OMAP: DSS2: HDMI: clean up edid reading & fix checksum

Clean up reading of EDID by passing direct address to the block being
read, instead of start address of the whole EDID memory area. Rewrite
the loop which reads the EDID.

This also fixes the checksum calculation, which used to calculate the
checksum only for the first block.

Cc: Mythri P K <mythripk@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

diff --git a/drivers/video/omap2/dss/ti_hdmi.h b/drivers/video/omap2/dss/ti_hdmi.h
index acf102267700579d05b17110cb59b6b8836182f3..390cd85b122f8e4d64bcdd50b601070d6e36e07e 100644 (file)
--- a/drivers/video/omap2/dss/ti_hdmi.h
+++ b/drivers/video/omap2/dss/ti_hdmi.h
@@ -92,8 +92,7 @@ struct ti_hdmi_ip_ops {
 
        void (*phy_disable)(struct hdmi_ip_data *ip_data);
 
-       int (*read_edid)(struct hdmi_ip_data *ip_data,
-                       u8 *pedid, u16 max_length);
+       int (*read_edid)(struct hdmi_ip_data *ip_data, u8 *edid, int len);
 
        int (*pll_enable)(struct hdmi_ip_data *ip_data);
 
@@ -114,8 +113,7 @@ struct hdmi_ip_data {
 };
 int ti_hdmi_4xxx_phy_enable(struct hdmi_ip_data *ip_data);
 void ti_hdmi_4xxx_phy_disable(struct hdmi_ip_data *ip_data);
-int ti_hdmi_4xxx_read_edid(struct hdmi_ip_data *ip_data,
-                                       u8 *pedid, u16 max_length);
+int ti_hdmi_4xxx_read_edid(struct hdmi_ip_data *ip_data, u8 *edid, int len);
 void ti_hdmi_4xxx_wp_video_start(struct hdmi_ip_data *ip_data, bool start);
 int ti_hdmi_4xxx_pll_enable(struct hdmi_ip_data *ip_data);
 void ti_hdmi_4xxx_pll_disable(struct hdmi_ip_data *ip_data);

diff --git a/drivers/video/omap2/dss/ti_hdmi_4xxx_ip.c b/drivers/video/omap2/dss/ti_hdmi_4xxx_ip.c
index ecf854e2596ca05c201d58520c107c552ef66dd4..e9885dcc4122106503b503d4c7a73f894e96b8b2 100644 (file)
--- a/drivers/video/omap2/dss/ti_hdmi_4xxx_ip.c
+++ b/drivers/video/omap2/dss/ti_hdmi_4xxx_ip.c
@@ -310,8 +310,8 @@ static int hdmi_core_ddc_edid(struct hdmi_ip_data *ip_data,
                u8 *pedid, int ext)
 {
        void __iomem *base = hdmi_core_sys_base(ip_data);
-       u32 i, j;
-       char checksum = 0;
+       u32 i;
+       char checksum;
        u32 offset = 0;
 
        /* HDMI_CORE_DDC_STATUS_IN_PROG */
@@ -354,21 +354,31 @@ static int hdmi_core_ddc_edid(struct hdmi_ip_data *ip_data,
                return -EIO;
        }
 
-       i = ext * 128;
-       j = 0;
-       while (((REG_GET(base, HDMI_CORE_DDC_STATUS, 4, 4) == 1) ||
-               (REG_GET(base, HDMI_CORE_DDC_STATUS, 2, 2) == 0)) &&
-                       j < 128) {
+       for (i = 0; i < 0x80; ++i) {
+               int t;
 
-               if (REG_GET(base, HDMI_CORE_DDC_STATUS, 2, 2) == 0) {
-                       /* FIFO not empty */
-                       pedid[i++] = REG_GET(base, HDMI_CORE_DDC_DATA, 7, 0);
-                       j++;
+               /* IN_PROG */
+               if (REG_GET(base, HDMI_CORE_DDC_STATUS, 4, 4) == 0) {
+                       DSSERR("operation stopped when reading edid\n");
+                       return -EIO;
+               }
+
+               t = 0;
+               /* FIFO_EMPTY */
+               while (REG_GET(base, HDMI_CORE_DDC_STATUS, 2, 2) == 1) {
+                       if (t++ > 10000) {
+                               DSSERR("timeout reading edid\n");
+                               return -ETIMEDOUT;
+                       }
+                       udelay(1);
                }
+
+               pedid[i] = REG_GET(base, HDMI_CORE_DDC_DATA, 7, 0);
        }
 
-       for (j = 0; j < 128; j++)
-               checksum += pedid[j];
+       checksum = 0;
+       for (i = 0; i < 0x80; ++i)
+               checksum += pedid[i];
 
        if (checksum != 0) {
                pr_err("E-EDID checksum failed!!\n");
@@ -379,40 +389,31 @@ static int hdmi_core_ddc_edid(struct hdmi_ip_data *ip_data,
 }
 
 int ti_hdmi_4xxx_read_edid(struct hdmi_ip_data *ip_data,
-                               u8 *pedid, u16 max_length)
+                               u8 *edid, int len)
 {
-       int r = 0, n = 0, i = 0;
-       int max_ext_blocks = (max_length / 128) - 1;
-       int len;
+       int r, l;
+
+       if (len < 128)
+               return -EINVAL;
 
        r = hdmi_core_ddc_init(ip_data);
        if (r)
                return r;
 
-       r = hdmi_core_ddc_edid(ip_data, pedid, 0);
+       r = hdmi_core_ddc_edid(ip_data, edid, 0);
        if (r)
                return r;
 
-       len = 128;
-       n = pedid[0x7e];
-
-       /*
-        * README: need to comply with max_length set by the caller.
-        * Better implementation should be to allocate necessary
-        * memory to store EDID according to nb_block field found
-        * in first block
-        */
-       if (n > max_ext_blocks)
-               n = max_ext_blocks;
+       l = 128;
 
-       for (i = 1; i <= n; i++) {
-               r = hdmi_core_ddc_edid(ip_data, pedid, i);
+       if (len >= 128 * 2 && edid[0x7e] > 0) {
+               r = hdmi_core_ddc_edid(ip_data, edid + 0x80, 1);
                if (r)
                        return r;
-               len += 128;
+               l += 128;
        }
 
-       return len;
+       return l;
 }
 
 static void hdmi_core_init(struct hdmi_core_video_config *video_cfg,