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Date: Tue, 15 Sep 2015 16:52:07 +0800
From: Shawn Lin <shawn.lin@...k-chips.com>
To: Jaehoon Chung <jh80.chung@...sung.com>, ulf.hansson@...aro.org
Cc: shawn.lin@...k-chips.com, Vineet.Gupta1@...opsys.com,
Wei Xu <xuwei5@...ilicon.com>,
Joachim Eastwood <manabian@...il.com>,
Alexey Brodkin <abrodkin@...opsys.com>,
Kukjin Kim <kgene@...nel.org>,
Krzysztof Kozlowski <k.kozlowski@...sung.com>,
Russell King <linux@....linux.org.uk>,
Zhangfei Gao <zhangfei.gao@...aro.org>,
Jun Nie <jun.nie@...aro.org>,
Ralf Baechle <ralf@...ux-mips.org>,
Govindraj Raja <govindraj.raja@...tec.com>,
Arnd Bergmann <arnd@...db.de>, heiko@...ech.de,
dianders@...omium.org, linux-samsung-soc@...r.kernel.org,
linux-mips@...ux-mips.org, linux-mmc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
CPGS <cpgs@...sung.com>
Subject: Re: [RFC PATCH v7 01/10] mmc: dw_mmc: Add external dma interface
support
On 2015/9/15 16:08, Jaehoon Chung wrote:
> Hi, Shawn.
>
[...]
>> -config MMC_DW_IDMAC
>> - bool "Internal DMAC interface"
>> - depends on MMC_DW
>> - help
>> - This selects support for the internal DMAC block within the Synopsys
>> - Designware Mobile Storage IP block. This disables the external DMA
>> - interface.
>> + PIO, internal DMA mode and external DMA mode.
>
> In future, i will add the quirk for broken IDMAC.
> This patch is absolutely depended on HCON register, but some IP can be broken it.
> how about?
>
That's fine to add broken IDMAC if some IP can support reading tranfer
mode from HCON.(I check IP 270a and 240a, they supports)
>>
>> config MMC_DW_PLTFM
>> tristate "Synopsys Designware MCI Support as platform device"
[...]
>> +static void dw_mci_edmac_stop_dma(struct dw_mci *host)
>> +{
>> + dmaengine_terminate_all(host->dms->ch);
>
> Does it need not to check "return value"?
>
Doesn't need. dmaengine_terminate_all return -ENOSYS if sub-dma drivers
doesn't implement terminate_all hook. Then nearly all the sub-dma
drivers always return 0(success) . That's why none of mmc host drivers
to check the return value here.
>> +}
>> +
>> +static int dw_mci_edmac_start_dma(struct dw_mci *host,
>> + unsigned int sg_len)
>> +{
>> + struct dma_slave_config cfg;
>> + struct dma_async_tx_descriptor *desc = NULL;
>> + struct scatterlist *sgl = host->data->sg;
>> + const u32 mszs[] = {1, 4, 8, 16, 32, 64, 128, 256};
>> + u32 sg_elems = host->data->sg_len;
>> + u32 fifoth_val;
>> + u32 fifo_offset = host->fifo_reg - host->regs;
>> + int ret = 0;
>> +
>> + /* Set external dma config: burst size, burst width */
>> + cfg.dst_addr = (dma_addr_t)(host->phy_regs + fifo_offset);
>> + cfg.src_addr = cfg.dst_addr;
>> + cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>> + cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>> +
>> + /* Match burst msize with external dma config */
>> + fifoth_val = mci_readl(host, FIFOTH);
>> + cfg.dst_maxburst = mszs[(fifoth_val >> 28) & 0x7];
>> + cfg.src_maxburst = cfg.dst_maxburst;
>
> The above configuration needs to set it at every time?
>
I think so. We call dw_mci_adjust_fifoth to make
configuraton more reasonable every time. So this setting correlates to
the fifoth calculated by dw_mci_adjust_fifoth.
>> +
>> + if (host->data->flags & MMC_DATA_WRITE)
>> + cfg.direction = DMA_MEM_TO_DEV;
>> + else /* MMC_DATA_READ */
>
> Can be removed the comment.
>
okay.
>> + cfg.direction = DMA_DEV_TO_MEM;
>> +
>> + ret = dmaengine_slave_config(host->dms->ch, &cfg);
[...]
>> + mmc->max_segs = 64;
>> + mmc->max_blk_size = 65536;
>> + mmc->max_blk_count = 65535;
>> + mmc->max_req_size =
>> + mmc->max_blk_size * mmc->max_blk_count;
>> + mmc->max_seg_size = mmc->max_req_size;
>
>
> WARNING: suspect code indent for conditional statements (8, 24)
> #349: FILE: drivers/mmc/host/dw_mmc.c:2599:
Sorry, but I can't find it?
./scripts/checkpatch.pl -f drivers/mmc/host/dw_mmc.c
total: 0 errors, 0 warnings, 3310 lines checked
drivers/mmc/host/dw_mmc.c has no obvious style problems and is ready for
submission.
> + } else if (host->use_dma == TRANS_MODE_EDMAC) {
> + mmc->max_segs = 64;
>
>
>> } else {
[...]
>> + */
>
> trans_mode can't take HCON value, but trans_mode reassigned to "TRANS_MODE_IDMAC" or "TRANS_MODE_EDMAC"..
> It's reassigned to host->use_dma...why can't use the host->use_dma?
>
> Your code..
