Subject: [PATCH 2/2] amba/serial: amba-pl011: Bring back zx29 UART support

From: Stefan Dösinger <[email-masked]>
Date: Thu, 14 May 2026 00:34:57 +0300

This is based on code removed in commit 89d4f98ae90d ("ARM: remove zte
zx platform"). I did not bring back the zx29-uart .compatible as the
arm,primecell-periphid does the job.

Reviewed-by: Linus Walleij <[email-masked]>
Signed-off-by: Stefan Dösinger <[email-masked]>
---

Changes since v4:
Use ZTE's JEDEC ID instead of 0xfe for the DT-Provided AMBA ID.
---
 drivers/tty/serial/amba-pl011.c | 42 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 028e37ad8d79..8ed91e1da22b 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -240,6 +240,38 @@ static struct vendor_data vendor_nvidia = {
 	.get_fifosize		= get_fifosize_nvidia,
 };
 
+static const u16 pl011_zte_offsets[REG_ARRAY_SIZE] = {
+	[REG_DR] = ZX_UART011_DR,
+	[REG_FR] = ZX_UART011_FR,
+	[REG_LCRH_RX] = ZX_UART011_LCRH,
+	[REG_LCRH_TX] = ZX_UART011_LCRH,
+	[REG_IBRD] = ZX_UART011_IBRD,
+	[REG_FBRD] = ZX_UART011_FBRD,
+	[REG_CR] = ZX_UART011_CR,
+	[REG_IFLS] = ZX_UART011_IFLS,
+	[REG_IMSC] = ZX_UART011_IMSC,
+	[REG_RIS] = ZX_UART011_RIS,
+	[REG_MIS] = ZX_UART011_MIS,
+	[REG_ICR] = ZX_UART011_ICR,
+	[REG_DMACR] = ZX_UART011_DMACR,
+};
+
+static unsigned int get_fifosize_zte(struct amba_device *dev)
+{
+	return 16;
+}
+
+static struct vendor_data vendor_zte = {
+	.reg_offset		= pl011_zte_offsets,
+	.access_32b		= true,
+	.ifls			= UART011_IFLS_RX4_8 | UART011_IFLS_TX4_8,
+	.fr_busy		= ZX_UART01x_FR_BUSY,
+	.fr_dsr			= ZX_UART01x_FR_DSR,
+	.fr_cts			= ZX_UART01x_FR_CTS,
+	.fr_ri			= ZX_UART011_FR_RI,
+	.get_fifosize		= get_fifosize_zte,
+};
+
 /* Deals with DMA transactions */
 
 struct pl011_dmabuf {
@@ -3180,6 +3212,16 @@ static const struct amba_id pl011_ids[] = {
 		.mask	= 0x000fffff,
 		.data	= &vendor_nvidia,
 	},
+	{
+		/* This is an invented ID. The actual hardware that contains
+		 * these ZTE UARTs (zx29 boards) has no AMBA PIDs stored. ZTE
+		 * JEDEC ID (ignoring banks) and the "011" part number as used
+		 * by ARM.
+		 */
+		.id	= 0x0008c011,
+		.mask	= 0x000fffff,
+		.data	= &vendor_zte,
+	},
 	{ 0, 0 },
 };

-- 
2.53.0