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linux/drivers/mmc/pxamci.c
David Howells 7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:10:12 +01:00

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/*
* linux/drivers/mmc/pxa.c - PXA MMCI driver
*
* Copyright (C) 2003 Russell King, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This hardware is really sick:
* - No way to clear interrupts.
* - Have to turn off the clock whenever we touch the device.
* - Doesn't tell you how many data blocks were transferred.
* Yuck!
*
* 1 and 3 byte data transfers not supported
* max block length up to 1023
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/mmc/host.h>
#include <linux/mmc/protocol.h>
#include <asm/dma.h>
#include <asm/io.h>
#include <asm/scatterlist.h>
#include <asm/sizes.h>
#include <asm/arch/pxa-regs.h>
#include <asm/arch/mmc.h>
#include "pxamci.h"
#define DRIVER_NAME "pxa2xx-mci"
#define NR_SG 1
struct pxamci_host {
struct mmc_host *mmc;
spinlock_t lock;
struct resource *res;
void __iomem *base;
int irq;
int dma;
unsigned int clkrt;
unsigned int cmdat;
unsigned int imask;
unsigned int power_mode;
struct pxamci_platform_data *pdata;
struct mmc_request *mrq;
struct mmc_command *cmd;
struct mmc_data *data;
dma_addr_t sg_dma;
struct pxa_dma_desc *sg_cpu;
unsigned int dma_len;
unsigned int dma_dir;
};
static void pxamci_stop_clock(struct pxamci_host *host)
{
if (readl(host->base + MMC_STAT) & STAT_CLK_EN) {
unsigned long timeout = 10000;
unsigned int v;
writel(STOP_CLOCK, host->base + MMC_STRPCL);
do {
v = readl(host->base + MMC_STAT);
if (!(v & STAT_CLK_EN))
break;
udelay(1);
} while (timeout--);
if (v & STAT_CLK_EN)
dev_err(mmc_dev(host->mmc), "unable to stop clock\n");
}
}
static void pxamci_enable_irq(struct pxamci_host *host, unsigned int mask)
{
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
host->imask &= ~mask;
writel(host->imask, host->base + MMC_I_MASK);
spin_unlock_irqrestore(&host->lock, flags);
}
static void pxamci_disable_irq(struct pxamci_host *host, unsigned int mask)
{
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
host->imask |= mask;
writel(host->imask, host->base + MMC_I_MASK);
spin_unlock_irqrestore(&host->lock, flags);
}
static void pxamci_setup_data(struct pxamci_host *host, struct mmc_data *data)
{
unsigned int nob = data->blocks;
unsigned long long clks;
unsigned int timeout;
u32 dcmd;
int i;
host->data = data;
if (data->flags & MMC_DATA_STREAM)
nob = 0xffff;
writel(nob, host->base + MMC_NOB);
writel(data->blksz, host->base + MMC_BLKLEN);
clks = (unsigned long long)data->timeout_ns * CLOCKRATE;
do_div(clks, 1000000000UL);
timeout = (unsigned int)clks + (data->timeout_clks << host->clkrt);
writel((timeout + 255) / 256, host->base + MMC_RDTO);
if (data->flags & MMC_DATA_READ) {
host->dma_dir = DMA_FROM_DEVICE;
dcmd = DCMD_INCTRGADDR | DCMD_FLOWTRG;
DRCMRTXMMC = 0;
DRCMRRXMMC = host->dma | DRCMR_MAPVLD;
} else {
host->dma_dir = DMA_TO_DEVICE;
dcmd = DCMD_INCSRCADDR | DCMD_FLOWSRC;
DRCMRRXMMC = 0;
DRCMRTXMMC = host->dma | DRCMR_MAPVLD;
}
dcmd |= DCMD_BURST32 | DCMD_WIDTH1;
host->dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
host->dma_dir);
for (i = 0; i < host->dma_len; i++) {
if (data->flags & MMC_DATA_READ) {
host->sg_cpu[i].dsadr = host->res->start + MMC_RXFIFO;
host->sg_cpu[i].dtadr = sg_dma_address(&data->sg[i]);
