drm/nouveau: implement parsing of DCB 2.2 GPIO table

Found on NV3x boards, this should allow voltage modifications to work
on these chipsets.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 63 insertions, 93 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_bios.c b/drivers/gpu/drm/nouveau/nouveau_bios.c
index 07171dd3c16..8d60bfdf6c7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bios.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bios.c
@@ -5762,8 +5762,14 @@ static uint16_t findstr(uint8_t *data, int n, const uint8_t *str, int len)
 static struct dcb_gpio_entry *
 new_gpio_entry(struct nvbios *bios)
 {
+        struct drm_device *dev = bios->dev;
         struct dcb_gpio_table *gpio = &bios->dcb.gpio;
 
+        if (gpio->entries >= DCB_MAX_NUM_GPIO_ENTRIES) {
+                NV_ERROR(dev, "exceeded maximum number of gpio entries!!\n");
+                return NULL;
+        }
+
         return &gpio->entry[gpio->entries++];
 }
 
@@ -5785,113 +5791,77 @@ nouveau_bios_gpio_entry(struct drm_device *dev, enum dcb_gpio_tag tag)
 }
 
 static void
-parse_dcb30_gpio_entry(struct nvbios *bios, uint16_t offset)
-{
-        struct dcb_gpio_entry *gpio;
-        uint16_t ent = ROM16(bios->data[offset]);
-        uint8_t line = ent & 0x1f,
-                tag = ent >> 5 & 0x3f,
-                flags = ent >> 11 & 0x1f;
-
-        if (tag == 0x3f)
-                return;
-
-        gpio = new_gpio_entry(bios);
-
-        gpio->tag = tag;
-        gpio->line = line;
-        gpio->invert = flags != 4;
-        gpio->entry = ent;
-}
-
-static void
-parse_dcb40_gpio_entry(struct nvbios *bios, uint16_t offset)
-{
-        uint32_t entry = ROM32(bios->data[offset]);
-        struct dcb_gpio_entry *gpio;
-
-        if ((entry & 0x0000ff00) == 0x0000ff00)
-                return;
-
-        gpio = new_gpio_entry(bios);
-        gpio->tag = (entry & 0x0000ff00) >> 8;
-        gpio->line = (entry & 0x0000001f) >> 0;
-        gpio->state_default = (entry & 0x01000000) >> 24;
-        gpio->state[0] = (entry & 0x18000000) >> 27;
-        gpio->state[1] = (entry & 0x60000000) >> 29;
-        gpio->entry = entry;
-}
-
-static void
 parse_dcb_gpio_table(struct nvbios *bios)
 {
         struct drm_device *dev = bios->dev;
-        uint16_t gpio_table_ptr = bios->dcb.gpio_table_ptr;
-        uint8_t *gpio_table = &bios->data[gpio_table_ptr];
-        int header_len = gpio_table[1],
-            entries = gpio_table[2],
-            entry_len = gpio_table[3];
-        void (*parse_entry)(struct nvbios *, uint16_t) = NULL;
+        struct dcb_gpio_entry *e;
+        u8 headerlen, entries, recordlen;
+        u8 *dcb, *gpio = NULL, *entry;
         int i;
 
-        if (bios->dcb.version >= 0x40) {
-                if (gpio_table_ptr && entry_len != 4) {
-                        NV_WARN(dev, "Invalid DCB GPIO table entry length.\n");
-                        return;
-                }
-
-                parse_entry = parse_dcb40_gpio_entry;
-
-        } else if (bios->dcb.version >= 0x30) {
-                if (gpio_table_ptr && entry_len != 2) {
-                        NV_WARN(dev, "Invalid DCB GPIO table entry length.\n");
-                        return;
-                }
-
-                parse_entry = parse_dcb30_gpio_entry;
+        dcb = ROMPTR(bios, bios->data[0x36]);
+        if (dcb[0] >= 0x30) {
+                gpio = ROMPTR(bios, dcb[10]);
+                if (!gpio)
+                        goto no_table;
 
-        } else if (bios->dcb.version >= 0x22) {
-                /*
-                 * DCBs older than v3.0 don't really have a GPIO
-                 * table, instead they keep some GPIO info at fixed
-                 * locations.
-                 */
-                uint16_t dcbptr = ROM16(bios->data[0x36]);
-                uint8_t *tvdac_gpio = &bios->data[dcbptr - 5];
+                headerlen = gpio[1];
+                entries   = gpio[2];
+                recordlen = gpio[3];
+        } else
+        if (dcb[0] >= 0x22) {
+                gpio = ROMPTR(bios, dcb[-15]);
+                if (!gpio)
+                        goto no_table;
+
+                headerlen = 3;
+                entries   = gpio[2];
+                recordlen = gpio[1];
+        } else {
+                NV_DEBUG(dev, "no/unknown gpio table on DCB 0x%02x\n", dcb[0]);
+                goto no_table;
+        }
 
-                if (tvdac_gpio[0] & 1) {
-                        struct dcb_gpio_entry *gpio = new_gpio_entry(bios);
+        entry = gpio + headerlen;
+        for (i = 0; i < entries; i++, entry += recordlen) {
+                e = new_gpio_entry(bios);
+                if (!e)
+                        break;
 
-                        gpio->tag = DCB_GPIO_TVDAC0;
-                        gpio->line = tvdac_gpio[1] >> 4;
-                        gpio->invert = tvdac_gpio[0] & 2;
-                }
-        } else {
-                /*
-                 * No systematic way to store GPIO info on pre-v2.2
-                 * DCBs, try to match the PCI device IDs.
-                 */
+                if (gpio[0] < 0x40) {
+                        e->entry = ROM16(entry[0]);
+                        e->tag = (e->entry & 0x07e0) >> 5;
+                        if (e->tag == 0x3f) {
+                                bios->dcb.gpio.entries--;
+                                continue;
+                        }
 
-                /* Apple iMac G4 NV18 */
-                if (nv_match_device(dev, 0x0189, 0x10de, 0x0010)) {
-                        struct dcb_gpio_entry *gpio = new_gpio_entry(bios);
+                        e->line = (e->entry & 0x001f);
+                        e->invert = ((e->entry & 0xf800) >> 11) != 4;
+                } else {
+                        e->entry = ROM32(entry[0]);
+                        e->tag = (e->entry & 0x0000ff00) >> 8;
+                        if (e->tag == 0xff) {
+                                bios->dcb.gpio.entries--;
+                                continue;
+                        }
 
-                        gpio->tag = DCB_GPIO_TVDAC0;
-                        gpio->line = 4;
+                        e->line = (e->entry & 0x0000001f) >> 0;
+                        e->state_default = (e->entry & 0x01000000) >> 24;
+                        e->state[0] = (e->entry & 0x18000000) >> 27;
+                        e->state[1] = (e->entry & 0x60000000) >> 29;
                 }
-
         }
 
-        if (!gpio_table_ptr)
-                return;
-
-        if (entries > DCB_MAX_NUM_GPIO_ENTRIES) {
-                NV_WARN(dev, "Too many entries in the DCB GPIO table.\n");
-                entries = DCB_MAX_NUM_GPIO_ENTRIES;
+no_table:
+        /* Apple iMac G4 NV18 */
+        if (nv_match_device(dev, 0x0189, 0x10de, 0x0010)) {
+                e = new_gpio_entry(bios);
+                if (e) {
+                        e->tag = DCB_GPIO_TVDAC0;
+                        e->line = 4;
+                }
         }
-
-        for (i = 0; i < entries; i++)
-                parse_entry(bios, gpio_table_ptr + header_len + entry_len * i);
 }
 
 struct dcb_connector_table_entry *