[PATCH 2/2] omap: serial: fix non-empty rx uart fifo abort

[PATCH 2/2] omap: serial: fix non-empty rx uart fifo abort

[Vikram Pandita]

Empty uart rx fifo read can cause omap to abort
OMAP silicon affected: OMAP3630, OMAP4430
OMAP silicon not-affected: omap1/2/3

So pass flag UPF_NO_EMPTY_FIFO_READ in plat_serial8250_port, so that 8250
driver does not abort on empty rx fifo read

Tested on zoom3(3630) board

Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
---
 arch/arm/mach-omap2/serial.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 2e17b57..669652b 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -624,8 +624,15 @@ void __init omap_serial_early_init(void)
 		uart->p = p;
 		list_add_tail(&uart->node, &uart_list);
 
-		if (cpu_is_omap44xx())
+		if (cpu_is_omap44xx()) {
 			p->irq += 32;
+			/* Do not read empty UART fifo on omap4 */
+			p->flags |= UPF_NO_EMPTY_FIFO_READ;
+		}
+
+		/* Do not read empty UART fifo on omap3630 */
+		if (cpu_is_omap3630())
+			p->flags |= UPF_NO_EMPTY_FIFO_READ;
 
 		omap_uart_enable_clocks(uart);
 	}
-- 
1.6.5.1.69.g36942

Re: [PATCH 2/2] omap: serial: fix non-empty rx uart fifo abort

[Tony Lindgren]

* Vikram Pandita <vikram.pandita@ti.com> [091116 15:00]:
> Empty uart rx fifo read can cause omap to abort
> OMAP silicon affected: OMAP3630, OMAP4430
> OMAP silicon not-affected: omap1/2/3
> 
> So pass flag UPF_NO_EMPTY_FIFO_READ in plat_serial8250_port, so that 8250
> driver does not abort on empty rx fifo read
> 
> Tested on zoom3(3630) board

This too as it depends on the 1/2 patch.

Tony
 
> Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
> ---
>  arch/arm/mach-omap2/serial.c |    9 ++++++++-
>  1 files changed, 8 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
> index 2e17b57..669652b 100644
> --- a/arch/arm/mach-omap2/serial.c
> +++ b/arch/arm/mach-omap2/serial.c
> @@ -624,8 +624,15 @@ void __init omap_serial_early_init(void)
>  		uart->p = p;
>  		list_add_tail(&uart->node, &uart_list);
>  
> -		if (cpu_is_omap44xx())
> +		if (cpu_is_omap44xx()) {
>  			p->irq += 32;
> +			/* Do not read empty UART fifo on omap4 */
> +			p->flags |= UPF_NO_EMPTY_FIFO_READ;
> +		}
> +
> +		/* Do not read empty UART fifo on omap3630 */
> +		if (cpu_is_omap3630())
> +			p->flags |= UPF_NO_EMPTY_FIFO_READ;
>  
>  		omap_uart_enable_clocks(uart);
>  	}
> -- 
> 1.6.5.1.69.g36942
> 
> --
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[PATCH 2/2] omap: serial: fix non-empty rx uart fifo abort

[Vikram Pandita]

OMAP3630 and OMAP4430 UART IP blocks have a restriction wrt RX FIFO.
Empty RX fifo read causes an abort. OMAP1/2/3 do not have this restriction.

so pass the flag UPF_NO_EMPTY_FIFO_READ in plat_serial8250_port, so that 8250
driver does not abort on empty rx fifo read

tested on zoom3(3630) board

Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
---
 arch/arm/mach-omap2/serial.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 2e17b57..669652b 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -624,8 +624,15 @@ void __init omap_serial_early_init(void)
 		uart->p = p;
 		list_add_tail(&uart->node, &uart_list);
 
-		if (cpu_is_omap44xx())
+		if (cpu_is_omap44xx()) {
 			p->irq += 32;
+			/* Do not read empty UART fifo on omap4 */
+			p->flags |= UPF_NO_EMPTY_FIFO_READ;
+		}
+
+		/* Do not read empty UART fifo on omap3630 */
+		if (cpu_is_omap3630())
+			p->flags |= UPF_NO_EMPTY_FIFO_READ;
 
 		omap_uart_enable_clocks(uart);
 	}
-- 
1.6.5.1.69.g36942