} else {
host->sg_cpu[i].dsadr = sg_dma_address(&data->sg[i]);
host->sg_cpu[i].dtadr = host->res->start + MMC_TXFIFO;
}
host->sg_cpu[i].dcmd = dcmd | sg_dma_len(&data->sg[i]);
host->sg_cpu[i].ddadr = host->sg_dma + (i + 1) *
sizeof(struct pxa_dma_desc);
}
host->sg_cpu[host->dma_len - 1].ddadr = DDADR_STOP;
wmb();
DDADR(host->dma) = host->sg_dma;
DCSR(host->dma) = DCSR_RUN;
}
static void pxamci_start_cmd(struct pxamci_host *host, struct mmc_command *cmd, unsigned int cmdat)
{
WARN_ON(host->cmd != NULL);
host->cmd = cmd;
if (cmd->flags & MMC_RSP_BUSY)
cmdat |= CMDAT_BUSY;
#define RSP_TYPE(x) ((x) & ~(MMC_RSP_BUSY|MMC_RSP_OPCODE))
switch (RSP_TYPE(mmc_resp_type(cmd))) {
case RSP_TYPE(MMC_RSP_R1): /* r1, r1b, r6 */
cmdat |= CMDAT_RESP_SHORT;
break;
case RSP_TYPE(MMC_RSP_R3):
cmdat |= CMDAT_RESP_R3;
break;
case RSP_TYPE(MMC_RSP_R2):
cmdat |= CMDAT_RESP_R2;
break;
default:
break;
}
writel(cmd->opcode, host->base + MMC_CMD);
writel(cmd->arg >> 16, host->base + MMC_ARGH);
writel(cmd->arg & 0xffff, host->base + MMC_ARGL);
writel(cmdat, host->base + MMC_CMDAT);
writel(host->clkrt, host->base + MMC_CLKRT);
writel(START_CLOCK, host->base + MMC_STRPCL);
pxamci_enable_irq(host, END_CMD_RES);
}
static void pxamci_finish_request(struct pxamci_host *host, struct mmc_request *mrq)
{
host->mrq = NULL;
host->cmd = NULL;
host->data = NULL;
mmc_request_done(host->mmc, mrq);
}
static int pxamci_cmd_done(struct pxamci_host *host, unsigned int stat)
{
struct mmc_command *cmd = host->cmd;
int i;
u32 v;
if (!cmd)
return 0;
host->cmd = NULL;
/*
* Did I mention this is Sick. We always need to
* discard the upper 8 bits of the first 16-bit word.
*/
v = readl(host->base + MMC_RES) & 0xffff;
for (i = 0; i < 4; i++) {
u32 w1 = readl(host->base + MMC_RES) & 0xffff;
u32 w2 = readl(host->base + MMC_RES) & 0xffff;
cmd->resp[i] = v << 24 | w1 << 8 | w2 >> 8;
v = w2;
}
if (stat & STAT_TIME_OUT_RESPONSE) {
cmd->error = MMC_ERR_TIMEOUT;
} else if (stat & STAT_RES_CRC_ERR && cmd->flags & MMC_RSP_CRC) {
#ifdef CONFIG_PXA27x
/*
* workaround for erratum #42:
* Intel PXA27x Family Processor Specification Update Rev 001
*/
if (cmd->opcode == MMC_ALL_SEND_CID ||
cmd->opcode == MMC_SEND_CSD ||
cmd->opcode == MMC_SEND_CID) {
/* a bogus CRC error can appear if the msb of
the 15 byte response is a one */
if ((cmd->resp[0] & 0x80000000) == 0)
cmd->error = MMC_ERR_BADCRC;
} else {
pr_debug("ignoring CRC from command %d - *risky*\n",cmd->opcode);
}
#else
cmd->error = MMC_ERR_BADCRC;
#endif
}
pxamci_disable_irq(host, END_CMD_RES);
if (host->data && cmd->error == MMC_ERR_NONE) {
pxamci_enable_irq(host, DATA_TRAN_DONE);
} else {
pxamci_finish_request(host, host->mrq);
}
return 1;
}
static int pxamci_data_done(struct pxamci_host *host, unsigned int stat)
{
struct mmc_data *data = host->data;
if (!data)
return 0;
DCSR(host->dma) = 0;
dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->dma_len,
host->dma_dir);
if (stat & STAT_READ_TIME_OUT)
data->error = MMC_ERR_TIMEOUT;
else if (stat & (STAT_CRC_READ_ERROR|STAT_CRC_WRITE_ERROR))
data->error = MMC_ERR_BADCRC;
/*
* There appears to be a hardware design bug here. There seems to
* be no way to find out how much data was transferred to the card.
* This means that if there was an error on any block, we mark all
* data blocks as being in error.
