@@ -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.
@@ -113,8 +123,29 @@ 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";
+ }
snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
table->serial_port.address, baud_rate);
@@ -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,
@@ -2370,12 +2363,14 @@ 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;
@@ -2729,11 +2724,17 @@ 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;
@@ -1155,6 +1155,7 @@ 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; }