From patchwork Tue Feb 17 19:03:51 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mugunthan V N X-Patchwork-Id: 5841001 Return-Path: X-Original-To: patchwork-linux-spi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 6969BBF440 for ; Tue, 17 Feb 2015 19:04:01 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9A83320211 for ; Tue, 17 Feb 2015 19:04:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BA0C2201F2 for ; Tue, 17 Feb 2015 19:03:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751749AbbBQTD7 (ORCPT ); Tue, 17 Feb 2015 14:03:59 -0500 Received: from devils.ext.ti.com ([198.47.26.153]:41530 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751587AbbBQTD6 (ORCPT ); Tue, 17 Feb 2015 14:03:58 -0500 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by devils.ext.ti.com (8.13.7/8.13.7) with ESMTP id t1HJ3tsm020734; Tue, 17 Feb 2015 13:03:55 -0600 Received: from DLEE71.ent.ti.com (dlee71.ent.ti.com [157.170.170.114]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id t1HJ3sj5031967; Tue, 17 Feb 2015 13:03:54 -0600 Received: from dlep32.itg.ti.com (157.170.170.100) by DLEE71.ent.ti.com (157.170.170.114) with Microsoft SMTP Server id 14.3.224.2; Tue, 17 Feb 2015 13:03:54 -0600 Received: from mugunthan-lt.itg.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep32.itg.ti.com (8.14.3/8.13.8) with ESMTP id t1HJ3q21021397; Tue, 17 Feb 2015 13:03:52 -0600 From: Mugunthan V N To: CC: , , Mugunthan V N Subject: [PATCH 1/1] drivers: spi: ti-qspi: wait for busy bit clear before data write/read Date: Wed, 18 Feb 2015 00:33:51 +0530 Message-ID: <1424199831-5518-1-git-send-email-mugunthanvnm@ti.com> X-Mailer: git-send-email 2.2.1.62.g3f15098 MIME-Version: 1.0 Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Data corruption is seen while reading/writing large data from/to qspi device because the data register is over written or read before data is ready which is denoted by busy bit in status register. SO adding a busy bit check before writing/reading data to/from qspi device. Signed-off-by: Mugunthan V N --- drivers/spi/spi-ti-qspi.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c index 884a716..5c06168 100644 --- a/drivers/spi/spi-ti-qspi.c +++ b/drivers/spi/spi-ti-qspi.c @@ -101,6 +101,7 @@ struct ti_qspi { #define QSPI_FLEN(n) ((n - 1) << 0) /* STATUS REGISTER */ +#define BUSY 0x01 #define WC 0x02 /* INTERRUPT REGISTER */ @@ -199,6 +200,21 @@ static void ti_qspi_restore_ctx(struct ti_qspi *qspi) ti_qspi_write(qspi, ctx_reg->clkctrl, QSPI_SPI_CLOCK_CNTRL_REG); } +static inline u32 qspi_is_busy(struct ti_qspi *qspi) +{ + u32 stat; + unsigned long timeout = jiffies + QSPI_COMPLETION_TIMEOUT; + + stat = ti_qspi_read(qspi, QSPI_SPI_STATUS_REG); + while ((stat & BUSY) && time_after(timeout, jiffies)) { + cpu_relax(); + stat = ti_qspi_read(qspi, QSPI_SPI_STATUS_REG); + } + + WARN(stat & BUSY, "qspi busy\n"); + return stat & BUSY; +} + static int qspi_write_msg(struct ti_qspi *qspi, struct spi_transfer *t) { int wlen, count; @@ -211,6 +227,9 @@ static int qspi_write_msg(struct ti_qspi *qspi, struct spi_transfer *t) wlen = t->bits_per_word >> 3; /* in bytes */ while (count) { + if (qspi_is_busy(qspi)) + return -EBUSY; + switch (wlen) { case 1: dev_dbg(qspi->dev, "tx cmd %08x dc %08x data %02x\n", @@ -266,6 +285,9 @@ static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t) while (count) { dev_dbg(qspi->dev, "rx cmd %08x dc %08x\n", cmd, qspi->dc); + if (qspi_is_busy(qspi)) + return -EBUSY; + ti_qspi_write(qspi, cmd, QSPI_SPI_CMD_REG); if (!wait_for_completion_timeout(&qspi->transfer_complete, QSPI_COMPLETION_TIMEOUT)) {