*/
if (data->error == MMC_ERR_NONE)
data->bytes_xfered = data->blocks * data->blksz;
else
data->bytes_xfered = 0;
pxamci_disable_irq(host, DATA_TRAN_DONE);
host->data = NULL;
if (host->mrq->stop) {
pxamci_stop_clock(host);
pxamci_start_cmd(host, host->mrq->stop, 0);
} else {
pxamci_finish_request(host, host->mrq);
}
return 1;
}
static irqreturn_t pxamci_irq(int irq, void *devid)
{
struct pxamci_host *host = devid;
unsigned int ireg;
int handled = 0;
ireg = readl(host->base + MMC_I_REG);
if (ireg) {
unsigned stat = readl(host->base + MMC_STAT);
pr_debug("PXAMCI: irq %08x stat %08x\n", ireg, stat);
if (ireg & END_CMD_RES)
handled |= pxamci_cmd_done(host, stat);
if (ireg & DATA_TRAN_DONE)
handled |= pxamci_data_done(host, stat);
}
return IRQ_RETVAL(handled);
}
static void pxamci_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
struct pxamci_host *host = mmc_priv(mmc);
unsigned int cmdat;
WARN_ON(host->mrq != NULL);
host->mrq = mrq;
pxamci_stop_clock(host);
cmdat = host->cmdat;
host->cmdat &= ~CMDAT_INIT;
if (mrq->data) {
pxamci_setup_data(host, mrq->data);
cmdat &= ~CMDAT_BUSY;
cmdat |= CMDAT_DATAEN | CMDAT_DMAEN;
if (mrq->data->flags & MMC_DATA_WRITE)
cmdat |= CMDAT_WRITE;
if (mrq->data->flags & MMC_DATA_STREAM)
cmdat |= CMDAT_STREAM;
}
pxamci_start_cmd(host, mrq->cmd, cmdat);
}
static int pxamci_get_ro(struct mmc_host *mmc)
{
struct pxamci_host *host = mmc_priv(mmc);
if (host->pdata && host->pdata->get_ro)
return host->pdata->get_ro(mmc->dev);
/* Host doesn't support read only detection so assume writeable */
return 0;
}
static void pxamci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
struct pxamci_host *host = mmc_priv(mmc);
if (ios->clock) {
unsigned int clk = CLOCKRATE / ios->clock;
if (CLOCKRATE / clk > ios->clock)
clk <<= 1;
host->clkrt = fls(clk) - 1;
pxa_set_cken(CKEN12_MMC, 1);
/*
* we write clkrt on the next command
*/
} else {
pxamci_stop_clock(host);
pxa_set_cken(CKEN12_MMC, 0);
}
if (host->power_mode != ios->power_mode) {
host->power_mode = ios->power_mode;
if (host->pdata && host->pdata->setpower)
host->pdata->setpower(mmc->dev, ios->vdd);
if (ios->power_mode == MMC_POWER_ON)
host->cmdat |= CMDAT_INIT;
}
pr_debug("PXAMCI: clkrt = %x cmdat = %x\n",
host->clkrt, host->cmdat);
}
static struct mmc_host_ops pxamci_ops = {
.request = pxamci_request,
.get_ro = pxamci_get_ro,
.set_ios = pxamci_set_ios,
};
static void pxamci_dma_irq(int dma, void *devid)
{
printk(KERN_ERR "DMA%d: IRQ???\n", dma);
DCSR(dma) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
}
static irqreturn_t pxamci_detect_irq(int irq, void *devid)
{
struct pxamci_host *host = mmc_priv(devid);
mmc_detect_change(devid, host->pdata->detect_delay);
return IRQ_HANDLED;
}
static int pxamci_probe(struct platform_device *pdev)
{
struct mmc_host *mmc;
struct pxamci_host *host = NULL;
struct resource *r;
int ret, irq;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
irq = platform_get_irq(pdev, 0);
if (!r || irq < 0)
return -ENXIO;
r = request_mem_region(r->start, SZ_4K, DRIVER_NAME);
if (!r)
return -EBUSY;
mmc = mmc_alloc_host(sizeof(struct pxamci_host), &pdev->dev);
if (!mmc) {
ret = -ENOMEM;
goto out;
}
mmc->ops = &pxamci_ops;
mmc->f_min = CLOCKRATE_MIN;
mmc->f_max = CLOCKRATE_MAX;
/*
* We can do SG-DMA, but we don't because we never know how much
* data we successfully wrote to the card.