>
> 1. trans_mode <- HCON value
> 2. Check trans_mode which interface use.
> then trans_mode <- TRANS_MODE_IDMAC/EDMAC/PIO
> 3. host->use_dma <- trans_mode
>
> isn't?
>
> It can be replaced to "host->use_dma" instead of "trans_mode".
>
yep, I intented to introduce a variable to make others clear the
mismatch meaning of databook. If you feel ok, I will remove trans_mode
in v8. :)
>> + trans_mode = SDMMC_GET_TRANS_MODE(mci_readl(host, HCON));
>> + if (trans_mode == DMA_INTERFACE_IDMA) {
[...]
>>
>> if (!host->dma_ops)
>> goto no_dma;
>
> This checking seems unnecessary, after applied your code.
>
Ahh... that's right, thanks for pointing it out.
> Best Regards,
> Jaehoon Chung
>
>> @@ -2562,12 +2733,12 @@ static void dw_mci_init_dma(struct dw_mci *host)
>> goto no_dma;
>> }
>>
>> - host->use_dma = 1;
>> + host->use_dma = trans_mode;
>> return;
>>
>> no_dma:
>> dev_info(host->dev, "Using PIO mode.\n");
>> - host->use_dma = 0;
>> + host->use_dma = trans_mode;
>> }
>>
>> static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset)
>> @@ -2650,10 +2821,9 @@ static bool dw_mci_reset(struct dw_mci *host)
>> }
>> }
>>
>> -#if IS_ENABLED(CONFIG_MMC_DW_IDMAC)
>> - /* It is also recommended that we reset and reprogram idmac */
>> - dw_mci_idmac_reset(host);
>> -#endif
>> + if (host->use_dma == TRANS_MODE_IDMAC)
>> + /* It is also recommended that we reset and reprogram idmac */
>> + dw_mci_idmac_reset(host);
>>
>> ret = true;
>>
>> @@ -3067,6 +3237,9 @@ EXPORT_SYMBOL(dw_mci_remove);
>> */
>> int dw_mci_suspend(struct dw_mci *host)
>> {
>> + if (host->use_dma && host->dma_ops->exit)
>> + host->dma_ops->exit(host);
>> +
>> return 0;
>> }
>> EXPORT_SYMBOL(dw_mci_suspend);
>> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
>> index 8ce4674..811d467 100644
>> --- a/drivers/mmc/host/dw_mmc.h
>> +++ b/drivers/mmc/host/dw_mmc.h
>> @@ -148,6 +148,12 @@
>> #define SDMMC_SET_FIFOTH(m, r, t) (((m) & 0x7) << 28 | \
>> ((r) & 0xFFF) << 16 | \
>> ((t) & 0xFFF))
>> +/* HCON register defines */
>> +#define DMA_INTERFACE_IDMA (0x0)
>> +#define DMA_INTERFACE_DWDMA (0x1)
>> +#define DMA_INTERFACE_GDMA (0x2)
>> +#define DMA_INTERFACE_NODMA (0x3)
>> +#define SDMMC_GET_TRANS_MODE(x) (((x)>>16) & 0x3)
>> /* Internal DMAC interrupt defines */
>> #define SDMMC_IDMAC_INT_AI BIT(9)
>> #define SDMMC_IDMAC_INT_NI BIT(8)
>> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
>> index 134c574..f67b2ec 100644
>> --- a/include/linux/mmc/dw_mmc.h
>> +++ b/include/linux/mmc/dw_mmc.h
>> @@ -16,6 +16,7 @@
>>
>> #include <linux/scatterlist.h>
>> #include <linux/mmc/core.h>
>> +#include <linux/dmaengine.h>
>>
>> #define MAX_MCI_SLOTS 2
>>
>> @@ -40,6 +41,17 @@ enum {
>>
>> struct mmc_data;
>>
>> +enum {
>> + TRANS_MODE_PIO = 0,
>> + TRANS_MODE_IDMAC,
>> + TRANS_MODE_EDMAC
>> +};
>> +
>> +struct dw_mci_dma_slave {
>> + struct dma_chan *ch;
>> + enum dma_transfer_direction direction;
>> +};
>> +
>> /**
>> * struct dw_mci - MMC controller state shared between all slots
>> * @lock: Spinlock protecting the queue and associated data.
>> @@ -154,7 +166,14 @@ struct dw_mci {
>> dma_addr_t sg_dma;
>> void *sg_cpu;
>> const struct dw_mci_dma_ops *dma_ops;
>> + /* For idmac */
>> unsigned int ring_size;
>> +
>> + /* For edmac */
>> + struct dw_mci_dma_slave *dms;
>> + /* Registers's physical base address */
>> + void *phy_regs;
>> +
>> u32 cmd_status;
>> u32 data_status;
>> u32 stop_cmdr;
>> @@ -208,8 +227,8 @@ struct dw_mci {
>> struct dw_mci_dma_ops {
>> /* DMA Ops */
>> int (*init)(struct dw_mci *host);
>> - void (*start)(struct dw_mci *host, unsigned int sg_len);
>> - void (*complete)(struct dw_mci *host);
>> + int (*start)(struct dw_mci *host, unsigned int sg_len);
>> + void (*complete)(void *host);
>> void (*stop)(struct dw_mci *host);
>> void (*cleanup)(struct dw_mci *host);
>> void (*exit)(struct dw_mci *host);
>>
>
>
>
>
--
Best Regards
Shawn Lin
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