bcma: add support for on-chip OTP memory used for SPROM storage

Wireless Broadcom chips can have either their SPROM data stored
on either external SPROM or on-chip OTP memory. Both are accessed
through the same register space. This patch adds support for the
on-chip OTP memory.

Tested with:
BCM43224 OTP and SPROM
BCM4331 SPROM
BCM4313 OTP

This patch is in response to linux-wireless thread [1].

[1] http://article.gmane.org/gmane.linux.kernel.wireless.general/85426

Tested-by: Saul St. John <saul.stjohn@gmail.com>
Tested-by: Rafal Milecki <zajec5@gmail.com>
Tested-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 106 insertions, 20 deletions

diff --git a/drivers/bcma/sprom.c b/drivers/bcma/sprom.c
index fba8066857d2..cdcf75c0954f 100644
--- a/drivers/bcma/sprom.c
+++ b/drivers/bcma/sprom.c
@@ -300,37 +300,128 @@ static void bcma_sprom_extract_r8(struct bcma_bus *bus, const u16 *sprom)
              SSB_SROM8_FEM_ANTSWLUT_SHIFT);
 }
 
-static bool bcma_is_sprom_available(struct bcma_bus *bus)
+/*
+ * Indicates the presence of external SPROM.
+ */
+static bool bcma_sprom_ext_available(struct bcma_bus *bus)
 {
-        u32 sromctrl;
+        u32 chip_status;
+        u32 srom_control;
+        u32 present_mask;
 
-        if (!(bus->drv_cc.capabilities & BCMA_CC_CAP_SPROM))
-                return false;
+        if (bus->drv_cc.core->id.rev >= 31) {
+                if (!(bus->drv_cc.capabilities & BCMA_CC_CAP_SPROM))
+                        return false;
 
-        if (bus->drv_cc.core->id.rev >= 32) {
-                sromctrl = bcma_read32(bus->drv_cc.core, BCMA_CC_SROM_CONTROL);
-                return sromctrl & BCMA_CC_SROM_CONTROL_PRESENT;
+                srom_control = bcma_read32(bus->drv_cc.core,
+                                           BCMA_CC_SROM_CONTROL);
+                return srom_control & BCMA_CC_SROM_CONTROL_PRESENT;
         }
-        return true;
+
+        /* older chipcommon revisions use chip status register */
+        chip_status = bcma_read32(bus->drv_cc.core, BCMA_CC_CHIPSTAT);
+        switch (bus->chipinfo.id) {
+        case 0x4313:
+                present_mask = BCMA_CC_CHIPST_4313_SPROM_PRESENT;
+                break;
+
+        case 0x4331:
+                present_mask = BCMA_CC_CHIPST_4331_SPROM_PRESENT;
+                break;
+
+        default:
+                return true;
+        }
+
+        return chip_status & present_mask;
+}
+
+/*
+ * Indicates that on-chip OTP memory is present and enabled.
+ */
+static bool bcma_sprom_onchip_available(struct bcma_bus *bus)
+{
+        u32 chip_status;
+        u32 otpsize = 0;
+        bool present;
+
+        chip_status = bcma_read32(bus->drv_cc.core, BCMA_CC_CHIPSTAT);
+        switch (bus->chipinfo.id) {
+        case 0x4313:
+                present = chip_status & BCMA_CC_CHIPST_4313_OTP_PRESENT;
+                break;
+
+        case 0x4331:
+                present = chip_status & BCMA_CC_CHIPST_4331_OTP_PRESENT;
+                break;
+
+        case 43224:
+        case 43225:
+                /* for these chips OTP is always available */
+                present = true;
+                break;
+
+        default:
+                present = false;
+                break;
+        }
+
+        if (present) {
+                otpsize = bus->drv_cc.capabilities & BCMA_CC_CAP_OTPS;
+                otpsize >>= BCMA_CC_CAP_OTPS_SHIFT;
+        }
+
+        return otpsize != 0;
+}
+
+/*
+ * Verify OTP is filled and determine the byte
+ * offset where SPROM data is located.
+ *
+ * On error, returns 0; byte offset otherwise.
+ */
+static int bcma_sprom_onchip_offset(struct bcma_bus *bus)
+{
+        struct bcma_device *cc = bus->drv_cc.core;
+        u32 offset;
+
+        /* verify OTP status */
+        if ((bcma_read32(cc, BCMA_CC_OTPS) & BCMA_CC_OTPS_GU_PROG_HW) == 0)
+                return 0;
+
+        /* obtain bit offset from otplayout register */
+        offset = (bcma_read32(cc, BCMA_CC_OTPL) & BCMA_CC_OTPL_GURGN_OFFSET);
+        return BCMA_CC_SPROM + (offset >> 3);
 }
 
 int bcma_sprom_get(struct bcma_bus *bus)
 {
-        u16 offset;
+        u16 offset = BCMA_CC_SPROM;
         u16 *sprom;
         int err = 0;
 
         if (!bus->drv_cc.core)
                 return -EOPNOTSUPP;
 
-        if (!bcma_is_sprom_available(bus)) {
+        if (!bcma_sprom_ext_available(bus)) {
                 /*
-                 * Maybe there is no SPROM on the device?
-                 * Now we ask the arch code if there is some sprom
-                 * available for this device in some other storage.
+                 * External SPROM takes precedence so check
+                 * on-chip OTP only when no external SPROM
+                 * is present.
                  */
-                err = bcma_fill_sprom_with_fallback(bus, &bus->sprom);
-                return err;
+                if (bcma_sprom_onchip_available(bus)) {
+                        /* determine offset */
+                        offset = bcma_sprom_onchip_offset(bus);
+                }
+                if (!offset) {
+                        /*
+                         * Maybe there is no SPROM on the device?
+                         * Now we ask the arch code if there is some sprom
+                         * available for this device in some other storage.
+                         */
+                        err = bcma_fill_sprom_with_fallback(bus, &bus->sprom);
+                        return err;
+                }
         }
 
         sprom = kcalloc(SSB_SPROMSIZE_WORDS_R4, sizeof(u16),
@@ -341,11 +432,6 @@ int bcma_sprom_get(struct bcma_bus *bus)
         if (bus->chipinfo.id == 0x4331)
                 bcma_chipco_bcm4331_ext_pa_lines_ctl(&bus->drv_cc, false);
 
-        /* Most cards have SPROM moved by additional offset 0x30 (48 dwords).
-         * According to brcm80211 this applies to cards with PCIe rev >= 6
-         * TODO: understand this condition and use it */
-        offset = (bus->chipinfo.id == 0x4331) ? BCMA_CC_SPROM :
-                BCMA_CC_SPROM_PCIE6;
         pr_debug("SPROM offset 0x%x\n", offset);
         bcma_sprom_read(bus, offset, sprom);