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Date: Sat, 23 Oct 2010 01:53:48 +0200
From: Maxim Levitsky <maximlevitsky@...il.com>
To: Alex Dubov <oakad@...oo.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
LKML <linux-kernel@...r.kernel.org>,
Maxim Levitsky <maximlevitsky@...il.com>
Subject: [PATCH 20/29] memstick: jmb38x_ms: rework PIO
Rewrite PIO code to be just simplier and shorter,
and comment not so obivous parts.
Signed-off-by: Maxim Levitsky<maximlevitsky@...il.com>
---
drivers/memstick/host/jmb38x_ms.c | 283 +++++++++++++------------------------
drivers/memstick/host/jmb38x_ms.h | 17 +--
2 files changed, 103 insertions(+), 197 deletions(-)
diff --git a/drivers/memstick/host/jmb38x_ms.c b/drivers/memstick/host/jmb38x_ms.c
index bcdb785..5af0a52 100644
--- a/drivers/memstick/host/jmb38x_ms.c
+++ b/drivers/memstick/host/jmb38x_ms.c
@@ -17,6 +17,7 @@
#include <linux/highmem.h>
#include <linux/memstick.h>
#include <linux/slab.h>
+#include <linux/scatterlist.h>
#include "jmb38x_ms.h"
static int no_dma;
@@ -103,39 +104,34 @@ static inline int j38ms_write_fifo_dword_pio(struct j38ms_host *host, u32 dword)
static unsigned int j38ms_read_fifo_pio(struct j38ms_host *host,
unsigned char *buf, unsigned int length)
{
- unsigned int off = 0;
+ unsigned int orig_len = length;
+ unsigned char tmp_buf[4];
- while (host->io_pos && length) {
- buf[off++] = host->io_word[0] & 0xff;
- host->io_word[0] >>= 8;
- length--;
- host->io_pos--;
+ /* Read bytes from last saved part */
+ if (host->pio_tmp_buf_len) {
+ int count = min(host->pio_tmp_buf_len, length);
+ memcpy(buf, host->pio_tmp_buf, count);
+ buf += count;
+ length -= count;
}
- if (!length)
- return off;
+ /* Read aligned data*/
+ for (; length >= 4 ; buf += 4, length -= 4)
+ if (j38ms_read_fifo_dword_pio(host, (u32 *)buf))
+ return orig_len - length;
- while (!(STATUS_FIFO_EMPTY & readl(host->addr + STATUS))) {
- if (length < 4)
- break;
- *(unsigned int *)(buf + off) = __raw_readl(host->addr + DATA);
- length -= 4;
- off += 4;
- }
+ /* Read last 4 bytes, and
+ save unconsumed part of it to the pio_tmp_buf */
+ if (length && !j38ms_read_fifo_dword_pio(host, (u32 *)tmp_buf)) {
- if (length
- && !(STATUS_FIFO_EMPTY & readl(host->addr + STATUS))) {
- host->io_word[0] = readl(host->addr + DATA);
- for (host->io_pos = 4; host->io_pos; --host->io_pos) {
- buf[off++] = host->io_word[0] & 0xff;
- host->io_word[0] >>= 8;
- length--;
- if (!length)
- break;
- }
+ host->pio_tmp_buf_len = 4 - length;
+ memcpy(buf, tmp_buf, length);
+ memcpy(host->pio_tmp_buf,
+ tmp_buf + length, host->pio_tmp_buf_len);
+ length = 0;
}
- return off;
+ return orig_len - length;
}
/* Write TPC data through normal PIO fifo */
@@ -143,175 +139,106 @@ static unsigned int j38ms_write_fifo_pio(struct j38ms_host *host,
unsigned char *buf,
unsigned int length)
{
- unsigned int off = 0;
-
- if (host->io_pos) {
- while (host->io_pos < 4 && length) {
- host->io_word[0] |= buf[off++] << (host->io_pos * 8);
- host->io_pos++;
- length--;
+ unsigned int orig_len = length;
+
+ /* Complete the last saved bytes*/
+ if (host->pio_tmp_buf_len) {
+ int count = min(4 - host->pio_tmp_buf_len, length);
+ memcpy(host->pio_tmp_buf + host->pio_tmp_buf_len, buf, count);
+ buf += count;
+ length -= count;
+
+ if (host->pio_tmp_buf_len == 4) {
+ if (j38ms_write_fifo_dword_pio(
+ host, *(u32 *)host->pio_tmp_buf))
+ return orig_len - length;
+ else
+ host->pio_tmp_buf_len = 0;
}
}
- if (host->io_pos == 4
- && !(STATUS_FIFO_FULL & readl(host->addr + STATUS))) {
- writel(host->io_word[0], host->addr + DATA);
- host->io_pos = 0;
- host->io_word[0] = 0;
- } else if (host->io_pos) {
- return off;
- }
-
- if (!length)
- return off;
-
- while (!(STATUS_FIFO_FULL & readl(host->addr + STATUS))) {
- if (length < 4)
- break;
-
- __raw_writel(*(unsigned int *)(buf + off),
