Re: [Patch v6 2/2] dmaengine: Add ADM driver

From: Archit Taneja
Date: Thu May 21 2015 - 04:32:27 EST

Hi,

On 03/17/2015 11:16 AM, Andy Gross wrote:
Add the DMA engine driver for the QCOM Application Data Mover (ADM) DMA
controller found in the MSM8x60 and IPQ/APQ8064 platforms.

The ADM supports both memory to memory transactions and memory
to/from peripheral device transactions. The controller also provides flow
control capabilities for transactions to/from peripheral devices.

The initial release of this driver supports slave transfers to/from peripherals
and also incorporates CRCI (client rate control interface) flow control.

Signed-off-by: Andy Gross <agross@xxxxxxxxxxxxxx>
---
drivers/dma/Kconfig | 10 +
drivers/dma/Makefile | 1 +
drivers/dma/qcom_adm.c | 900 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 911 insertions(+)
create mode 100644 drivers/dma/qcom_adm.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index a874b6e..6919013 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -473,4 +473,14 @@ config QCOM_BAM_DMA
Enable support for the QCOM BAM DMA controller. This controller
provides DMA capabilities for a variety of on-chip devices.

+config QCOM_ADM
+ tristate "Qualcomm ADM support"
+ depends on ARCH_QCOM || (COMPILE_TEST && OF && ARM)
+ select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
+ ---help---
+ Enable support for the Qualcomm ADM DMA controller. This controller
+ provides DMA capabilities for both general purpose and on-chip
+ peripheral devices.
+
endif
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index f915f61..7f0fbe6 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -51,3 +51,4 @@ obj-$(CONFIG_INTEL_MIC_X100_DMA) += mic_x100_dma.o
obj-$(CONFIG_NBPFAXI_DMA) += nbpfaxi.o
obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
obj-$(CONFIG_IMG_MDC_DMA) += img-mdc-dma.o
+obj-$(CONFIG_QCOM_ADM) += qcom_adm.o
diff --git a/drivers/dma/qcom_adm.c b/drivers/dma/qcom_adm.c
new file mode 100644
index 0000000..7f8c119
--- /dev/null
+++ b/drivers/dma/qcom_adm.c
@@ -0,0 +1,900 @@
+/*
+ * Copyright (c) 2013-2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/dma-mapping.h>
+#include <linux/scatterlist.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_dma.h>
+#include <linux/reset.h>
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+
+#include "dmaengine.h"
+#include "virt-dma.h"
+
+/* ADM registers - calculated from channel number and security domain */
+#define ADM_CHAN_MULTI 0x4
+#define ADM_CI_MULTI 0x4
+#define ADM_CRCI_MULTI 0x4
+#define ADM_EE_MULTI 0x800
+#define ADM_CHAN_OFFS(chan) (ADM_CHAN_MULTI * chan)
+#define ADM_EE_OFFS(ee) (ADM_EE_MULTI * ee)
+#define ADM_CHAN_EE_OFFS(chan, ee) (ADM_CHAN_OFFS(chan) + ADM_EE_OFFS(ee))
+#define ADM_CHAN_OFFS(chan) (ADM_CHAN_MULTI * chan)
+#define ADM_CI_OFFS(ci) (ADM_CHAN_OFF(ci))
+#define ADM_CH_CMD_PTR(chan, ee) (ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_CH_RSLT(chan, ee) (0x40 + ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_CH_FLUSH_STATE0(chan, ee) (0x80 + ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_CH_STATUS_SD(chan, ee) (0x200 + ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_CH_CONF(chan) (0x240 + ADM_CHAN_OFFS(chan))
+#define ADM_CH_RSLT_CONF(chan, ee) (0x300 + ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_SEC_DOMAIN_IRQ_STATUS(ee) (0x380 + ADM_EE_OFFS(ee))
+#define ADM_CI_CONF(ci) (0x390 + ci * ADM_CI_MULTI)
+#define ADM_GP_CTL 0x3d8
+#define ADM_CRCI_CTL(crci, ee) (0x400 + crci * ADM_CRCI_MULTI + \
+ ADM_EE_OFFS(ee))
+
+/* channel status */
+#define ADM_CH_STATUS_VALID BIT(1)
+
+/* channel result */
+#define ADM_CH_RSLT_VALID BIT(31)
+#define ADM_CH_RSLT_ERR BIT(3)
+#define ADM_CH_RSLT_FLUSH BIT(2)
+#define ADM_CH_RSLT_TPD BIT(1)
+
+/* channel conf */
+#define ADM_CH_CONF_SHADOW_EN BIT(12)
+#define ADM_CH_CONF_MPU_DISABLE BIT(11)
+#define ADM_CH_CONF_PERM_MPU_CONF BIT(9)
+#define ADM_CH_CONF_FORCE_RSLT_EN BIT(7)
+#define ADM_CH_CONF_SEC_DOMAIN(ee) (((ee & 0x3) << 4) | ((ee & 0x4) << 11))
+
+/* channel result conf */
+#define ADM_CH_RSLT_CONF_FLUSH_EN BIT(1)
+#define ADM_CH_RSLT_CONF_IRQ_EN BIT(0)
+
+/* CRCI CTL */
+#define ADM_CRCI_CTL_MUX_SEL BIT(18)
+#define ADM_CRCI_CTL_RST BIT(17)
+
+/* CI configuration */
+#define ADM_CI_RANGE_END(x) (x << 24)
+#define ADM_CI_RANGE_START(x) (x << 16)
