[Xen-devel] [PATCH V4 2/3] drivers/pl011: Use combination of UARTRIS and UARTMSC instead of UARTMIS

[Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>]

The Masked interrupt status register (UARTMIS) is not described in ARM
SBSA 2.x document. Anding of two registers UARTMSC and UARTRIS values
gives the same information as register UARTMIS.

UARTRIS, UARTMSC and UARTMIS definitions are found in PrimeCell UART
PL011 (Revision: r1p4).
 - 3.3.10 Interrupt mask set/clear register, UARTIMSC
 - 3.3.11 Raw interrupt status register, UARTRIS
 - 3.3.12 Masked interrupt status register, UARTMIS

This this necessary for driver to be SBSA compliant v2.x without
afftecting the current driver functionality.

Signed-off-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>
---
 xen/drivers/char/pl011.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/char/pl011.c b/xen/drivers/char/pl011.c
index 6a3c21b..755a965 100644
--- a/xen/drivers/char/pl011.c
+++ b/xen/drivers/char/pl011.c
@@ -57,7 +57,10 @@ static void pl011_interrupt(int irq, void *data, struct 
cpu_user_regs *regs)
 {
     struct serial_port *port = data;
     struct pl011 *uart = port->uart;
-    unsigned int status = pl011_read(uart, MIS);
+    unsigned int status;
+
+    /* UARTMIS is not documented in SBSA v2.x, so using UARTRIS/UARTIMSC */
+    status = pl011_read(uart, RIS) & pl011_read(uart, IMSC);
 
     if ( status )
     {
@@ -76,7 +79,7 @@ static void pl011_interrupt(int irq, void *data, struct 
cpu_user_regs *regs)
             if ( status & (TXI) )
                 serial_tx_interrupt(port, regs);
 
-            status = pl011_read(uart, MIS);
+            status = pl011_read(uart, RIS) & pl011_read(uart, IMSC);
         } while (status != 0);
     }
 }
-- 
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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