r4686 - developers/werner/wlan-spi/patches
werner at docs.openmoko.org
werner at docs.openmoko.org
Wed Oct 1 15:44:29 CEST 2008
Author: werner
Date: 2008-10-01 15:44:28 +0200 (Wed, 01 Oct 2008)
New Revision: 4686
Added:
developers/werner/wlan-spi/patches/hif-can-do-async.patch
developers/werner/wlan-spi/patches/hif-direct-interrupt.patch
Modified:
developers/werner/wlan-spi/patches/series
Log:
Use direct SPI interrupts and let the HIF handle asynchronous operations.
Added: developers/werner/wlan-spi/patches/hif-can-do-async.patch
===================================================================
--- developers/werner/wlan-spi/patches/hif-can-do-async.patch (rev 0)
+++ developers/werner/wlan-spi/patches/hif-can-do-async.patch 2008-10-01 13:44:28 UTC (rev 4686)
@@ -0,0 +1,20 @@
+After going to direct interrupts, our HIF can also handle asynchronous
+requests. Not entirely sure what kept them from working before. Most
+likely, there is some synchronization problem that we're now avoiding
+by also going through the system's main workqueue and thus implicitly
+synchronize with SPI.
+
+Index: korig/drivers/ar6000/hif/hif2.c
+===================================================================
+--- korig.orig/drivers/ar6000/hif/hif2.c 2008-10-01 09:34:27.000000000 -0300
++++ korig/drivers/ar6000/hif/hif2.c 2008-10-01 09:34:39.000000000 -0300
+@@ -282,8 +282,7 @@
+ mbs_cfg[i] = HIF_MBOX_START_ADDR(i);
+ break;
+ case HIF_DEVICE_GET_IRQ_PROC_MODE:
+- *ipm_cfg = HIF_DEVICE_IRQ_SYNC_ONLY;
+-// *ipm_cfg = HIF_DEVICE_IRQ_ASYNC_SYNC;
++ *ipm_cfg = HIF_DEVICE_IRQ_ASYNC_SYNC;
+ break;
+ default:
+ return A_ERROR;
Added: developers/werner/wlan-spi/patches/hif-direct-interrupt.patch
===================================================================
--- developers/werner/wlan-spi/patches/hif-direct-interrupt.patch (rev 0)
+++ developers/werner/wlan-spi/patches/hif-direct-interrupt.patch 2008-10-01 13:44:28 UTC (rev 4686)
@@ -0,0 +1,256 @@
+Proof-of-concept hack to directly use the interrupt coming from the card.
+
+The performance improvement isn't quite what I expected, only a meager
+4-5%, but perhaps more can be gained if we find a way to strip off some
+of the execution contexts. Right now, interrupts go through a workqueue,
+the AR6k driver, then the SDIO stack gets called from a kernel thread,
+and spi_bitbang uses a workqueue as well. It's almost surprising that we
+still get something done at all with those context switches.
+
+Index: korig/drivers/ar6000/hif/hif2.c
+===================================================================
+--- korig.orig/drivers/ar6000/hif/hif2.c 2008-10-01 09:34:08.000000000 -0300
++++ korig/drivers/ar6000/hif/hif2.c 2008-10-01 09:34:27.000000000 -0300
+@@ -21,9 +21,13 @@
+ #include <linux/list.h>
+ #include <linux/wait.h>
+ #include <linux/spinlock.h>
++#include <linux/irq.h>
++#include <linux/workqueue.h>
+ #include <linux/mmc/sdio_func.h>
+ #include <linux/mmc/sdio.h>
++
+ #include <asm/gpio.h>
++#include <asm/arch/regs-gpio.h>
+
+ #include "athdefs.h"
+ #include "a_types.h"
+@@ -59,6 +63,9 @@
+ void *htc_handle;
+ struct sdio_func *func;
+
++ int irq;
++ struct work_struct work;
++
+ /*
+ * @@@ our sweet little bit of bogosity - the mechanism that lets us
+ * use the SDIO stack from softirqs. This really wants to use skbs.
+@@ -99,6 +106,18 @@
+ }
+
+
++/*
++ * @@@ The slave select games below don't quite work, I think because SPI sets
++ * it to inactive _after_ telling its caller that the operation is complete
++ * (which it is, after all).
++ *
++ * Doing this properly will be a bit of fun, I suppose, because the SPI stack
++ * doesn't have the concept of briefly disabling slave select right before a
++ * transmission.
