From 6b4b8fc87dc5cbfcfb5c749dc200906471fb854c Mon Sep 17 00:00:00 2001 From: Qiang Liu Date: Wed, 15 Feb 2012 15:40:34 +0800 Subject: [PATCH] sata_fsl: add support for interrupt coalsecing feature Adds support for interrupt coalescing feature to reduce interrupt events. Provides a mechanism of adjusting coalescing count and timeout tick by sysfs at runtime, so that tradeoff of latency and CPU load can be made depending on different applications. Signed-off-by: Qiang Liu Signed-off-by: Jeff Garzik --- drivers/ata/sata_fsl.c | 111 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 107 insertions(+), 4 deletions(-) diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c index 0120b0d1e9a5..d6577b93bee3 100644 --- a/drivers/ata/sata_fsl.c +++ b/drivers/ata/sata_fsl.c @@ -6,7 +6,7 @@ * Author: Ashish Kalra * Li Yang * - * Copyright (c) 2006-2007, 2011 Freescale Semiconductor, Inc. + * Copyright (c) 2006-2007, 2011-2012 Freescale Semiconductor, Inc. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the @@ -26,6 +26,15 @@ #include #include +static unsigned int intr_coalescing_count; +module_param(intr_coalescing_count, int, S_IRUGO); +MODULE_PARM_DESC(intr_coalescing_count, + "INT coalescing count threshold (1..31)"); + +static unsigned int intr_coalescing_ticks; +module_param(intr_coalescing_ticks, int, S_IRUGO); +MODULE_PARM_DESC(intr_coalescing_ticks, + "INT coalescing timer threshold in AHB ticks"); /* Controller information */ enum { SATA_FSL_QUEUE_DEPTH = 16, @@ -82,6 +91,16 @@ enum { SATA_FSL_IRQ_FLAG = IRQF_SHARED, }; +/* + * Interrupt Coalescing Control Register bitdefs */ +enum { + ICC_MIN_INT_COUNT_THRESHOLD = 1, + ICC_MAX_INT_COUNT_THRESHOLD = ((1 << 5) - 1), + ICC_MIN_INT_TICKS_THRESHOLD = 0, + ICC_MAX_INT_TICKS_THRESHOLD = ((1 << 19) - 1), + ICC_SAFE_INT_TICKS = 1, +}; + /* * Host Controller command register set - per port */ @@ -263,8 +282,65 @@ struct sata_fsl_host_priv { void __iomem *csr_base; int irq; int data_snoop; + struct device_attribute intr_coalescing; }; +static void fsl_sata_set_irq_coalescing(struct ata_host *host, + unsigned int count, unsigned int ticks) +{ + struct sata_fsl_host_priv *host_priv = host->private_data; + void __iomem *hcr_base = host_priv->hcr_base; + + if (count > ICC_MAX_INT_COUNT_THRESHOLD) + count = ICC_MAX_INT_COUNT_THRESHOLD; + else if (count < ICC_MIN_INT_COUNT_THRESHOLD) + count = ICC_MIN_INT_COUNT_THRESHOLD; + + if (ticks > ICC_MAX_INT_TICKS_THRESHOLD) + ticks = ICC_MAX_INT_TICKS_THRESHOLD; + else if ((ICC_MIN_INT_TICKS_THRESHOLD == ticks) && + (count > ICC_MIN_INT_COUNT_THRESHOLD)) + ticks = ICC_SAFE_INT_TICKS; + + spin_lock(&host->lock); + iowrite32((count << 24 | ticks), hcr_base + ICC); + + intr_coalescing_count = count; + intr_coalescing_ticks = ticks; + spin_unlock(&host->lock); + + DPRINTK("intrrupt coalescing, count = 0x%x, ticks = %x\n", + intr_coalescing_count, intr_coalescing_ticks); + DPRINTK("ICC register status: (hcr base: 0x%x) = 0x%x\n", + hcr_base, ioread32(hcr_base + ICC)); +} + +static ssize_t fsl_sata_intr_coalescing_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d %d\n", + intr_coalescing_count, intr_coalescing_ticks); +} + +static ssize_t fsl_sata_intr_coalescing_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + unsigned int coalescing_count, coalescing_ticks; + + if (sscanf(buf, "%d%d", + &coalescing_count, + &coalescing_ticks) != 2) { + printk(KERN_ERR "fsl-sata: wrong parameter format.