tty/serial fixes for 4.13-rc5

Here are two tty serial driver fixes for 4.13-rc5.  One is a revert of a
 -rc1 patch that turned out to not be a good idea, and the other is a fix
 for the pl011 serial driver.
 
 Both have been in linux-next with no reported issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here are two tty serial driver fixes for 4.13-rc5. One is a revert of
  a -rc1 patch that turned out to not be a good idea, and the other is a
  fix for the pl011 serial driver.

  Both have been in linux-next with no reported issues"

* tag 'tty-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  Revert "serial: Delete dead code for CIR serial ports"
  tty: pl011: fix initialization order of QDF2400 E44

drivers/acpi/spcr.c

@@ -16,6 +16,16 @@
 #include <linux/kernel.h>
 #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
@@ -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";
 

drivers/tty/serial/8250/8250_core.c

@@ -1043,13 +1043,24 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
 		if (up->dl_write)
 			uart->dl_write = up->dl_write;
 
-		if (serial8250_isa_config != NULL)
+		if (uart->port.type != PORT_8250_CIR) {
-			serial8250_isa_config(0, &uart->port,
+			if (serial8250_isa_config != NULL)
-					&uart->capabilities);
+				serial8250_isa_config(0, &uart->port,
+						&uart->capabilities);
 
-		ret = uart_add_one_port(&serial8250_reg, &uart->port);
+			ret = uart_add_one_port(&serial8250_reg,
-		if (ret == 0)
+						&uart->port);
-			ret = uart->port.line;
+			if (ret == 0)
+				ret = uart->port.line;
+		} else {
+			dev_info(uart->port.dev,
+				"skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
+				uart->port.iobase,
+				(unsigned long long)uart->port.mapbase,
+				uart->port.irq);
+
+			ret = 0;
+		}
 	}
 	mutex_unlock(&serial_mutex);
 

drivers/tty/serial/amba-pl011.c

@@ -142,15 +142,7 @@ static struct vendor_data vendor_sbsa = {
 	.fixed_options		= true,
 };
 
-/*
+#ifdef CONFIG_ACPI_SPCR_TABLE
- * 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;
-
 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");
+	 * Systems affected by the Qualcomm Technologies QDF2400 E44 erratum
-		qdf2400_e44_present = true;
+	 * have a distinct console name, so make sure we check for that.
-	} else if (strcmp(name, "pl011") != 0) {
+	 * 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;
+#ifdef CONFIG_ACPI_SPCR_TABLE
-	uap->vendor	= qdf2400_e44_present ?
+	if (qdf2400_e44_present) {
-					&vendor_qdt_qdf2400_e44 : &vendor_sbsa;
+		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;
 

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; }