- host->addr + DATA);
- length -= 4;
- off += 4;
- }
+ /* Write aligned data to hardware */
+ for (; length >= 4 ; length -= 4, buf += 4)
+ if (j38ms_write_fifo_dword_pio(host, *(u32 *)buf))
+ return orig_len - length;
- switch (length) {
- case 3:
- host->io_word[0] |= buf[off + 2] << 16;
- host->io_pos++;
- case 2:
- host->io_word[0] |= buf[off + 1] << 8;
- host->io_pos++;
- case 1:
- host->io_word[0] |= buf[off];
- host->io_pos++;
+ /* Save last 3-1 bytes to buffer, because we can't send them now*/
+ if (length) {
+ memset(host->pio_tmp_buf, 0, 4);
+ memcpy(host->pio_tmp_buf, buf, length);
+ host->pio_tmp_buf_len = length;
}
- off += host->io_pos;
-
- return off;
+ return orig_len - length;
}
+
/* Transfer data between current request and FIFO */
-static int j38ms_transfer_data(struct j38ms_host *host)
+static void j38ms_transfer_pio(struct j38ms_host *host)
{
- unsigned int length;
- unsigned int off;
- unsigned int t_size, p_cnt;
unsigned char *buf;
- struct page *pg;
+ unsigned int len;
unsigned long flags = 0;
- if (host->req->long_data) {
- length = host->req->sg.length - host->block_pos;
- off = host->req->sg.offset + host->block_pos;
- } else {
- length = host->req->data_len - host->block_pos;
- off = 0;
- }
+ if (host->req->long_data)
+ local_irq_save(flags);
- while (length) {
- unsigned int uninitialized_var(p_off);
+ dbg_v(host, "PIO: new transfer");
+ while (1) {
if (host->req->long_data) {
- pg = nth_page(sg_page(&host->req->sg),
- off >> PAGE_SHIFT);
- p_off = offset_in_page(off);
- p_cnt = PAGE_SIZE - p_off;
- p_cnt = min(p_cnt, length);
-
- local_irq_save(flags);
- buf = kmap_atomic(pg, KM_BIO_SRC_IRQ) + p_off;
+ if (!sg_miter_next(&host->pio_sg_iter))
+ break;
+
+ buf = host->pio_sg_iter.addr;
+ len = host->pio_sg_iter.length;
} else {
- buf = host->req->data + host->block_pos;
- p_cnt = host->req->data_len - host->block_pos;
+ buf = host->req->data + host->pio_offset;
+ len = host->req->data_len - host->pio_offset;
+
+ if (!len)
+ break;
}
- if (host->req->data_dir == WRITE)
- t_size = !(host->cmd_flags & REG_DATA)
- ? j38ms_write_fifo_pio(host, buf, p_cnt)
- : j38ms_write_tpc_inline(host, buf, p_cnt);
- else
- t_size = !(host->cmd_flags & REG_DATA)
- ? j38ms_read_fifo_pio(host, buf, p_cnt)
- : j38ms_read_tpc_inline(host, buf, p_cnt);
+ len = host->req->data_dir == WRITE ?
+ j38ms_write_fifo_pio(host, buf, len) :
+ j38ms_read_fifo_pio(host, buf, len);
- if (host->req->long_data) {
- kunmap_atomic(buf - p_off, KM_BIO_SRC_IRQ);
- local_irq_restore(flags);
- }
+ if (host->req->long_data)
+ host->pio_sg_iter.consumed = len;
+ else
+ host->pio_offset += len;
- if (!t_size)
- break;
- host->block_pos += t_size;
- length -= t_size;
- off += t_size;
+ dbg(host, "PIO: transfered %d bytes", len);
+ if (!len)
+ goto exit;
}
- if (!length && host->req->data_dir == WRITE) {
- if (host->cmd_flags & REG_DATA) {
- writel(host->io_word[0], host->addr + TPC_P0);
- writel(host->io_word[1], host->addr + TPC_P1);
- } else if (host->io_pos) {
- writel(host->io_word[0], host->addr + DATA);
- }
+ /* Write last non-complete dword of the data */
+ if (host->req->data_dir == WRITE && host->pio_tmp_buf_len) {
+ if (!j38ms_write_fifo_dword_pio(host,
+ *(u32 *)host->pio_tmp_buf))
+ host->pio_tmp_buf_len = 0;
+ }
+exit:
+ if (host->req->long_data) {
+ sg_miter_stop(&host->pio_sg_iter);
+ local_irq_restore(flags);
}
-
- return length;
}
/* Read short TPC data (up to 8 bytes) via 2 special registers*/
-static unsigned int j38ms_read_tpc_inline(struct j38ms_host *host,
- unsigned char *buf,
- unsigned int length)
+static void j38ms_read_tpc_inline(struct j38ms_host *host)
{
- unsigned int off = 0;
-
- while (host->io_pos > 4 && length) {
- buf[off++] = host->io_word[0] & 0xff;
- host->io_word[0] >>= 8;
- length--;
- host->io_pos--;
- }
-
- if (!length)
- return off;
