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Message-Id: <d99f90e2107d7bff3adc187b5ce36a79cc786bfd.1558527014.git.christophe.leroy@c-s.fr>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Subject: [PATCH] tty: serial: cpm_uart - fix init when SMC is relocated
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.com>
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-serial@vger.kernel.org
Date:   Wed, 22 May 2019 12:17:11 +0000 (UTC)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

SMC relocation can also be activated earlier by the bootloader,
so the driver's behaviour cannot rely on selected kernel config.

When the SMC is relocated, CPM_CR_INIT_TRX cannot be used.

But the only thing CPM_CR_INIT_TRX does is to clear the
rstate and tstate registers, so this can be done manually,
even when SMC is not relocated.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Fixes: 9ab921201444 ("cpm_uart: fix non-console port startup bug")
---
 drivers/tty/serial/cpm_uart/cpm_uart_core.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/cpm_uart/cpm_uart_core.c b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
index b929c7ae3a27..7bab9a3eda92 100644
--- a/drivers/tty/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
@@ -407,7 +407,16 @@ static int cpm_uart_startup(struct uart_port *port)
 			clrbits16(&pinfo->sccp->scc_sccm, UART_SCCM_RX);
 		}
 		cpm_uart_initbd(pinfo);
-		cpm_line_cr_cmd(pinfo, CPM_CR_INIT_TRX);
+		if (IS_SMC(pinfo)) {
+			out_be32(&pinfo->smcup->smc_rstate, 0);
+			out_be32(&pinfo->smcup->smc_tstate, 0);
+			out_be16(&pinfo->smcup->smc_rbptr,
+				 in_be16(&pinfo->smcup->smc_rbase));
+			out_be16(&pinfo->smcup->smc_tbptr,
+				 in_be16(&pinfo->smcup->smc_tbase));
+		} else {
+			cpm_line_cr_cmd(pinfo, CPM_CR_INIT_TRX);
+		}
 	}
 	/* Install interrupt handler. */
 	retval = request_irq(port->irq, cpm_uart_int, 0, "cpm_uart", port);
@@ -861,16 +870,14 @@ static void cpm_uart_init_smc(struct uart_cpm_port *pinfo)
 	         (u8 __iomem *)pinfo->tx_bd_base - DPRAM_BASE);
 
 /*
- *  In case SMC1 is being relocated...
+ *  In case SMC is being relocated...
  */
-#if defined (CONFIG_I2C_SPI_SMC1_UCODE_PATCH)
 	out_be16(&up->smc_rbptr, in_be16(&pinfo->smcup->smc_rbase));
 	out_be16(&up->smc_tbptr, in_be16(&pinfo->smcup->smc_tbase));
 	out_be32(&up->smc_rstate, 0);
 	out_be32(&up->smc_tstate, 0);
 	out_be16(&up->smc_brkcr, 1);              /* number of break chars */
 	out_be16(&up->smc_brkec, 0);
-#endif
 
 	/* Set up the uart parameters in the
 	 * parameter ram.
@@ -884,8 +891,6 @@ static void cpm_uart_init_smc(struct uart_cpm_port *pinfo)
 	out_be16(&up->smc_brkec, 0);
 	out_be16(&up->smc_brkcr, 1);
 
-	cpm_line_cr_cmd(pinfo, CPM_CR_INIT_TRX);
-
 	/* Set UART mode, 8 bit, no parity, one stop.
 	 * Enable receive and transmit.
 	 */
-- 
2.13.3