+#define ADM_CI_BURST_4_WORDS BIT(2)
+#define ADM_CI_BURST_8_WORDS BIT(3)
+
+/* GP CTL */
+#define ADM_GP_CTL_LP_EN BIT(12)
+#define ADM_GP_CTL_LP_CNT(x) (x << 8)
+
+/* Command pointer list entry */
+#define ADM_CPLE_LP BIT(31)
+#define ADM_CPLE_CMD_PTR_LIST BIT(29)
+
+/* Command list entry */
+#define ADM_CMD_LC BIT(31)
+#define ADM_CMD_DST_CRCI(n) (((n) & 0xf) << 7)
+#define ADM_CMD_SRC_CRCI(n) (((n) & 0xf) << 3)
+
+#define ADM_CMD_TYPE_SINGLE 0x0
+#define ADM_CMD_TYPE_BOX 0x3
+
+#define ADM_CRCI_MUX_SEL BIT(4)
+#define ADM_DESC_ALIGN 8
+#define ADM_MAX_XFER (SZ_64K-1)
+#define ADM_MAX_ROWS (SZ_64K-1)
+#define ADM_MAX_CHANNELS 16
+
+struct adm_desc_hw_box {
+ u32 cmd;
+ u32 src_addr;
+ u32 dst_addr;
+ u32 row_len;
+ u32 num_rows;
+ u32 row_offset;
+};
+
+struct adm_desc_hw_single {
+ u32 cmd;
+ u32 src_addr;
+ u32 dst_addr;
+ u32 len;
+};
+
+struct adm_async_desc {
+ struct virt_dma_desc vd;
+ struct adm_device *adev;
+
+ size_t length;
+ enum dma_transfer_direction dir;
+ dma_addr_t dma_addr;
+ size_t dma_len;
+
+ void *cpl;
+ dma_addr_t cp_addr;
+ u32 crci;
+ u32 mux;
+ u32 blk_size;
+};
+
+struct adm_chan {
+ struct virt_dma_chan vc;
+ struct adm_device *adev;
+
+ /* parsed from DT */
+ u32 id; /* channel id */
+
+ struct adm_async_desc *curr_txd;
+ struct dma_slave_config slave;
+ struct list_head node;
+
+ int error;
+ int initialized;
+};
+
+static inline struct adm_chan *to_adm_chan(struct dma_chan *common)
+{
+ return container_of(common, struct adm_chan, vc.chan);
+}
+
+struct adm_device {
+ void __iomem *regs;
+ struct device *dev;
+ struct dma_device common;
+ struct device_dma_parameters dma_parms;
+ struct adm_chan *channels;
+
+ u32 ee;
+
+ struct clk *core_clk;
+ struct clk *iface_clk;
+
+ struct reset_control *clk_reset;
+ struct reset_control *c0_reset;
+ struct reset_control *c1_reset;
+ struct reset_control *c2_reset;
+ int irq;
+};
+
+/**
+ * adm_free_chan - Frees dma resources associated with the specific channel
+ *
+ * Free all allocated descriptors associated with this channel
+ *
+ */
+static void adm_free_chan(struct dma_chan *chan)
+{
+ /* free all queued descriptors */
+ vchan_free_chan_resources(to_virt_chan(chan));
+}
+
+/**
+ * adm_get_blksize - Get block size from burst value
+ *
+ */
+static int adm_get_blksize(unsigned int burst)
+{
+ int ret;
+
+ switch (burst) {
+ case 16:
+ case 32:
+ case 64:
+ case 128:
+ ret = ffs(burst>>4) - 1;
+ break;
+ case 192:
+ ret = 4;
+ break;
+ case 256:
+ ret = 5;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+/**
+ * adm_process_fc_descriptors - Process descriptors for flow controlled xfers
+ *
+ * @achan: ADM channel
+ * @desc: Descriptor memory pointer
+ * @sg: Scatterlist entry
+ * @crci: CRCI value
+ * @burst: Burst size of transaction
+ * @direction: DMA transfer direction
+ */
+static void *adm_process_fc_descriptors(struct adm_chan *achan,
+ void *desc, struct scatterlist *sg, u32 crci, u32 burst,
+ enum dma_transfer_direction direction)
+{
+ struct adm_desc_hw_box *box_desc;
+ struct adm_desc_hw_single *single_desc;
+ u32 remainder = sg_dma_len(sg);
+ u32 rows, row_offset, crci_cmd;
+ u32 mem_addr = sg_dma_address(sg);
+ u32 *incr_addr = &mem_addr;
+ u32 *src, *dst;
+
+ if (direction == DMA_DEV_TO_MEM) {
+ crci_cmd = ADM_CMD_SRC_CRCI(crci);
+ row_offset = burst;
+ src = &achan->slave.src_addr;
+ dst = &mem_addr;
+ } else {
+ crci_cmd = ADM_CMD_DST_CRCI(crci);
+ row_offset = burst << 16;
+ src = &mem_addr;
+ dst = &achan->slave.dst_addr;
+ }
+
+ do {
+ box_desc = desc;
+ box_desc->cmd = ADM_CMD_TYPE_BOX | crci_cmd;
+ box_desc->row_offset = row_offset;
+ box_desc->src_addr = *src;
+ box_desc->dst_addr = *dst;
+
+ rows = remainder / burst;
+ rows = min_t(u32, rows, ADM_MAX_ROWS);
+ box_desc->num_rows = rows << 16 | rows;
+ box_desc->row_len = burst << 16 | burst;
+
+ *incr_addr += burst * rows;
+ remainder -= burst * rows;
+ desc += sizeof(*box_desc);
+ } while (remainder >= burst);

The piece of code doesn't work if sg length is less than burst size. The rows would come out as 0, incr_addr and remainder won't change. But the desc pointer would be still incremented.

The ADM hardware will see a corrupt box descriptor, followed by a single descriptor in the case of sg length < burst.

Other than this, patch looks good to me.

Thanks,
Archit

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