-
- while (host->io_pos && length) {
- buf[off++] = host->io_word[1] & 0xff;
- host->io_word[1] >>= 8;
- length--;
- host->io_pos--;
- }
-
- return off;
+ *(u32 *)(host->req->data + 0) = j38ms_read_reg_raw(host, TPC_P0);
+ *(u32 *)(host->req->data + 4) = j38ms_read_reg_raw(host, TPC_P1);
}
/* Write short TPC data (up to 8 bytes) through 2 special registers */
-static unsigned int j38ms_write_tpc_inline(struct j38ms_host *host,
- unsigned char *buf,
- unsigned int length)
+static void j38ms_write_tpc_inline(struct j38ms_host *host)
{
- unsigned int off = 0;
-
- while (host->io_pos < 4 && length) {
- host->io_word[0] &= ~(0xff << (host->io_pos * 8));
- host->io_word[0] |= buf[off++] << (host->io_pos * 8);
- host->io_pos++;
- length--;
- }
-
- if (!length)
- return off;
-
- while (host->io_pos < 8 && length) {
- host->io_word[1] &= ~(0xff << (host->io_pos * 8));
- host->io_word[1] |= buf[off++] << (host->io_pos * 8);
- host->io_pos++;
- length--;
- }
-
- return off;
+ j38ms_write_reg_raw(host, TPC_P0, *(u32 *)(host->req->data + 0));
+ j38ms_write_reg_raw(host, TPC_P1, *(u32 *)(host->req->data + 4));
}
/*
@@ -344,10 +271,6 @@ static int j38ms_execute_tpc(struct memstick_host *msh)
dev_dbg(&msh->dev, "hstatus %08x\n", readl(host->addr + STATUS));
host->cmd_flags = 0;
- host->block_pos = 0;
- host->io_pos = 0;
- host->io_word[0] = 0;
- host->io_word[1] = 0;
cmd = host->req->tpc << 16;
cmd |= TPC_DATA_SEL;
@@ -407,11 +330,8 @@ static int j38ms_execute_tpc(struct memstick_host *msh)
host->cmd_flags |= REG_DATA;
cmd |= data_len & 0xf;
- if (host->req->data_dir == WRITE) {
- j38ms_transfer_data(host);
- writel(host->io_word[0], host->addr + TPC_P0);
- writel(host->io_word[1], host->addr + TPC_P1);
- }
+ if (host->req->data_dir == WRITE)
+ j38ms_write_tpc_inline(host);
}
mod_timer(&host->timer, jiffies + host->timeout_jiffies);
@@ -504,10 +424,10 @@ static irqreturn_t j38ms_isr(int irq, void *dev_id)
} else {
if (irq_status & (INT_STATUS_FIFO_RRDY
| INT_STATUS_FIFO_WRDY))
- j38ms_transfer_data(host);
+ j38ms_transfer_pio(host);
if (irq_status & INT_STATUS_EOTRAN) {
- j38ms_transfer_data(host);
+ j38ms_transfer_pio(host);
host->cmd_flags |= FIFO_READY;
}
}
@@ -515,17 +435,8 @@ static irqreturn_t j38ms_isr(int irq, void *dev_id)
if (irq_status & INT_STATUS_EOTPC) {
host->cmd_flags |= CMD_READY;
if (host->cmd_flags & REG_DATA) {
- if (host->req->data_dir == READ) {
- host->io_word[0]
- = readl(host->addr
- + TPC_P0);
- host->io_word[1]
- = readl(host->addr
- + TPC_P1);
- host->io_pos = 8;
-
- j38ms_transfer_data(host);
- }
+ if (host->req->data_dir == READ)
+ j38ms_read_tpc_inline(host);
host->cmd_flags |= FIFO_READY;
}
}
diff --git a/drivers/memstick/host/jmb38x_ms.h b/drivers/memstick/host/jmb38x_ms.h
index 35b8bca..d7dffb6 100644
--- a/drivers/memstick/host/jmb38x_ms.h
+++ b/drivers/memstick/host/jmb38x_ms.h
@@ -151,13 +151,16 @@ struct j38ms_host {
int id;
char host_id[32];
int irq;
- unsigned int block_pos;
unsigned long timeout_jiffies;
struct timer_list timer;
struct memstick_request *req;
unsigned char cmd_flags;
- unsigned char io_pos;
- unsigned int io_word[2];
+
+ /* PIO state */
+ struct sg_mapping_iter pio_sg_iter;
+ unsigned char pio_offset;
+ unsigned char pio_tmp_buf[4];
+ unsigned int pio_tmp_buf_len;
};
struct j38ms {
@@ -187,11 +190,3 @@ enum {
#define dbg(host, format, ...) __dbg(host, 1, format, ## __VA_ARGS__)
#define dbg_v(host, format, ...) __dbg(host, 2, format, ## __VA_ARGS__)
#define dbg_reg(host, format, ...) __dbg(host, 3, format, ## __VA_ARGS__)
-
-static unsigned int j38ms_read_tpc_inline(struct j38ms_host *host,
- unsigned char *buf,
- unsigned int length);
-
-static unsigned int j38ms_write_tpc_inline(struct j38ms_host *host,
- unsigned char *buf,
- unsigned int length);
--
1.7.1
--
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