*/
mmc->max_phys_segs = NR_SG;
/*
* Our hardware DMA can handle a maximum of one page per SG entry.
*/
mmc->max_seg_size = PAGE_SIZE;
host = mmc_priv(mmc);
host->mmc = mmc;
host->dma = -1;
host->pdata = pdev->dev.platform_data;
mmc->ocr_avail = host->pdata ?
host->pdata->ocr_mask :
MMC_VDD_32_33|MMC_VDD_33_34;
host->sg_cpu = dma_alloc_coherent(&pdev->dev, PAGE_SIZE, &host->sg_dma, GFP_KERNEL);
if (!host->sg_cpu) {
ret = -ENOMEM;
goto out;
}
spin_lock_init(&host->lock);
host->res = r;
host->irq = irq;
host->imask = MMC_I_MASK_ALL;
host->base = ioremap(r->start, SZ_4K);
if (!host->base) {
ret = -ENOMEM;
goto out;
}
/*
* Ensure that the host controller is shut down, and setup
* with our defaults.
*/
pxamci_stop_clock(host);
writel(0, host->base + MMC_SPI);
writel(64, host->base + MMC_RESTO);
writel(host->imask, host->base + MMC_I_MASK);
host->dma = pxa_request_dma(DRIVER_NAME, DMA_PRIO_LOW,
pxamci_dma_irq, host);
if (host->dma < 0) {
ret = -EBUSY;
goto out;
}
ret = request_irq(host->irq, pxamci_irq, 0, DRIVER_NAME, host);
if (ret)
goto out;
platform_set_drvdata(pdev, mmc);
if (host->pdata && host->pdata->init)
host->pdata->init(&pdev->dev, pxamci_detect_irq, mmc);
mmc_add_host(mmc);
return 0;
out:
if (host) {
if (host->dma >= 0)
pxa_free_dma(host->dma);
if (host->base)
iounmap(host->base);
if (host->sg_cpu)
dma_free_coherent(&pdev->dev, PAGE_SIZE, host->sg_cpu, host->sg_dma);
}
if (mmc)
mmc_free_host(mmc);
release_resource(r);
return ret;
}
static int pxamci_remove(struct platform_device *pdev)
{
struct mmc_host *mmc = platform_get_drvdata(pdev);
platform_set_drvdata(pdev, NULL);
if (mmc) {
struct pxamci_host *host = mmc_priv(mmc);
if (host->pdata && host->pdata->exit)
host->pdata->exit(&pdev->dev, mmc);
mmc_remove_host(mmc);
pxamci_stop_clock(host);
writel(TXFIFO_WR_REQ|RXFIFO_RD_REQ|CLK_IS_OFF|STOP_CMD|
END_CMD_RES|PRG_DONE|DATA_TRAN_DONE,
host->base + MMC_I_MASK);
DRCMRRXMMC = 0;
DRCMRTXMMC = 0;
free_irq(host->irq, host);
pxa_free_dma(host->dma);
iounmap(host->base);
dma_free_coherent(&pdev->dev, PAGE_SIZE, host->sg_cpu, host->sg_dma);
release_resource(host->res);
mmc_free_host(mmc);
}
return 0;
}
#ifdef CONFIG_PM
static int pxamci_suspend(struct platform_device *dev, pm_message_t state)
{
struct mmc_host *mmc = platform_get_drvdata(dev);
int ret = 0;
if (mmc)
ret = mmc_suspend_host(mmc, state);
return ret;
}
static int pxamci_resume(struct platform_device *dev)
{
struct mmc_host *mmc = platform_get_drvdata(dev);
int ret = 0;
if (mmc)
ret = mmc_resume_host(mmc);
return ret;
}
#else
#define pxamci_suspend NULL
#define pxamci_resume NULL
#endif
static struct platform_driver pxamci_driver = {
.probe = pxamci_probe,
.remove = pxamci_remove,
.suspend = pxamci_suspend,
.resume = pxamci_resume,
.driver = {
.name = DRIVER_NAME,
},
};
static int __init pxamci_init(void)
{
return platform_driver_register(&pxamci_driver);
}
static void __exit pxamci_exit(void)
{
platform_driver_unregister(&pxamci_driver);
}
module_init(pxamci_init);
module_exit(pxamci_exit);
MODULE_DESCRIPTION("PXA Multimedia Card Interface Driver");
MODULE_LICENSE("GPL");
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