Re: [PATCH V2 3/7] mmc: sdhci: add ADMA2 64-bit addressing support for V4 mode

From: Adrian Hunter
Date: Thu Jun 21 2018 - 09:22:00 EST


On 15/06/18 05:04, Chunyan Zhang wrote:
> ADMA2 64-bit addressing support is divided into V3 mode and V4 mode.
> So there are two kinds of descriptors for ADMA2 64-bit addressing
> i.e. 96-bit Descriptor for V3 mode, and 128-bit Descriptor for V4
> mode. 128-bit Descriptor is aligned to 8-byte.
>
> For V4 mode, ADMA2 64-bit addressing is enabled via Host Control 2
> register.
>
> Signed-off-by: Chunyan Zhang <zhang.chunyan@xxxxxxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 50 +++++++++++++++++++++++++++++++++++-------------
> drivers/mmc/host/sdhci.h | 23 +++++++++++++++++-----
> 2 files changed, 55 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index f57201f..5d3b0d8 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -585,6 +585,8 @@ static void sdhci_adma_table_pre(struct sdhci_host *host,
> void *desc, *align;
> char *buffer;
> int len, offset, i;
> + unsigned int adma2_align = SDHCI_ADMA2_ALIGN(host);
> + unsigned int adma2_mask = SDHCI_ADMA2_MASK(host);
>
> /*
> * The spec does not specify endianness of descriptor table.
> @@ -608,8 +610,8 @@ static void sdhci_adma_table_pre(struct sdhci_host *host,
> * buffer for the (up to three) bytes that screw up the
> * alignment.
> */
> - offset = (SDHCI_ADMA2_ALIGN - (addr & SDHCI_ADMA2_MASK)) &
> - SDHCI_ADMA2_MASK;
> + offset = (adma2_align - (addr & adma2_align)) &
> + adma2_mask;
> if (offset) {
> if (data->flags & MMC_DATA_WRITE) {
> buffer = sdhci_kmap_atomic(sg, &flags);
> @@ -623,8 +625,8 @@ static void sdhci_adma_table_pre(struct sdhci_host *host,
>
> BUG_ON(offset > 65536);
>
> - align += SDHCI_ADMA2_ALIGN;
> - align_addr += SDHCI_ADMA2_ALIGN;
> + align += adma2_align;
> + align_addr += adma2_align;
>
> desc += host->desc_sz;
>
> @@ -668,13 +670,15 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
> void *align;
> char *buffer;
> unsigned long flags;
> + unsigned int adma2_align = SDHCI_ADMA2_ALIGN(host);
> + unsigned int adma2_mask = SDHCI_ADMA2_MASK(host);
>
> if (data->flags & MMC_DATA_READ) {
> bool has_unaligned = false;
>
> /* Do a quick scan of the SG list for any unaligned mappings */
> for_each_sg(data->sg, sg, host->sg_count, i)
> - if (sg_dma_address(sg) & SDHCI_ADMA2_MASK) {
> + if (sg_dma_address(sg) & adma2_mask) {
> has_unaligned = true;
> break;
> }
> @@ -686,15 +690,15 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
> align = host->align_buffer;
>
> for_each_sg(data->sg, sg, host->sg_count, i) {
> - if (sg_dma_address(sg) & SDHCI_ADMA2_MASK) {
> - size = SDHCI_ADMA2_ALIGN -
> - (sg_dma_address(sg) & SDHCI_ADMA2_MASK);
> + if (sg_dma_address(sg) & adma2_mask) {
> + size = adma2_align -
> + (sg_dma_address(sg) & adma2_mask);
>
> buffer = sdhci_kmap_atomic(sg, &flags);
> memcpy(buffer, align, size);
> sdhci_kunmap_atomic(buffer, &flags);
>
> - align += SDHCI_ADMA2_ALIGN;
> + align += adma2_align;
> }
> }
> }
> @@ -3400,6 +3404,26 @@ static int sdhci_allocate_bounce_buffer(struct sdhci_host *host)
> return 0;
> }
>
> +static inline bool sdhci_use_64bit_dma(struct sdhci_host *host)
> +{
> + u32 addr64bit_en;
> +
> + /*
> + * According to SD Host Controller spec v4.10, bit[27] added from
> + * version 4.10 in Capabilities Register is used as 64-bit System
> + * Address support for V4 mode, 64-bit DMA Addressing for V4 mode
> + * is enabled only if 64-bit Addressing =1 in the Host Control 2
> + * register.
> + */
> + if (host->version == SDHCI_SPEC_410 && host->v4_mode) {
> + addr64bit_en = (sdhci_readw(host, SDHCI_HOST_CONTROL2) &
> + SDHCI_CTRL_64BIT_ADDR);

This seems the wrong way around. SDHCI_CTRL_64BIT_ADDR should be set based
on the driver's requirements, not read to determine what the driver will do.

Can you clarify what SDHCI_CTRL_64BIT_ADDR is for?