++ *
++ * For some yet unexplained reason, hacking the SPI driver isn't enough, and we
++ * need to force SS low with the s3c2410_gpio_setpin here.
++ */
+ static A_STATUS process_request(struct hif_request *req)
+ {
+ int ret;
+@@ -106,10 +125,12 @@
+
+ dev_dbg(&req->func->dev, "process_request(req %p)\n", req);
+ sdio_claim_host(req->func);
++ //s3c2410_gpio_setpin(S3C2410_GPG2, 1); /* raise SS */
+ if (req->read)
+ ret = req->read(req->func, req->buf, req->addr, req->len);
+ else
+ ret = req->write(req->func, req->addr, req->buf, req->len);
++ s3c2410_gpio_setpin(S3C2410_GPG2, 0); /* lower SS to allow interrupts */
+ sdio_release_host(req->func);
+ status = ret ? A_ERROR : A_OK;
+ if (req->completion)
+@@ -281,7 +302,7 @@
+
+ /* ========================================================================= */
+
+-#if 1
++#if 0
+
+ /*
+ * Volatile ought to be good enough to make gcc do the right thing on S3C24xx.
+@@ -396,69 +417,64 @@
+ /*
+ * The code below is for handling interrupts signalled out-of-band.
+ */
+-#if 0
+-#define IRQ_GPIO S3C2410_GPE8 /* SDDAT1 */
+-
+-
+-static atomic_t mask = ATOMIC_INIT(1);
++#if 1
+
+
+-static void sdio_ar6000_irq(struct sdio_func *func)
++static void sdio_ar6000_work(struct work_struct *work)
+ {
+- HIF_DEVICE *device = sdio_get_drvdata(func);
++ HIF_DEVICE *device = container_of(work, struct hif_device, work);
++ struct device *dev = HIFGetOSDevice(device);
++ A_STATUS status;
++
++ dev_dbg(dev, "sdio_ar6000_work-> %p\n", htcCallbacks.dsrHandler);
+
+- printk(KERN_DEBUG "sdio_ar6000_irq -> %p\n", htcCallbacks.dsrHandler);
+- BUG();
++ /* absorb the usual initial stray interrupt */
++ if (!device->htc_handle) {
++ HIFAckInterrupt(device);
++ return;
++ }
++ status = htcCallbacks.dsrHandler(device->htc_handle);
++ BUG_ON(status != A_OK);
+ }
+
+
+-static void sdio_ar6000_poll(void *context)
++static irqreturn_t sdio_ar6000_irq(int irq, void *arg)
+ {
+- HIF_DEVICE *device = context;
+- A_STATUS status;
++ HIF_DEVICE *device = arg;
++ struct device *dev = HIFGetOSDevice(device);
+
+- while (1) {
+- yield();
+- if (!gpio_get_value(IRQ_GPIO))
+- continue;
+- if (!atomic_add_unless(&mask, 1, 1))
+- continue;
+- status = htcCallbacks.dsrHandler(device->htc_handle);
+- BUG_ON(status != A_OK);
+- }
++ dev_dbg(dev, "sdio_ar6000_irq\n");
++ disable_irq(device->irq);
++ if (!schedule_work(&device->work))
++ dev_err(dev, "work already queued");
++ return IRQ_HANDLED;
+ }
+
+
+ void HIFAckInterrupt(HIF_DEVICE *device)
+ {
+ struct device *dev = HIFGetOSDevice(device);
+- int ret;
+
+- ret = atomic_dec_return(&mask);
+- BUG_ON(ret < 0);
+- dev_dbg(dev, "HIFAckInterrupt (%d)\n", ret);
++ dev_dbg(dev, "HIFAckInterrupt)\n");
++ enable_irq(device->irq);
+ }
+
+
+ void HIFUnMaskInterrupt(HIF_DEVICE *device)
+ {
+ struct device *dev = HIFGetOSDevice(device);
+- int ret;
+
+- ret = atomic_dec_return(&mask);
+- BUG_ON(ret < 0);
+- dev_dbg(dev, "HIFUnMaskInterrupt (%d)\n", ret);
++ dev_dbg(dev, "HIFUnMaskInterrupt)\n");
++ enable_irq(device->irq);
+ }
+
+
+ void HIFMaskInterrupt(HIF_DEVICE *device)
+ {
+ struct device *dev = HIFGetOSDevice(device);
+- int ret;
