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From: Konrad Dybcio <konrad.dybcio@linaro.org>
Date: Mon, 22 Jan 2024 15:27:20 +0100
Subject: [PATCH] tty: serial: amba-pl011: Remove QDF2xxx workarounds
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Message-Id: <20240122-topic-qdf_cleanup_tty-v1-1-0415503184be@linaro.org>
To: Russell King <linux@armlinux.org.uk>, 
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
 Jiri Slaby <jirislaby@kernel.org>
Cc: Marijn Suijten <marijn.suijten@somainline.org>, 
 linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, 
 Konrad Dybcio <konrad.dybcio@linaro.org>

This SoC family was destined for server use, featuring Qualcomm's very
interesting Kryo cores (before "Kryo" became a marketing term for Arm
cores with small modifications). It did however not leave the labs of
Qualcomm and presumably some partners, nor was it ever productized.

Remove the workarounds, as they are long obsolete.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
Compile-tested only
---
 drivers/tty/serial/amba-pl011.c | 82 -----------------------------------------
 1 file changed, 82 deletions(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index fccec1698a54..c4df9cbc264b 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -152,23 +152,6 @@ static const struct vendor_data vendor_sbsa = {
 	.fixed_options		= true,
 };
 
-#ifdef CONFIG_ACPI_SPCR_TABLE
-static const struct vendor_data vendor_qdt_qdf2400_e44 = {
-	.reg_offset		= pl011_std_offsets,
-	.fr_busy		= UART011_FR_TXFE,
-	.fr_dsr			= UART01x_FR_DSR,
-	.fr_cts			= UART01x_FR_CTS,
-	.fr_ri			= UART011_FR_RI,
-	.inv_fr			= UART011_FR_TXFE,
-	.access_32b		= true,
-	.oversampling		= false,
-	.dma_threshold		= false,
-	.cts_event_workaround	= false,
-	.always_enabled		= true,
-	.fixed_options		= true,
-};
-#endif
-
 static u16 pl011_st_offsets[REG_ARRAY_SIZE] = {
 	[REG_DR] = UART01x_DR,
 	[REG_ST_DMAWM] = ST_UART011_DMAWM,
@@ -2468,15 +2451,6 @@ static int pl011_console_match(struct console *co, char *name, int idx,
 	resource_size_t addr;
 	int i;
 
-	/*
-	 * 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;
 
@@ -2517,22 +2491,6 @@ static struct console amba_console = {
 
 #define AMBA_CONSOLE	(&amba_console)
 
-static void qdf2400_e44_putc(struct uart_port *port, unsigned char c)
-{
-	while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
-		cpu_relax();
-	writel(c, port->membase + UART01x_DR);
-	while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE))
-		cpu_relax();
-}
-
-static void qdf2400_e44_early_write(struct console *con, const char *s, unsigned int n)
-{
-	struct earlycon_device *dev = con->data;
-
-	uart_console_write(&dev->port, s, n, qdf2400_e44_putc);
-}
-
 static void pl011_putc(struct uart_port *port, unsigned char c)
 {
 	while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
@@ -2611,29 +2569,6 @@ OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);
 
 OF_EARLYCON_DECLARE(pl011, "arm,sbsa-uart", pl011_early_console_setup);
 
-/*
- * On Qualcomm Datacenter Technologies QDF2400 SOCs affected by
- * Erratum 44, traditional earlycon can be enabled by specifying
- * "earlycon=qdf2400_e44,<address>".  Any options are ignored.
- *
- * Alternatively, you can just specify "earlycon", and the early console
- * will be enabled with the information from the SPCR table.  In this
- * case, the SPCR code will detect the need for the E44 work-around,
- * and set the console name to "qdf2400_e44".
- */
-static int __init
-qdf2400_e44_early_console_setup(struct earlycon_device *device,
-				const char *opt)
-{
-	if (!device->port.membase)
-		return -ENODEV;
-
-	device->con->write = qdf2400_e44_early_write;
-	return 0;
-}
-
-EARLYCON_DECLARE(qdf2400_e44, qdf2400_e44_early_console_setup);
-
 #else
 #define AMBA_CONSOLE	NULL
 #endif
@@ -2869,22 +2804,6 @@ static int pl011_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(pl011_dev_pm_ops, pl011_suspend, pl011_resume);
 
-#ifdef CONFIG_ACPI_SPCR_TABLE
-static void qpdf2400_erratum44_workaround(struct device *dev,
-					  struct uart_amba_port *uap)
-{
-	if (!qdf2400_e44_present)
-		return;
-
-	dev_info(dev, "working around QDF2400 SoC erratum 44\n");
-	uap->vendor = &vendor_qdt_qdf2400_e44;
-}
-#else
-static void qpdf2400_erratum44_workaround(struct device *dev,
-					  struct uart_amba_port *uap)
-{ /* empty */ }
-#endif
-
 static int sbsa_uart_probe(struct platform_device *pdev)
 {
 	struct uart_amba_port *uap;
@@ -2921,7 +2840,6 @@ static int sbsa_uart_probe(struct platform_device *pdev)
 	uap->port.irq	= ret;
 
 	uap->vendor = &vendor_sbsa;
-	qpdf2400_erratum44_workaround(&pdev->dev, uap);
 
 	uap->reg_offset	= uap->vendor->reg_offset;
 	uap->fifosize	= 32;

---
base-commit: 319fbd8fc6d339e0a1c7b067eed870c518a13a02
change-id: 20240122-topic-qdf_cleanup_tty-448ae426000d

Best regards,
-- 
Konrad Dybcio <konrad.dybcio@linaro.org>