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From: Shanker Donthineni <shankerd@codeaurora.org>
To: xen-devel <xen-devel@lists.xensource.com>,
	Julien Grall <julien.grall@arm.com>,
	Stefano Stabellini <sstabellini@kernel.org>
Cc: Andre Przywara <andre.przywara@arm.com>,
	Philip Elcan <pelcan@codeaurora.org>,
	Shanker Donthineni <shankerd@codeaurora.org>,
	Vikram Sethi <vikrams@codeaurora.org>,
	Wei Chen <wei.chen@linaro.org>
Subject: [PATCH V7 3/3] arm/acpi: Add Server Base System Architecture UART support
Date: Tue,  7 Jun 2016 14:04:04 -0500	[thread overview]
Message-ID: <1465326244-10802-3-git-send-email-shankerd@codeaurora.org> (raw)
In-Reply-To: <1465326244-10802-1-git-send-email-shankerd@codeaurora.org>

The ARM Server Base System Architecture describes a generic UART
interface. It doesn't support clock control registers, modem
control, DMA and hardware flow control features. So, extend the
driver probe() to handle SBSA interface and skip the accessing
PL011 registers that are not described in SBSA document
(ARM-DEN-0029 Version 3.0, 6 APPENDIX B: GENERIC UART).

Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Reviewed-by: Julien Grall <julien.grall@arm.com>
---
Changes since v3:
  Moved non-SBSA related changes to patches 1/3 and 2/3.

changes since v2:
  Edited commit text to include SBSA document version.
  Remove setting baudrate code completely as per Julien's suggestion.
  Support both the SBSA interface types ACPI_DBG2_SBSA & ACPI_DBG2_SBSA_32.
  Replace MIS references with combination of RIS & IMSC.

Changes since v1:
  Don't access UART registers that are not part of SBSA document.
  Move setting baudrate function to a separate function.

 xen/drivers/char/pl011.c | 54 ++++++++++++++++++++++++++++++++++--------------
 1 file changed, 39 insertions(+), 15 deletions(-)

diff --git a/xen/drivers/char/pl011.c b/xen/drivers/char/pl011.c
index 86fc463..d70ec99 100644
--- a/xen/drivers/char/pl011.c
+++ b/xen/drivers/char/pl011.c
@@ -41,6 +41,7 @@ static struct pl011 {
     /* struct timer timer; */
     /* unsigned int timeout_ms; */
     /* bool_t probing, intr_works; */
+    bool sbsa;  /* ARM SBSA generic interface */
 } pl011_com = {0};
 
 /* These parity settings can be ORed directly into the LCR. */
@@ -96,14 +97,17 @@ static void __init pl011_init_preirq(struct serial_port *port)
     /* No interrupts, please. */
     pl011_write(uart, IMSC, 0);
 
-    /* Definitely no DMA */
-    pl011_write(uart, DMACR, 0x0);
-
-    /* This write must follow FBRD and IBRD writes. */
-    pl011_write(uart, LCR_H, (uart->data_bits - 5) << 5
-                            | FEN
-                            | ((uart->stop_bits - 1) << 3)
-                            | uart->parity);
+    if ( !uart->sbsa )
+    {
+        /* Definitely no DMA */
+        pl011_write(uart, DMACR, 0x0);
+
+        /* This write must follow FBRD and IBRD writes. */
+        pl011_write(uart, LCR_H, (uart->data_bits - 5) << 5
+                                | FEN
+                                | ((uart->stop_bits - 1) << 3)
+                                | uart->parity);
+    }
     /* Clear errors */
     pl011_write(uart, RSR, 0);
 
@@ -111,10 +115,13 @@ static void __init pl011_init_preirq(struct serial_port *port)
     pl011_write(uart, IMSC, 0);
     pl011_write(uart, ICR, ALLI);
 
