Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759915AbYJEQ1o (ORCPT ); Sun, 5 Oct 2008 12:27:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756109AbYJEQWk (ORCPT ); Sun, 5 Oct 2008 12:22:40 -0400 Received: from smtpeu1.atmel.com ([195.65.72.27]:62761 "EHLO bagnes.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758198AbYJEQWi (ORCPT ); Sun, 5 Oct 2008 12:22:38 -0400 From: Haavard Skinnemoen To: Pierre Ossman Cc: kernel@avr32linux.org, linux-kernel@vger.kernel.org, Haavard Skinnemoen Subject: [PATCH v2 1/7] atmel-mci: Implement tasklet as a state machine Date: Sun, 5 Oct 2008 18:21:24 +0200 Message-Id: <1223223690-2637-2-git-send-email-haavard.skinnemoen@atmel.com> X-Mailer: git-send-email 1.5.6.5 In-Reply-To: <1223223690-2637-1-git-send-email-haavard.skinnemoen@atmel.com> References: <1223223690-2637-1-git-send-email-haavard.skinnemoen@atmel.com> X-OriginalArrivalTime: 05 Oct 2008 16:21:15.0103 (UTC) FILETIME=[639906F0:01C92706] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 11836 Lines: 401 With the current system of completed/pending events, things may get handled in different order depending on which event triggers first. For example, if the data transfer is complete before the command, the stop command must be sent after the command is complete, not the data. This creates a bit of complexity around the stop command. By having the tasklet go through a sequence of clearly defined states, things always happen in a certain order even if the events come at different times, so the stop command can simply be sent when we exit the "sending data" state because we will never enter that state before the command has been sent successfully. Signed-off-by: Haavard Skinnemoen --- drivers/mmc/host/atmel-mci.c | 249 ++++++++++++++++++++++++------------------ 1 files changed, 145 insertions(+), 104 deletions(-) diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c index 0000896..d834e37 100644 --- a/drivers/mmc/host/atmel-mci.c +++ b/drivers/mmc/host/atmel-mci.c @@ -36,11 +36,17 @@ enum { EVENT_CMD_COMPLETE = 0, - EVENT_DATA_ERROR, - EVENT_DATA_COMPLETE, - EVENT_STOP_SENT, - EVENT_STOP_COMPLETE, EVENT_XFER_COMPLETE, + EVENT_DATA_COMPLETE, + EVENT_DATA_ERROR, +}; + +enum atmel_mci_state { + STATE_SENDING_CMD = 0, + STATE_SENDING_DATA, + STATE_DATA_BUSY, + STATE_SENDING_STOP, + STATE_DATA_ERROR, }; struct atmel_mci { @@ -56,7 +62,6 @@ struct atmel_mci { u32 cmd_status; u32 data_status; - u32 stop_status; u32 stop_cmdr; u32 mode_reg; @@ -65,6 +70,7 @@ struct atmel_mci { struct tasklet_struct tasklet; unsigned long pending_events; unsigned long completed_events; + enum atmel_mci_state state; int present; int detect_pin; @@ -79,18 +85,12 @@ struct atmel_mci { struct platform_device *pdev; }; -#define atmci_is_completed(host, event) \ - test_bit(event, &host->completed_events) #define atmci_test_and_clear_pending(host, event) \ test_and_clear_bit(event, &host->pending_events) -#define atmci_test_and_set_completed(host, event) \ - test_and_set_bit(event, &host->completed_events) #define atmci_set_completed(host, event) \ set_bit(event, &host->completed_events) #define atmci_set_pending(host, event) \ set_bit(event, &host->pending_events) -#define atmci_clear_pending(host, event) \ - clear_bit(event, &host->pending_events) /* * The debugfs stuff below is mostly optimized away when @@ -258,6 +258,10 @@ static void atmci_init_debugfs(struct atmel_mci *host) if (!node) goto err; + node = debugfs_create_u32("state", S_IRUSR, root, (u32 *)&host->state); + if (!node) + goto err; + node = debugfs_create_x32("pending_events", S_IRUSR, root, (u32 *)&host->pending_events); if (!node) @@ -378,8 +382,6 @@ static void atmci_start_command(struct atmel_mci *host, struct mmc_command *cmd, u32 cmd_flags) { - /* Must read host->cmd after testing event flags */ - smp_rmb(); WARN_ON(host->cmd); host->cmd = cmd; @@ -472,6 +474,7 @@ static void atmci_request(struct mmc_host *mmc, struct mmc_request *mrq) host->mrq = mrq; host->pending_events = 0; host->completed_events = 0; + host->state = STATE_SENDING_CMD; atmci_enable(host); @@ -596,8 +599,10 @@ static struct mmc_host_ops atmci_ops = { }; static void atmci_command_complete(struct atmel_mci *host, - struct mmc_command *cmd, u32 status) + struct mmc_command *cmd) { + u32 status = host->cmd_status; + /* Read the response from the card (up to 16 bytes) */ cmd->resp[0] = mci_readl(host, RSPR); cmd->resp[1] = mci_readl(host, RSPR); @@ -666,20 +671,32 @@ static void atmci_detect_change(unsigned long data) * commands or data transfers. */ mci_writel(host, CR, MCI_CR_SWRST); + mci_readl(host, SR); - if (!atmci_is_completed(host, EVENT_CMD_COMPLETE)) - mrq->cmd->error = -ENOMEDIUM; + host->data = NULL; + host->cmd = NULL; - if (mrq->data && !atmci_is_completed(host, - EVENT_DATA_COMPLETE)) { - host->data = NULL; + switch (host->state) { + case STATE_SENDING_CMD: + mrq->cmd->error = -ENOMEDIUM; + if (!mrq->data) + break; + /* fall through */ + case STATE_SENDING_DATA: mrq->data->error = -ENOMEDIUM; - } - if (mrq->stop && !atmci_is_completed(host, - EVENT_STOP_COMPLETE)) + break; + case STATE_DATA_BUSY: + case STATE_DATA_ERROR: + if (mrq->data->error == -EINPROGRESS) + mrq->data->error = -ENOMEDIUM; + if (!mrq->stop) + break; + /* fall through */ + case STATE_SENDING_STOP: mrq->stop->error = -ENOMEDIUM; + break; + } - host->cmd = NULL; atmci_request_end(host->mmc, mrq); } @@ -693,81 +710,116 @@ static void atmci_tasklet_func(unsigned long priv) struct atmel_mci *host = mmc_priv(mmc); struct mmc_request *mrq = host->mrq; struct mmc_data *data = host->data; + struct mmc_command *cmd = host->cmd; + enum atmel_mci_state state = host->state; + enum atmel_mci_state prev_state; + u32 status; + + state = host->state; dev_vdbg(&mmc->class_dev, - "tasklet: pending/completed/mask %lx/%lx/%x\n", - host->pending_events, host->completed_events, + "tasklet: state %u pending/completed/mask %lx/%lx/%x\n", + state, host->pending_events, host->completed_events, mci_readl(host, IMR)); - if (atmci_test_and_clear_pending(host, EVENT_CMD_COMPLETE)) { - /* - * host->cmd must be set to NULL before the interrupt - * handler sees EVENT_CMD_COMPLETE - */ - host->cmd = NULL; - smp_wmb(); - atmci_set_completed(host, EVENT_CMD_COMPLETE); - atmci_command_complete(host, mrq->cmd, host->cmd_status); - - if (!mrq->cmd->error && mrq->stop - && atmci_is_completed(host, EVENT_XFER_COMPLETE) - && !atmci_test_and_set_completed(host, - EVENT_STOP_SENT)) - send_stop_cmd(host->mmc, mrq->data); - } - if (atmci_test_and_clear_pending(host, EVENT_STOP_COMPLETE)) { - /* - * host->cmd must be set to NULL before the interrupt - * handler sees EVENT_STOP_COMPLETE - */ - host->cmd = NULL; - smp_wmb(); - atmci_set_completed(host, EVENT_STOP_COMPLETE); - atmci_command_complete(host, mrq->stop, host->stop_status); - } - if (atmci_test_and_clear_pending(host, EVENT_DATA_ERROR)) { - u32 status = host->data_status; + do { + prev_state = state; - dev_vdbg(&mmc->class_dev, "data error: status=%08x\n", status); + switch (state) { + case STATE_SENDING_CMD: + if (!atmci_test_and_clear_pending(host, + EVENT_CMD_COMPLETE)) + break; - atmci_set_completed(host, EVENT_DATA_ERROR); - atmci_set_completed(host, EVENT_DATA_COMPLETE); + host->cmd = NULL; + atmci_set_completed(host, EVENT_CMD_COMPLETE); + atmci_command_complete(host, mrq->cmd); + if (!mrq->data || cmd->error) { + atmci_request_end(mmc, host->mrq); + break; + } - if (status & MCI_DTOE) { - dev_dbg(&mmc->class_dev, - "data timeout error\n"); - data->error = -ETIMEDOUT; - } else if (status & MCI_DCRCE) { - dev_dbg(&mmc->class_dev, "data CRC error\n"); - data->error = -EILSEQ; - } else { - dev_dbg(&mmc->class_dev, - "data FIFO error (status=%08x)\n", - status); - data->error = -EIO; - } + prev_state = state = STATE_SENDING_DATA; + /* fall through */ - if (host->present && data->stop - && atmci_is_completed(host, EVENT_CMD_COMPLETE) - && !atmci_test_and_set_completed( - host, EVENT_STOP_SENT)) - send_stop_cmd(host->mmc, data); + case