+
+- ret = atomic_inc_return(&mask);
+- BUG_ON(ret > 1);
+- dev_dbg(dev, "HIFMaskInterrupt (%d)\n", ret);
++ dev_dbg(dev, "HIFMaskInterrupt\n");
++ disable_irq(device->irq);
+ }
+ #endif
+
+@@ -506,7 +522,7 @@
+ struct device *dev = &func->dev;
+ int ret;
+ struct task_struct *task;
+-
++ u8 bus;
+
+ dev_dbg(dev, "sdio_ar6000_probe\n");
+ BUG_ON(!htcCallbacks.deviceInsertedHandler);
+@@ -524,11 +540,46 @@
+ dev_err(dev, "sdio_set_block_size returns %d\n", ret);
+ /* @@@ cleanup */
+ }
++#if 0
+ ret = sdio_claim_irq(func, sdio_ar6000_irq);
+ if (ret) {
+ dev_err(dev, "sdio_claim_irq returns %d\n", ret);
+ /* @@@ cleanup */
+ }
++#else
++ hif_device.irq = IRQ_EINT3;
++ INIT_WORK(&hif_device.work, sdio_ar6000_work);
++ ret = request_irq(hif_device.irq, sdio_ar6000_irq,
++ IRQF_TRIGGER_LOW, "ar6000", &hif_device);
++ if (ret) {
++ dev_err(dev, "request_irq returns %d\n", ret);
++ /* @@@ cleanup */
++ }
++ /* driver wants to be in charge for enabling the interrupt */
++ disable_irq(hif_device.irq);
++ bus = sdio_f0_readb(func, SDIO_CCCR_IF, &ret);
++ if (ret) {
++ dev_err(dev, "sdio_f0_readb(SDIO_CCCR_IF) returns %d\n",
++ ret);
++ /* @@@ cleanup */
++ }
++ printk(KERN_INFO "bus 0x%02x\n", bus);
++ /* try to set ECSI. Note: SCSI is 0, so this probably has no effect. */
++ bus |= 0x20;
++ sdio_f0_writeb(func, bus, SDIO_CCCR_IF, &ret);
++ if (ret) {
++ dev_err(dev, "sdio_f0_writeb(SDIO_CCCR_IF) returns %d\n",
++ ret);
++ /* @@@ cleanup */
++ }
++ sdio_f0_writeb(func, 3, SDIO_CCCR_IENx, &ret);
++ if (ret) {
++ dev_err(dev, "sdio_f0_writeb(SDIO_CCCR_IENx) returns %d\n",
++ ret);
++ /* @@@ cleanup */
++ }
++#endif
++
+ #if 0 /* only for hw SDIO */
+ sdio_f0_writeb(func, SDIO_BUS_CD_DISABLE | SDIO_BUS_WIDTH_4BIT,
+ SDIO_CCCR_IF, &ret);
+Index: korig/drivers/spi/spi_bitbang.c
+===================================================================
+--- korig.orig/drivers/spi/spi_bitbang.c 2008-10-01 09:18:09.000000000 -0300
++++ korig/drivers/spi/spi_bitbang.c 2008-10-01 09:34:27.000000000 -0300
+@@ -323,6 +323,9 @@
+ * selected ...)
+ */
+ if (cs_change) {
++ /* @@@ AR6k SPI hack */
++ bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
++ ndelay(nsecs);
+ bitbang->chipselect(spi, BITBANG_CS_ACTIVE);
+ ndelay(nsecs);
+ }
+@@ -380,7 +383,8 @@
+ * cs_change has hinted that the next message will probably
+ * be for this chip too.
+ */
+- if (!(status == 0 && cs_change)) {
++ /* @@@ AR6k SPI hack */
++ if (0&&!(status == 0 && cs_change)) {
+ ndelay(nsecs);
+ bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
+ ndelay(nsecs);
Modified: developers/werner/wlan-spi/patches/series
===================================================================
--- developers/werner/wlan-spi/patches/series 2008-10-01 07:03:22 UTC (rev 4685)
+++ developers/werner/wlan-spi/patches/series 2008-10-01 13:44:28 UTC (rev 4686)
@@ -27,5 +27,9 @@
hack-silence-battery.patch
s3c-spi-fix-int-mode.patch
s3c-spi-from-int-to-poll.patch
-#dont-poll-irq.patch
-#try
+
+# experimental hacks follow
+
+dont-poll-irq.patch
+hif-direct-interrupt.patch
+hif-can-do-async.patch
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