Re: [U-Boot] [PATCH 1/2] mxc_ocotp: Do not disable the OCOTP clock after every access

Hi Fabio,

On Tue, Nov 25, 2014 at 4:11 PM, Fabio Estevam fabio.estevam@freescale.com wrote:

Leave the OCOTP turned on, so that we subsequent access do not fail.

After enabling the thermal driver on a mx6sxsabresd board:

U-Boot 2015.01-rc1-18267-g99d4189-dirty (Nov 24 2014 - 12:59:01)

CPU: Freescale i.MX6SX rev1.0 at 792 MHz CPU: Temperature 48 C Reset cause: POR Board: MX6SX SABRE SDB I2C: ready DRAM: 1 GiB PMIC: PFUZE100 ID=0x10 MMC: FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2 00:01.0 - 16c3:abcd - Bridge device 01:00.0 - 8086:08b1 - Network controller In: serial Out: serial Err: serial Net: (hang)

As the thermal driver accesses the ocotp registers, its clock will be disabled afterwards.

Then when the MAC address is read (also from ocotp registers) it will cause a hang.

Do not disable the ocotp clock to prevent this problem.

Signed-off-by: Fabio Estevam fabio.estevam@freescale.com

drivers/misc/mxc_ocotp.c | 2 -- 1 file changed, 2 deletions(-)

diff --git a/drivers/misc/mxc_ocotp.c b/drivers/misc/mxc_ocotp.c index 3de1245..67f9429 100644 --- a/drivers/misc/mxc_ocotp.c +++ b/drivers/misc/mxc_ocotp.c @@ -81,8 +81,6 @@ static int finish_access(struct ocotp_regs *regs, const char *caller) err = !!(readl(&regs->ctrl) & BM_CTRL_ERROR); clear_error(regs);

•   enable_ocotp_clk(0);
  

•   if (err) {
            printf("mxc_ocotp %s(): Access protect error\n", caller);
            return -EIO;
  

That, or: - Make imx_get_mac_from_fuse() call enable_ocotp_clk(1) before reading the fuses, then call enable_ocotp_clk(0). - Make enable_ocotp_clk() return the clock initial state and store it in prepare_access(), then restore it in finish_access(). Same in imx_get_mac_from_fuse().

Which of these 3 choices do you think would be the best?

Regards, Benoît