-    /* Enable the UART for RX and TX; keep RTS and DTR */
-    cr = pl011_read(uart, CR);
-    cr &= RTS | DTR;
-    pl011_write(uart, CR, cr | RXE | TXE | UARTEN);
+    if ( !uart->sbsa )
+    {
+        /* Enable the UART for RX and TX; keep RTS and DTR */
+        cr = pl011_read(uart, CR);
+        cr &= RTS | DTR;
+        pl011_write(uart, CR, cr | RXE | TXE | UARTEN);
+    }
 }
 
 static void __init pl011_init_postirq(struct serial_port *port)
@@ -216,7 +223,7 @@ static struct uart_driver __read_mostly pl011_driver = {
     .vuart_info   = pl011_vuart,
 };
 
-static int __init pl011_uart_init(int irq, u64 addr, u64 size)
+static int __init pl011_uart_init(int irq, u64 addr, u64 size, bool sbsa)
 {
     struct pl011 *uart;
 
@@ -225,6 +232,7 @@ static int __init pl011_uart_init(int irq, u64 addr, u64 size)
     uart->data_bits = 8;
     uart->parity    = PARITY_NONE;
     uart->stop_bits = 1;
+    uart->sbsa      = sbsa;
 
     uart->regs = ioremap_nocache(addr, size);
     if ( !uart->regs )
@@ -273,7 +281,7 @@ static int __init pl011_dt_uart_init(struct dt_device_node *dev,
         return -EINVAL;
     }
 
-    res = pl011_uart_init(res, addr, size);
+    res = pl011_uart_init(res, addr, size, false);
     if ( res < 0 )
     {
         printk("pl011: Unable to initialize\n");
@@ -304,6 +312,7 @@ static int __init pl011_acpi_uart_init(const void *data)
     acpi_status status;
     struct acpi_table_spcr *spcr = NULL;
     int res;
+    bool sbsa = false;
 
     status = acpi_get_table(ACPI_SIG_SPCR, 0,
                             (struct acpi_table_header **)&spcr);
@@ -314,11 +323,15 @@ static int __init pl011_acpi_uart_init(const void *data)
         return -EINVAL;
     }
 
+    if ( (spcr->interface_type == ACPI_DBG2_SBSA) ||
+         (spcr->interface_type == ACPI_DBG2_SBSA_32) )
+        sbsa = true;
+
     /* trigger/polarity information is not available in spcr */
     irq_set_type(spcr->interrupt, IRQ_TYPE_LEVEL_HIGH);
 
     res = pl011_uart_init(spcr->interrupt, spcr->serial_port.address,
-                          PAGE_SIZE);
+                          PAGE_SIZE, sbsa);
     if ( res < 0 )
     {
         printk("pl011: Unable to initialize\n");
@@ -332,6 +345,17 @@ ACPI_DEVICE_START(apl011, "PL011 UART", DEVICE_SERIAL)
         .class_type = ACPI_DBG2_PL011,
         .init = pl011_acpi_uart_init,
 ACPI_DEVICE_END
+
+ACPI_DEVICE_START(asbsa_uart, "SBSA UART", DEVICE_SERIAL)
+    .class_type = ACPI_DBG2_SBSA,
+    .init = pl011_acpi_uart_init,
+ACPI_DEVICE_END
+
+ACPI_DEVICE_START(asbsa32_uart, "SBSA32 UART", DEVICE_SERIAL)
+    .class_type = ACPI_DBG2_SBSA_32,
+    .init = pl011_acpi_uart_init,
+ACPI_DEVICE_END
+
 #endif
 
 /*
-- 
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc. 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, 
a Linux Foundation Collaborative Project


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      parent reply	other threads:[~2016-06-07 19:04 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-07 19:04 [PATCH V7 1/3] drivers/pl011: Don't configure baudrate Shanker Donthineni
2016-06-07 19:04 ` [PATCH V7 2/3] drivers/pl011: Use combination of UARTRIS and UARTMSC instead of UARTMIS Shanker Donthineni
2016-06-08  9:06   ` Julien Grall
2016-06-07 19:04 ` Shanker Donthineni [this message]

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