3 files changed, 54 insertions, 20 deletions

diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index 4ac3e06b41d8..98aa8c808a33 100644
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c
@@ -17,6 +17,16 @@
 #include <linux/serial_core.h>
 
 /*
+ * Erratum 44 for QDF2432v1 and QDF2400v1 SoCs describes the BUSY bit as
+ * occasionally getting stuck as 1. To avoid the potential for a hang, check
+ * TXFE == 0 instead of BUSY == 1. This may not be suitable for all UART
+ * implementations, so only do so if an affected platform is detected in
+ * parse_spcr().
+ */
+bool qdf2400_e44_present;
+EXPORT_SYMBOL(qdf2400_e44_present);
+
+/*
  * Some Qualcomm Datacenter Technologies SoCs have a defective UART BUSY bit.
  * Detect them by examining the OEM fields in the SPCR header, similiar to PCI
  * quirk detection in pci_mcfg.c.
@@ -147,8 +157,30 @@ int __init parse_spcr(bool earlycon)
                 goto done;
         }
 
-        if (qdf2400_erratum_44_present(&table->header))
-                uart = "qdf2400_e44";
+        /*
+         * If the E44 erratum is required, then we need to tell the pl011
+         * driver to implement the work-around.
+         *
+         * The global variable is used by the probe function when it
+         * creates the UARTs, whether or not they're used as a console.
+         *
+         * If the user specifies "traditional" earlycon, the qdf2400_e44
+         * console name matches the EARLYCON_DECLARE() statement, and
+         * SPCR is not used.  Parameter "earlycon" is false.
+         *
+         * If the user specifies "SPCR" earlycon, then we need to update
+         * the console name so that it also says "qdf2400_e44".  Parameter
+         * "earlycon" is true.
+         *
+         * For consistency, if we change the console name, then we do it
+         * for everyone, not just earlycon.
+         */
+        if (qdf2400_erratum_44_present(&table->header)) {
+                qdf2400_e44_present = true;
+                if (earlycon)
+                        uart = "qdf2400_e44";
+        }
+
         if (xgene_8250_erratum_present(table))
                 iotype = "mmio32";
 
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 8a857bb34fbb..1888d168a41c 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -142,15 +142,7 @@ static struct vendor_data vendor_sbsa = {
         .fixed_options          = true,
 };
 
-/*
- * Erratum 44 for QDF2432v1 and QDF2400v1 SoCs describes the BUSY bit as
- * occasionally getting stuck as 1. To avoid the potential for a hang, check
- * TXFE == 0 instead of BUSY == 1. This may not be suitable for all UART
- * implementations, so only do so if an affected platform is detected in
- * parse_spcr().
- */
-static bool qdf2400_e44_present = false;
-
+#ifdef CONFIG_ACPI_SPCR_TABLE
 static struct vendor_data vendor_qdt_qdf2400_e44 = {
         .reg_offset             = pl011_std_offsets,
         .fr_busy                = UART011_FR_TXFE,
@@ -165,6 +157,7 @@ static struct vendor_data vendor_qdt_qdf2400_e44 = {
         .always_enabled         = true,
         .fixed_options          = true,
 };
+#endif
 
 static u16 pl011_st_offsets[REG_ARRAY_SIZE] = {
         [REG_DR] = UART01x_DR,
@@ -2375,12 +2368,14 @@ static int __init pl011_console_match(struct console *co, char *name, int idx,
         resource_size_t addr;
         int i;
 
-        if (strcmp(name, "qdf2400_e44") == 0) {
-                pr_info_once("UART: Working around QDF2400 SoC erratum 44");
-                qdf2400_e44_present = true;
-        } else if (strcmp(name, "pl011") != 0) {
+        /*
+         * Systems affected by the Qualcomm Technologies QDF2400 E44 erratum
+         * have a distinct console name, so make sure we check for that.
+         * The actual implementation of the erratum occurs in the probe
+         * function.
+         */
+        if ((strcmp(name, "qdf2400_e44") != 0) && (strcmp(name, "pl011") != 0))
                 return -ENODEV;
-        }
 
         if (uart_parse_earlycon(options, &iotype, &addr, &options))
                 return -ENODEV;
@@ -2734,11 +2729,17 @@ static int sbsa_uart_probe(struct platform_device *pdev)
         }
         uap->port.irq   = ret;
 
-        uap->reg_offset = vendor_sbsa.reg_offset;
-        uap->vendor     = qdf2400_e44_present ?
-                                        &vendor_qdt_qdf2400_e44 : &vendor_sbsa;
+#ifdef CONFIG_ACPI_SPCR_TABLE
+        if (qdf2400_e44_present) {
+                dev_info(&pdev->dev, "working around QDF2400 SoC erratum 44\n");
+                uap->vendor = &vendor_qdt_qdf2400_e44;
+        } else
+#endif
+                uap->vendor = &vendor_sbsa;
+
+        uap->reg_offset = uap->vendor->reg_offset;
         uap->fifosize   = 32;
-        uap->port.iotype = vendor_sbsa.access_32b ? UPIO_MEM32 : UPIO_MEM;
+        uap->port.iotype = uap->vendor->access_32b ? UPIO_MEM32 : UPIO_MEM;
         uap->port.ops   = &sbsa_uart_pops;
         uap->fixed_baud = baudrate;
 
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index c749eef1daa1..27b4b6615263 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1209,6 +1209,7 @@ static inline bool acpi_has_watchdog(void) { return false; }
 #endif
 
 #ifdef CONFIG_ACPI_SPCR_TABLE
+extern bool qdf2400_e44_present;
 int parse_spcr(bool earlycon);
 #else
 static inline int parse_spcr(bool earlycon) { return 0; }