STMD/HSI FFL: Modem Cold Reset not following SAS

BZ: 27564

Implemention of the modem cold reset according to the SAS:
- Set the RESET_BB_N pin to low before updating the PMIC register for
better sim protection

Faouaz TENOUTIT <faouazx.tenoutit@intel.com>

Change-Id: Ia544118e1f92d429082928e05895e37da4cf219a
Signed-off-by: Faouaz TENOUTIT <faouazx.tenoutit@intel.com>
Reviewed-on: http://android.intel.com:8080/50516
Reviewed-by: Roulliere, Pierre <pierre.roulliere@intel.com>
Reviewed-by: Predon, Frederic <frederic.predon@intel.com>
Tested-by: Lebsir, SamiX <samix.lebsir@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>

diff --git a/drivers/hsi/clients/hsi_ffl_tty.c b/drivers/hsi/clients/hsi_ffl_tty.c
index 5d1616a..fbe7092 100644 (file)
--- a/drivers/hsi/clients/hsi_ffl_tty.c
+++ b/drivers/hsi/clients/hsi_ffl_tty.c
@@ -3071,6 +3071,12 @@ static int hangup_reasons(char *val, const struct kernel_param *kp)
   *
   * This callback performs a cold reset once a "1" is written into
   * the /sys/module/hsi_ffl_tty/parameters/cold_reset_modem sysFS file
+  *
+  *
+  * To do a modem cold reset we have to:
+  * - Set the RESET_BB_N to low (better SIM protection)
+  * - Set the EXT1P35VREN field to low  during 20ms (V1P35CNT_W PMIC register)
+  * - set the EXT1P35VREN field to high during 10ms (V1P35CNT_W PMIC register)
   */
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 36)
 static int modem_cold_reset(const char *val, struct kernel_param *kp)
@@ -3078,80 +3084,58 @@ static int modem_cold_reset(const char *val, struct kernel_param *kp)
 static int modem_cold_reset(const char *val, const struct kernel_param *kp)
 #endif
 {
-       int ret = 0;
-       int err;
-       u16 addr;
-       u8 data;
-       u8 def_value;
        long request;
+       int err;
+       u16 addr = V1P35CNT_W;
+       u8 data, def_value;
+       struct ffl_ctx *ctx = ffl_drv.ctx[0]; /* Main context */
+       struct hsi_mid_platform_data *pd = ctx->client->device.platform_data;
 
        if (strict_strtol(val, 10, &request) < 0)
                return -EINVAL;
 
-       pr_debug(DRVNAME " - %s - start", __func__);
+       pr_info(DRVNAME " - %s (Modem cold reset requested !)", __func__);
 
-       /*
-        * The modem cold boot is done by the following sequence:
-        *  - Writes to PMIC register V1P35CNT_W to set EXT1P35VREN to low
-        *    during 20ms
-        *  - Writes to PMIC register V1P35CNT_W to set EXT1P35VREN to high
-        *    during 10ms
-        */
+       /* Set the reset_bb to low */
+       ctx->reset.ongoing = 1;
+       gpio_set_value(pd->gpio_mdm_rst_bbn, 0);
 
-       addr = V1P35CNT_W;
-       err = intel_scu_ipc_readv(&addr, &data, 2);
-       if (err != 0) {
+       /* Save the current register value */
+       err = intel_scu_ipc_readv(&addr, &def_value, 2);
+       if (err) {
                pr_err(DRVNAME " - %s -  read error: %d", __func__, err);
-               ret = -EINVAL;
-               goto exit_modem_cold_reset;
+               goto out;
        }
-       def_value = data;
 
-       addr = V1P35CNT_W;
+       /* Write the new register value (V1P35_OFF) */
        data = (def_value & 0xf8) | V1P35_OFF;
        err =  intel_scu_ipc_writev(&addr, &data, 1);
-       if (err != 0) {
+       if (err) {
                pr_err(DRVNAME " - %s -  write error: %d", __func__, err);
-               ret = -EINVAL;
-               goto exit_modem_cold_reset;
+               goto out;
        }
        usleep_range(COLD_BOOT_DELAY_OFF, COLD_BOOT_DELAY_OFF);
 
-       addr = V1P35CNT_W;
+       /* Write the new register value (V1P35_ON) */
        data = (def_value & 0xf8) | V1P35_ON;
        err =  intel_scu_ipc_writev(&addr, &data, 1);
-       if (err != 0) {
+       if (err) {
                pr_err(DRVNAME " - %s -  write error: %d", __func__, err);
-               ret = -EINVAL;
-               goto exit_modem_cold_reset;
+               goto out;
        }
        usleep_range(COLD_BOOT_DELAY_ON, COLD_BOOT_DELAY_ON);
 
-       addr = V1P35CNT_W;
-       err = intel_scu_ipc_readv(&addr, &data, 1);
-       if (err != 0) {
-               pr_err(DRVNAME " - %s -  read error: %d", __func__, err);
-               ret = -EINVAL;
-               goto exit_modem_cold_reset;
-       }
-
-       addr = V1P35CNT_W;
-       data = def_value;
-       err =  intel_scu_ipc_writev(&addr, &data, 1);
-       if (err != 0) {
+       /* Write back the initial register value */
+       err =  intel_scu_ipc_writev(&addr, &def_value, 1);
+       if (err) {
                pr_err(DRVNAME " - %s -  write error: %d", __func__, err);
-               ret = -EINVAL;
-               goto exit_modem_cold_reset;
-       }
-
-exit_modem_cold_reset:
-       pr_debug(DRVNAME " - %s - end", __func__);
-
-       /* do a reset_modem to perform a complete modem reset */
-       if (ret != -EINVAL)
+       } else {
+               /* Perform a complete modem reset */
                reset_modem(val, kp);
+       }
 
-       return ret;
+out:
+       return err;
 }
 
 /*
@@ -4127,4 +4111,3 @@ MODULE_AUTHOR("Olivier Stoltz Douchet <olivierx.stoltz-douchet@intel.com>");
 MODULE_DESCRIPTION("Fixed frame length protocol on HSI driver");
 MODULE_LICENSE("GPL");
 MODULE_VERSION("0.1-HSI-FFL");
-