\n"); + return -EINVAL; + } + + fsl_sata_set_irq_coalescing(dev_get_drvdata(dev), + coalescing_count, coalescing_ticks); + + return strlen(buf); +} + static inline unsigned int sata_fsl_tag(unsigned int tag, void __iomem *hcr_base) { @@ -346,10 +422,10 @@ static unsigned int sata_fsl_fill_sg(struct ata_queued_cmd *qc, void *cmd_desc, (unsigned long long)sg_addr, sg_len); /* warn if each s/g element is not dword aligned */ - if (sg_addr & 0x03) + if (unlikely(sg_addr & 0x03)) ata_port_err(qc->ap, "s/g addr unaligned : 0x%llx\n", (unsigned long long)sg_addr); - if (sg_len & 0x03) + if (unlikely(sg_len & 0x03)) ata_port_err(qc->ap, "s/g len unaligned : 0x%x\n", sg_len); @@ -1245,6 +1321,13 @@ static int sata_fsl_init_controller(struct ata_host *host) iowrite32(0x00000FFFF, hcr_base + CE); iowrite32(0x00000FFFF, hcr_base + DE); + /* + * reset the number of command complete bits which will cause the + * interrupt to be signaled + */ + fsl_sata_set_irq_coalescing(host, intr_coalescing_count, + intr_coalescing_ticks); + /* * host controller will be brought on-line, during xx_port_start() * callback, that should also initiate the OOB, COMINIT sequence @@ -1309,7 +1392,7 @@ static int sata_fsl_probe(struct platform_device *ofdev) void __iomem *csr_base = NULL; struct sata_fsl_host_priv *host_priv = NULL; int irq; - struct ata_host *host; + struct ata_host *host = NULL; u32 temp; struct ata_port_info pi = sata_fsl_port_info[0]; @@ -1356,6 +1439,10 @@ static int sata_fsl_probe(struct platform_device *ofdev) /* allocate host structure */ host = ata_host_alloc_pinfo(&ofdev->dev, ppi, SATA_FSL_MAX_PORTS); + if (!host) { + retval = -ENOMEM; + goto error_exit_with_cleanup; + } /* host->iomap is not used currently */ host->private_data = host_priv; @@ -1373,10 +1460,24 @@ static int sata_fsl_probe(struct platform_device *ofdev) dev_set_drvdata(&ofdev->dev, host); + host_priv->intr_coalescing.show = fsl_sata_intr_coalescing_show; + host_priv->intr_coalescing.store = fsl_sata_intr_coalescing_store; + sysfs_attr_init(&host_priv->intr_coalescing.attr); + host_priv->intr_coalescing.attr.name = "intr_coalescing"; + host_priv->intr_coalescing.attr.mode = S_IRUGO | S_IWUSR; + retval = device_create_file(host->dev, &host_priv->intr_coalescing); + if (retval) + goto error_exit_with_cleanup; + return 0; error_exit_with_cleanup: + if (host) { + dev_set_drvdata(&ofdev->dev, NULL); + ata_host_detach(host); + } + if (hcr_base) iounmap(hcr_base); if (host_priv) @@ -1390,6 +1491,8 @@ static int sata_fsl_remove(struct platform_device *ofdev) struct ata_host *host = dev_get_drvdata(&ofdev->dev); struct sata_fsl_host_priv *host_priv = host->private_data; + device_remove_file(&ofdev->dev, &host_priv->intr_coalescing); + ata_host_detach(host); dev_set_drvdata(&ofdev->dev, NULL);