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SubjectRe: [PATCH 07/11] mmc: mvsdio: handle highmem pages
On Mon, 14 Jan 2019 at 10:58, Christoph Hellwig <hch@lst.de> wrote:
>
> 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 <hch@lst.de>
> ---
> drivers/mmc/host/mvsdio.c | 48 +++++++++++++++++++++++----------------
> 1 file changed, 29 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/mmc/host/mvsdio.c b/drivers/mmc/host/mvsdio.c
> index e22bbff89c8d..545e370d6dae 100644
> --- a/drivers/mmc/host/mvsdio.c
> +++ b/drivers/mmc/host/mvsdio.c
> @@ -12,6 +12,7 @@
> #include <linux/module.h>
> #include <linux/init.h>
> #include <linux/io.h>
> +#include <linux/highmem.h>
> #include <linux/platform_device.h>
> #include <linux/mbus.h>
> #include <linux/delay.h>
> @@ -42,7 +43,8 @@ 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 +98,9 @@ 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 +120,11 @@ 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 +294,9 @@ 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,
> @@ -376,11 +380,12 @@ 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 *p = kmap_atomic(sg_page(host->pio_sg));

Seems like a corresponding kunmap_atomic() is missing somewhere.

> + unsigned int o = 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;
> + readsw(iobase + MVSD_FIFO, p + o, 16);
> + o += 16;
> s -= 32;
> intr_status = mvsd_read(MVSD_NOR_INTR_STATUS);
> }
> @@ -391,8 +396,10 @@ static irqreturn_t mvsd_irq(int irq, void *dev)
> */
> if (s <= 32) {
> while (s >= 4 && (intr_status & MVSD_NOR_RX_READY)) {
> - put_unaligned(mvsd_read(MVSD_FIFO), p++);
> - put_unaligned(mvsd_read(MVSD_FIFO), p++);
> + put_unaligned(mvsd_read(MVSD_FIFO), p + o);
> + o++;
> + put_unaligned(mvsd_read(MVSD_FIFO), p + o);
> + o++;
> s -= 4;
> intr_status = mvsd_read(MVSD_NOR_INTR_STATUS);
> }
> @@ -400,7 +407,7 @@ static irqreturn_t mvsd_irq(int irq, void *dev)
> u16 val[2] = {0, 0};
> val[0] = mvsd_read(MVSD_FIFO);
> val[1] = mvsd_read(MVSD_FIFO);
> - memcpy(p, ((void *)&val) + 4 - s, s);
> + memcpy(p + o, ((void *)&val) + 4 - s, s);
> s = 0;
> intr_status = mvsd_read(MVSD_NOR_INTR_STATUS);
> }
> @@ -416,13 +423,14 @@ 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 = o;
> host->pio_size = s;
> 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 *p = kmap_atomic(sg_page(host->pio_sg));

Ditto.

> + unsigned int o = host->pio_offset;
> int s = host->pio_size;
> /*
> * The TX_FIFO_8W bit is unreliable. When set, bursting
> @@ -431,8 +439,10 @@ static irqreturn_t mvsd_irq(int irq, void *dev)
> * TX_FIFO_8W remains set.
> */
> while (s >= 4 && (intr_status & MVSD_NOR_TX_AVAIL)) {
> - mvsd_write(MVSD_FIFO, get_unaligned(p++));
> - mvsd_write(MVSD_FIFO, get_unaligned(p++));
> + mvsd_write(MVSD_FIFO, get_unaligned(p + o));
> + o++;
> + mvsd_write(MVSD_FIFO, get_unaligned(p + o));
> + o++;
> s -= 4;
> intr_status = mvsd_read(MVSD_NOR_INTR_STATUS);
> }
> @@ -453,7 +463,7 @@ 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 = o;
> host->pio_size = s;
> irq_handled = 1;
> }
> --
> 2.20.1
>

Kind regards
Uffe

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