STATE_SENDING_DATA: + if (atmci_test_and_clear_pending(host, + EVENT_DATA_ERROR)) { + if (data->stop) + send_stop_cmd(host->mmc, data); + state = STATE_DATA_ERROR; + break; + } - host->data = NULL; - } - if (atmci_test_and_clear_pending(host, EVENT_DATA_COMPLETE)) { - atmci_set_completed(host, EVENT_DATA_COMPLETE); + if (!atmci_test_and_clear_pending(host, + EVENT_XFER_COMPLETE)) + break; - if (!atmci_is_completed(host, EVENT_DATA_ERROR)) { - data->bytes_xfered = data->blocks * data->blksz; - data->error = 0; - } + atmci_set_completed(host, EVENT_XFER_COMPLETE); + prev_state = state = STATE_DATA_BUSY; + /* fall through */ - host->data = NULL; - } + case STATE_DATA_BUSY: + if (!atmci_test_and_clear_pending(host, + EVENT_DATA_COMPLETE)) + break; + + host->data = NULL; + atmci_set_completed(host, EVENT_DATA_COMPLETE); + status = host->data_status; + if (unlikely(status & ATMCI_DATA_ERROR_FLAGS)) { + if (status & MCI_DTOE) { + dev_dbg(&mmc->class_dev, + "data timeout error\n"); + data->error = -ETIMEDOUT; + } else if (status & MCI_DCRCE) { + dev_dbg(&mmc->class_dev, + "data CRC error\n"); + data->error = -EILSEQ; + } else { + dev_dbg(&mmc->class_dev, + "data FIFO error (status=%08x)\n", + status); + data->error = -EIO; + } + } else { + data->bytes_xfered = data->blocks * data->blksz; + data->error = 0; + } + + if (!data->stop) { + atmci_request_end(mmc, host->mrq); + prev_state = state; + break; + } - if (host->mrq && !host->cmd && !host->data) - atmci_request_end(mmc, host->mrq); + prev_state = state = STATE_SENDING_STOP; + if (!data->error) + send_stop_cmd(host->mmc, data); + /* fall through */ + + case STATE_SENDING_STOP: + if (!atmci_test_and_clear_pending(host, + EVENT_CMD_COMPLETE)) + break; + + host->cmd = NULL; + atmci_command_complete(host, mrq->stop); + atmci_request_end(mmc, host->mrq); + prev_state = state; + break; + + case STATE_DATA_ERROR: + if (!atmci_test_and_clear_pending(host, + EVENT_XFER_COMPLETE)) + break; + + state = STATE_DATA_BUSY; + break; + } + } while (state != prev_state); + + host->state = state; } static void atmci_read_data_pio(struct atmel_mci *host) @@ -832,10 +884,7 @@ done: mci_writel(host, IDR, MCI_RXRDY); mci_writel(host, IER, MCI_NOTBUSY); data->bytes_xfered += nbytes; - atmci_set_completed(host, EVENT_XFER_COMPLETE); - if (data->stop && atmci_is_completed(host, EVENT_CMD_COMPLETE) - && !atmci_test_and_set_completed(host, EVENT_STOP_SENT)) - send_stop_cmd(host->mmc, data); + atmci_set_pending(host, EVENT_XFER_COMPLETE); } static void atmci_write_data_pio(struct atmel_mci *host) @@ -903,10 +952,7 @@ done: mci_writel(host, IDR, MCI_TXRDY); mci_writel(host, IER, MCI_NOTBUSY); data->bytes_xfered += nbytes; - atmci_set_completed(host, EVENT_XFER_COMPLETE); - if (data->stop && atmci_is_completed(host, EVENT_CMD_COMPLETE) - && !atmci_test_and_set_completed(host, EVENT_STOP_SENT)) - send_stop_cmd(host->mmc, data); + atmci_set_pending(host, EVENT_XFER_COMPLETE); } static void atmci_cmd_interrupt(struct mmc_host *mmc, u32 status) @@ -915,14 +961,8 @@ static void atmci_cmd_interrupt(struct mmc_host *mmc, u32 status) mci_writel(host, IDR, MCI_CMDRDY); - if (atmci_is_completed(host, EVENT_STOP_SENT)) { - host->stop_status = status; - atmci_set_pending(host, EVENT_STOP_COMPLETE); - } else { - host->cmd_status = status; - atmci_set_pending(host, EVENT_CMD_COMPLETE); - } - + host->cmd_status = status; + atmci_set_pending(host, EVENT_CMD_COMPLETE); tasklet_schedule(&host->tasklet); } @@ -951,8 +991,9 @@ static irqreturn_t atmci_interrupt(int irq, void *dev_id) tasklet_schedule(&host->tasklet); } if (pending & MCI_NOTBUSY) { - mci_writel(host, IDR, (MCI_NOTBUSY - | ATMCI_DATA_ERROR_FLAGS)); + mci_writel(host, IDR, + ATMCI_DATA_ERROR_FLAGS | MCI_NOTBUSY); + host->data_status = status; atmci_set_pending(host, EVENT_DATA_COMPLETE); tasklet_schedule(&host->tasklet); } -- 1.5.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/