Hi Akshay

On Thu, Mar 21, 2013 at 11:33 PM, Akshay Saraswat akshay.s@samsung.comwrote:

This patch enables the uart tx/rx fifo. Now that fifo is enabled, the uart read/write functions are modfied to check the UFSTAT register for fifo status instead of UTRSTAT (as required with fifo's enabled). Tested by booting linux kernel. Before enabling tx/rx fifo "Uncompressing linux" message is garbled and after enabling it is proper.

Is this because Linux enables the FIFOs?

Anyway this seems fine to me, but I have a question below.

Signed-off-by: Alim Akhtar alim.akhtar@samsung.com Signed-off-by: Akshay Saraswat akshay.s@samsung.com

---

drivers/serial/serial_s5p.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/serial/serial_s5p.c b/drivers/serial/serial_s5p.c index 3c41242..e65125c 100644 --- a/drivers/serial/serial_s5p.c +++ b/drivers/serial/serial_s5p.c @@ -30,6 +30,10 @@

DECLARE_GLOBAL_DATA_PTR;

+#define RX_FIFO_COUNT_MASK 0xff +#define RX_FIFO_FULL_MASK (1 << 8) +#define TX_FIFO_FULL_MASK (1 << 24)

static inline struct s5p_uart *s5p_get_base_uart(int dev_index) { u32 offset = dev_index * sizeof(struct s5p_uart); @@ -87,8 +91,8 @@ int serial_init_dev(const int dev_index) { struct s5p_uart *const uart = s5p_get_base_uart(dev_index);

•   /* reset and enable FIFOs, set triggers to the maximum */
  

•   writel(0, &uart->ufcon);
  

•   /* enable FIFOs */
  

•   writel(0x1, &uart->ufcon);
  
  

It is odd that you seem to be saying that the old code did not enable FIFOs, but this code does? Or should you update your comment?

    writel(0, &uart->umcon);
    /* 8N1 */
    writel(0x3, &uart->ulcon);

@@ -130,7 +134,8 @@ int serial_getc_dev(const int dev_index) struct s5p_uart *const uart = s5p_get_base_uart(dev_index);

    /* wait for character to arrive */

•   while (!(readl(&uart->utrstat) & 0x1)) {
  

•   while (!(readl(&uart->ufstat) & (RX_FIFO_COUNT_MASK |
  

•                                    RX_FIFO_FULL_MASK))) {
            if (serial_err_check(dev_index, 0))
                    return 0;
    }
  

@@ -146,7 +151,7 @@ void serial_putc_dev(const char c, const int dev_index) struct s5p_uart *const uart = s5p_get_base_uart(dev_index);

    /* wait for room in the tx FIFO */

•   while (!(readl(&uart->utrstat) & 0x2)) {
  

•   while ((readl(&uart->ufstat) & TX_FIFO_FULL_MASK)) {
            if (serial_err_check(dev_index, 1))
                    return;
    }
  

-- 1.8.0

Regards, Simon