Instead of setting up a kernel pointer to track the current PIO address,
track the offset in the current page, and do an atomic kmap for the page
while doing the actual PIO operations.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 drivers/mmc/host/mvsdio.c | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/drivers/mmc/host/mvsdio.c b/drivers/mmc/host/mvsdio.c
index e22bbff89c8d..d04c78125a4d 100644
--- a/drivers/mmc/host/mvsdio.c
+++ b/drivers/mmc/host/mvsdio.c
@@ -42,7 +42,8 @@ struct mvsd_host {
        unsigned int intr_en;
        unsigned int ctrl;
        unsigned int pio_size;
-       void *pio_ptr;
+       struct scatterlist *pio_sg;
+       unsigned int pio_offset; /* offset in words into the segment */
        unsigned int sg_frags;
        unsigned int ns_per_clk;
        unsigned int clock;
@@ -96,9 +97,9 @@ static int mvsd_setup_data(struct mvsd_host *host, struct 
mmc_data *data)
        if (tmout_index > MVSD_HOST_CTRL_TMOUT_MAX)
                tmout_index = MVSD_HOST_CTRL_TMOUT_MAX;
 
-       dev_dbg(host->dev, "data %s at 0x%08x: blocks=%d blksz=%d tmout=%u 
(%d)\n",
+       dev_dbg(host->dev, "data %s at 0x%08llx: blocks=%d blksz=%d tmout=%u 
(%d)\n",
                (data->flags & MMC_DATA_READ) ? "read" : "write",
-               (u32)sg_virt(data->sg), data->blocks, data->blksz,
+               (u64)sg_phys(data->sg), data->blocks, data->blksz,
                tmout, tmout_index);
 
        host->ctrl &= ~MVSD_HOST_CTRL_TMOUT_MASK;
@@ -118,10 +119,11 @@ static int mvsd_setup_data(struct mvsd_host *host, struct 
mmc_data *data)
                 * boundary.
                 */
                host->pio_size = data->blocks * data->blksz;
-               host->pio_ptr = sg_virt(data->sg);
+               host->pio_sg = data->sg;
+               host->pio_offset = data->sg->offset / 2;
                if (!nodma)
-                       dev_dbg(host->dev, "fallback to PIO for data at 0x%p 
size %d\n",
-                               host->pio_ptr, host->pio_size);
+                       dev_dbg(host->dev, "fallback to PIO for data at 0x%x 
size %d\n",
+                               host->pio_offset, host->pio_size);
                return 1;
        } else {
                dma_addr_t phys_addr;
@@ -291,8 +293,9 @@ static u32 mvsd_finish_data(struct mvsd_host *host, struct 
mmc_data *data,
 {
        void __iomem *iobase = host->base;
 
-       if (host->pio_ptr) {
-               host->pio_ptr = NULL;
+       if (host->pio_sg) {
+               host->pio_sg = NULL;
+               host->pio_offset = 0;
                host->pio_size = 0;
        } else {
                dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->sg_frags,
@@ -376,8 +379,10 @@ static irqreturn_t mvsd_irq(int irq, void *dev)
        if (host->pio_size &&
            (intr_status & host->intr_en &
             (MVSD_NOR_RX_READY | MVSD_NOR_RX_FIFO_8W))) {
-               u16 *p = host->pio_ptr;
+               u16 *base = sg_kmap_atomic(host->pio_sg);
+               u16 *p = base + host->pio_offset;
                int s = host->pio_size;
+
                while (s >= 32 && (intr_status & MVSD_NOR_RX_FIFO_8W)) {
                        readsw(iobase + MVSD_FIFO, p, 16);
                        p += 16;
@@ -416,13 +421,15 @@ static irqreturn_t mvsd_irq(int irq, void *dev)
                }
                dev_dbg(host->dev, "pio %d intr 0x%04x hw_state 0x%04x\n",
                        s, intr_status, mvsd_read(MVSD_HW_STATE));
-               host->pio_ptr = p;
+               host->pio_offset = p - base;
                host->pio_size = s;
+               sg_kunmap_atomic(host->pio_sg, base);
                irq_handled = 1;
        } else if (host->pio_size &&
                   (intr_status & host->intr_en &
                    (MVSD_NOR_TX_AVAIL | MVSD_NOR_TX_FIFO_8W))) {
-               u16 *p = host->pio_ptr;
+               u16 *base = sg_kmap_atomic(host->pio_sg);
+               u16 *p = base + host->pio_offset;
                int s = host->pio_size;
                /*
                 * The TX_FIFO_8W bit is unreliable. When set, bursting
@@ -453,8 +460,9 @@ static irqreturn_t mvsd_irq(int irq, void *dev)
                }
                dev_dbg(host->dev, "pio %d intr 0x%04x hw_state 0x%04x\n",
                        s, intr_status, mvsd_read(MVSD_HW_STATE));
-               host->pio_ptr = p;
+               host->pio_offset = p - base;
                host->pio_size = s;
+               sg_kunmap_atomic(host->pio_sg, base);
                irq_handled = 1;
        }
 
@@ -737,6 +745,7 @@ static int mvsd_probe(struct platform_device *pdev)
        clk_prepare_enable(host->clk);
 
        mmc->ops = &mvsd_ops;
+       mmc->need_kmap = 1;
 
        mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
 
-- 
2.20.1

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