> + return addr64bit_en && (host->caps & SDHCI_CAN_64BIT_V4);
> + }
> +
> + return host->caps & SDHCI_CAN_64BIT;
> +}
> +
> int sdhci_setup_host(struct sdhci_host *host)
> {
> struct mmc_host *mmc;
> @@ -3471,7 +3495,7 @@ int sdhci_setup_host(struct sdhci_host *host)
> * SDHCI_QUIRK2_BROKEN_64_BIT_DMA must be left to the drivers to
> * implement.
> */
> - if (host->caps & SDHCI_CAN_64BIT)
> + if (sdhci_use_64bit_dma(host))
> host->flags |= SDHCI_USE_64_BIT_DMA;
>
> if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA)) {
> @@ -3505,15 +3529,15 @@ int sdhci_setup_host(struct sdhci_host *host)
> */
> if (host->flags & SDHCI_USE_64_BIT_DMA) {
> host->adma_table_sz = (SDHCI_MAX_SEGS * 2 + 1) *
> - SDHCI_ADMA2_64_DESC_SZ;
> - host->desc_sz = SDHCI_ADMA2_64_DESC_SZ;
> + SDHCI_ADMA2_64_DESC_SZ(host);
> + host->desc_sz = SDHCI_ADMA2_64_DESC_SZ(host);
> } else {
> host->adma_table_sz = (SDHCI_MAX_SEGS * 2 + 1) *
> SDHCI_ADMA2_32_DESC_SZ;
> host->desc_sz = SDHCI_ADMA2_32_DESC_SZ;
> }
>
> - host->align_buffer_sz = SDHCI_MAX_SEGS * SDHCI_ADMA2_ALIGN;
> + host->align_buffer_sz = SDHCI_MAX_SEGS * SDHCI_ADMA2_ALIGN(host);
> buf = dma_alloc_coherent(mmc_dev(mmc), host->align_buffer_sz +
> host->adma_table_sz, &dma, GFP_KERNEL);

This needs to be dma_zalloc_coherent to ensure that the unused 4-bytes in
each 16-byte descriptor is zero.

> if (!buf) {
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 128b0ba..820a863 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -185,6 +185,7 @@
> #define SDHCI_CTRL_EXEC_TUNING 0x0040
> #define SDHCI_CTRL_TUNED_CLK 0x0080
> #define SDHCI_CTRL_V4_MODE 0x1000
> +#define SDHCI_CTRL_64BIT_ADDR 0x2000
> #define SDHCI_CTRL_PRESET_VAL_ENABLE 0x8000
>
> #define SDHCI_CAPABILITIES 0x40
> @@ -206,6 +207,7 @@
> #define SDHCI_CAN_VDD_300 0x02000000
> #define SDHCI_CAN_VDD_180 0x04000000
> #define SDHCI_CAN_64BIT 0x10000000
> +#define SDHCI_CAN_64BIT_V4 0x8000000

Please make it 8 digits and put it in the right numerical order

>
> #define SDHCI_SUPPORT_SDR50 0x00000001
> #define SDHCI_SUPPORT_SDR104 0x00000002
> @@ -297,9 +299,14 @@ struct sdhci_adma2_32_desc {
> __le32 addr;
> } __packed __aligned(4);
>
> -/* ADMA2 data alignment */
> -#define SDHCI_ADMA2_ALIGN 4
> -#define SDHCI_ADMA2_MASK (SDHCI_ADMA2_ALIGN - 1)
> +/*
> + * ADMA2 data alignment
> + * According to SD Host Controller spec v4.10, if Host Version 4 Enable is set
> + * in the Host Control 2 register, 128-bit Descriptor will be selected which
> + * shall be aligned 8-byte address boundary.
> + */
> +#define SDHCI_ADMA2_ALIGN(host) ((host)->v4_mode ? 8 : 4)
> +#define SDHCI_ADMA2_MASK(host) (SDHCI_ADMA2_ALIGN(host) - 1)

Are you really sure about that, because it reads like it is still 4-byte
alignment for data and 8-byte alignment for descriptors, which is what we
already do.

>
> /*
> * ADMA2 descriptor alignment. Some controllers (e.g. Intel) require 8 byte
> @@ -308,8 +315,14 @@ struct sdhci_adma2_32_desc {
> */
> #define SDHCI_ADMA2_DESC_ALIGN 8
>
> -/* ADMA2 64-bit DMA descriptor size */
> -#define SDHCI_ADMA2_64_DESC_SZ 12
> +/*
> + * ADMA2 64-bit DMA descriptor size
> + * According to SD Host Controller spec v4.10, there are two kinds of
> + * descriptors for 64-bit addressing mode: 96-bit Descriptor and 128-bit
> + * Descriptor, if Host Version 4 Enable is set in the Host Control 2
> + * register, 128-bit Descriptor will be selected.
> + */
> +#define SDHCI_ADMA2_64_DESC_SZ(host) ((host)->v4_mode ? 16 : 12)
>
> /*
> * ADMA2 64-bit descriptor. Note 12-byte descriptor can't always be 8-byte
>