN_INFO
+                "fb%d: Metronome frame buffer device, using %dK of video"
+                " memory\n", info->node, videomemorysize >> 10);
+
+        return 0;
+
+err_cmap:
+        fb_dealloc_cmap(&info->cmap);
+err_fb_rel:
+        framebuffer_release(info);
+err_free_irq:
+        free_irq(IRQ_GPIO(RDY_GPIO_PIN), info);
+err_ld_wfm:
+        release_firmware(fw_entry);
+err_dma_free:
+        dma_free_writecombine(&dev->dev, par->metromemsize, par->metromem,
+                                par->metromem_dma);
+err_csum_table:
+        vfree(par->csum_table);
+err_vfree:
+        vfree(videomemory);
+        return retval;
+}
+
+static int __devexit metronomefb_remove(struct platform_device *dev)
+{
+        struct fb_info *info = platform_get_drvdata(dev);
+
+        if (info) {
+                struct metronomefb_par *par = info->par;
+                fb_deferred_io_cleanup(info);
+                dma_free_writecombine(&dev->dev, par->metromemsize,
+                                        par->metromem, par->metromem_dma);
+                fb_dealloc_cmap(&info->cmap);
+                vfree(par->csum_table);
+                unregister_framebuffer(info);
+                vfree((void __force *)info->screen_base);
+                free_irq(IRQ_GPIO(RDY_GPIO_PIN), info);
+                framebuffer_release(info);
+        }
+        return 0;
+}
+
+static struct platform_driver metronomefb_driver = {
+        .probe  = metronomefb_probe,
+        .remove = metronomefb_remove,
+        .driver = {
+                .name   = "metronomefb",
+        },
+};
+
+static struct platform_device *metronomefb_device;
+
+static int __init metronomefb_init(void)
+{
+        int ret;
+
+        if (!metronomefb_enable) {
+                printk(KERN_ERR
+                        "Use metronomefb_enable to enable the device\n");
+                return -ENXIO;
+        }
+
+        ret = platform_driver_register(&metronomefb_driver);
+        if (!ret) {
+                metronomefb_device = platform_device_alloc("metronomefb", 0);
+                if (metronomefb_device)
+                        ret = platform_device_add(metronomefb_device);
+                else
+                        ret = -ENOMEM;
+
+                if (ret) {
+                        platform_device_put(metronomefb_device);
+                        platform_driver_unregister(&metronomefb_driver);
+                }
+        }
+        return ret;
+
+}
+
+static void __exit metronomefb_exit(void)
+{
+        platform_device_unregister(metronomefb_device);
+        platform_driver_unregister(&metronomefb_driver);
+}
+
+module_param(metronomefb_enable, uint, 0);
+MODULE_PARM_DESC(metronomefb_enable, "Enable communication with Metronome");
+
+module_init(metronomefb_init);
+module_exit(metronomefb_exit);
+
+MODULE_DESCRIPTION("fbdev driver for Metronome controller");
+MODULE_AUTHOR("Jaya Kumar");
+MODULE_LICENSE("GPL");